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  • 1.
    Abdollahi Sani, Negar
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mirbel, Deborah
    Univ Bordeaux, France.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Brochon, Cyril
    Univ Bordeaux, France.
    Cloutet, Eric
    Univ Bordeaux, France.
    Hadziioannou, Georges
    Univ Bordeaux, France.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    A ferroelectric polymer introduces addressability in electrophoretic display cells2019In: FLEXIBLE AND PRINTED ELECTRONICS, ISSN 2058-8585, Vol. 4, no 3, article id 035004Article in journal (Refereed)
    Abstract [en]

    During the last decades, tremendous efforts have been carried out to develop flexible electronics for a vast array of applications. Among all different applications investigated in this area, flexible displays have gained significant attention, being a vital part of large-area devices, portable systems and electronic labels etc electrophoretic (EP) ink displays have outstanding properties such as a superior optical switch contrast and low power consumption, besides being compatible with flexible electronics. However, the EP ink technology requires an active matrix-addressing scheme to enable exclusive addressing of individual pixels. EP ink pixels cannot be incorporated in low cost and easily manufactured passive matrix circuits due to the lack of threshold voltage and nonlinearity, necessities to provide addressability. Here, we suggest a simple method to introduce nonlinearity and threshold voltage in EP ink display cells in order to make them passively addressable. Our method exploits the nonlinearity of an organic ferroelectric capacitor that introduces passive addressability in display cells. The organic ferroelectric material poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) is here chosen because of its simple manufacturing protocol and good polarizability. We demonstrate that a nonlinear EP cell with bistable states can be produced by depositing a P(VDF-TrFE) film on the bottom electrode of the display cell. The P(VDF-TrFE) capacitor and the EP ink cell are separately characterized in order to match the surface charge at their respective interfaces and to achieve and optimize bistable operation of display pixels.

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  • 2.
    Abdullah, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Hafid, Abdelakram
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Shahid, H.
    Coventry University, Research Centre for Intelligent Healthcare, Coventry, United Kingdom.
    Comparing the Effectiveness of EMG and Electrical Impedance myography Measurements for Controlling Prosthetics2023In: IEEE Int. Multidiscip. Conf. Eng. Technol., IMCET, Institute of Electrical and Electronics Engineers Inc. , 2023, p. 189-193Conference paper (Refereed)
    Abstract [en]

    In recent years, the field of prosthetics has made significant progress towards creating prosthetic devices that are more functional, comfortable, and user-friendly. However, achieving intuitive control over prosthetic hand movements remains a significant challenge, especially for individuals with limb loss who rely on prosthetics for independent daily activities. To address this challenge, researchers have explored the potential of non-invasive techniques as electromyography (EMG) for prosthetic control. This paper aims to investigate the potential of using EMG and the electrical impedance myography (EIMG) techniques jointly for the measurement of hand movements. The study involved recording and comparing EMG and EIMG signals from a cohort of healthy individuals. These signals were captured during four distinct hand gestures: opening and closing the hand, as well as extending and flexing it, under varying time conditions, allowing for categorization into low and high-intensity movements. Data collection employed the Open BCI and ZRPI devices. The analysis of these signal waveforms revealed compelling results. Brachioradialis activity in EMG 2 exhibited an increase during open hand (0.015mV) and extension hand (0.009mV in low and 0.013mV in high intensity) gestures, accompanied by increased EIMG activity (56mV and 52mV respectively). Additionally, close hand (0.0018mV in low and 0.05mV in high intensity) and flexion hand (0.0075 in low intensity and 0.002 in high intensity) gestures exhibited heightened flexor carpi ulnaris activity with raised EIMG activity (57mV and 45mV respectively). These results proved to be consistent, acceptable, and aligned with existing literature. The findings of this paper indicate that both EMG and EIMG techniques could be used together to control custom-made hand prosthetics, demonstrating a significant development that could lead to more intuitive and easier-to-control prosthetics. Also, the results obtained could be valuable to researchers and engineers working in the prosthetics field, as it provides insights into the potential of non-invasive techniques for prosthetic control.

  • 3.
    Adawi, Rahim
    University of Skövde, School of Engineering Science.
    Preventing fatal effects of overworking: Product design solution2018Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    “Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn.

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    PREVENTING FATAL EFFECTS OF OVERWORKING – PRODUCT DESIGN SOLUTION / Rahim_Adawi
  • 4. Ajalloueian, Fatemeh
    et al.
    Zeiai, Said
    Rojas, Ramiro
    Department of Chemistry, Division of Polymer Chemistry, Uppsala University, Sweden.
    Fossum, Magdalena
    Hilborn, Jöns
    One-Stage Tissue Engineering of Bladder Wall Patches for an Easy-To-Use Approach at the Surgical Table2013In: Tissue Engineering. Part C, Methods, ISSN 1937-3384, E-ISSN 1937-3392, Vol. 19, no 9, p. 688-696Article in journal (Refereed)
    Abstract [en]

    We present a method for producing a cell-scaffold hybrid construct at the bedside. The construct is composed of plastic-compressed collagen together with a poly(e-caprolactone) (PCL)-knitted mesh that yields an integrated, natural-synthetic scaffold. This construct was evaluated by seeding of minced bladder mucosa, followed by proliferation in vitro. High mechanical strength in combination with a biological environment suitable for tissue growth was achieved through the creation of a hybrid construct that showed an increased tensile strength (17.9 +/- 2.6 MPa) when compared to plastic-compressed collagen (0.6 +/- 0.12 MPa). Intimate contact between the collagen and the PCL fabric was required to ensure integrity without delamination of the construct. This contact was achieved by surface alkaline hydrolysis of the PCL, followed by adsorption of poly(vinyl) alcohol. The improvement in hydrophilicity of the PCL-knitted mesh was confirmed through water contact angle measurements, and penetration of the collagen into the mesh was evaluated by scanning electron microscopy (SEM). Particles of minced bladder mucosa tissue were seeded onto this scaffold, and the proliferation was followed for 6 weeks in vitro. Results obtained from phase contrast microscopy, SEM, and histological staining indicated that cells migrated from the minced tissue particles and reorganized on the scaffold. Cells were viable and proliferative, with morphological features characteristic of urothelial cells. Proliferation reached the point at which a multilayer with a resemblance to stratified urothelium was achieved. This successful method could potentially be used for in vivo applications in reconstructive urology as an engineered autologous tissue transplant without the requirement for in vitro culture before transplantation.

  • 5.
    Ajaxon, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Can Bone Void Fillers Carry Load?: Behaviour of Calcium Phosphate Cements Under Different Loading Scenarios2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Calcium phosphate cements (CPCs) are used as bone void fillers and as complements to hardware in fracture fixation. The aim of this thesis was to investigate the possibilities and limitations of the CPCs’ mechanical properties, and find out if these ceramic bone cements can carry application-specific loads, alone or as part of a construct. Recently developed experimental brushite and apatite cements were found to have a significantly higher strength in compression, tension and flexion compared to the commercially available CPCs chronOS™ Inject and Norian® SRS®. By using a high-resolution measurement technique the elastic moduli of the CPCs were determined and found to be at least twice as high compared to earlier measurements, and closer to cortical bone than trabecular bone. Using the same method, Poisson's ratio for pure CPCs was determined for the first time. A non-destructive porosity measurement method for wet brushite cements was developed, and subsequently used to study the porosity increase during in vitro degradation. The compressive strength of the experimental brushite cement was still higher than that of trabecular bone after 25 weeks of degradation, showing that the cement can carry high loads over a time span sufficiently long for a fracture to heal. This thesis also presents the first ever fatigue results for acidic CPCs, and confirms the importance of testing the materials under cyclic loading as the cements may fail at stress levels much lower than the material’s quasi-static compressive strength. A decrease in fatigue life was found for brushite cements containing higher amounts of monetite. Increasing porosity and testing in a physiological buffer solution (PBS), rather than air, also decreased the fatigue life. However, the experimental brushite cement had a high probability of surviving loads found in the spine when tested in PBS, which has previously never been accomplished for acidic CPCs. In conclusion, available brushite cements may be able to carry the load alone in scenarios where the cortical shell is intact, the loading is mainly compressive, and the expected maximum stress is below 10 MPa. Under such circumstances this CPC may be the preferred choice over less biocompatible and non-degradable materials.

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  • 6.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Acciaioli, Alice
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Lionello, Giacomo
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia (UPC).
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Baleani, Massimilliano
    Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Elastic properties and strain-to-crack-initation of calcium phosphate bone cements: Revelations of a high-resolution measurement technique2017In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 74, p. 428-437Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) should ideally have mechanical properties similar to those of the bone tissue the material is used to replace or repair. Usually, the compressive strength of the CPCs is reported and, more rarely, the elastic modulus. Conversely, scarce or no data are available on Poisson's ratio and strain-to-crack-initiation. This is unfortunate, as data on the elastic response is key to, e.g., numerical model accuracy. In this study, the compressive behaviour of brushite, monetite and apatite cements was fully characterised. Measurement of the surface strains was done using a digital image correlation (DIC) technique, and compared to results obtained with the commonly used built-in displacement measurement of the materials testers. The collected data showed that the use of fixed compression platens, as opposed to spherically seated ones, may in some cases underestimate the compressive strength by up to 40%. Also, the built-in measurements may underestimate the elastic modulus by up to 62% as compared to DIC measurements. Using DIC, the brushite cement was found to be much stiffer (24.3 ± 2.3 GPa) than the apatite (13.5 ± 1.6 GPa) and monetite (7.1 ± 1.0 GPa) cements, and elastic moduli were inversely related to the porosity of the materials. Poisson's ratio was determined to be 0.26 ± 0.02 for brushite, 0.21 ± 0.02 for apatite and 0.20 ± 0.03 for monetite. All investigated CPCs showed low strain-to-crack-initiation (0.17–0.19%). In summary, the elastic modulus of CPCs is substantially higher than previously reported and it is concluded that an accurate procedure is a prerequisite in order to properly compare the mechanical properties of different CPC formulations. It is recommended to use spherically seated platens and measuring the strain at a relevant resolution and on the specimen surface.

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  • 7.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Acciaioli, Alice
    Lionello, Giacomo
    Ginebra, Maria-Pau
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Baleani, Massimiliano
    Compressive strength increase of calcium phosphate bone cements is accompanied by a stiffness increase2016Conference paper (Other academic)
  • 8.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fatigue performance of a high-strength, degradable calcium phosphate bone cement2018In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 79, p. 46-52Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) are clinically used as injectable materials to fill bone voids and to improve hardware fixation in fracture surgery. In vivo they are dynamically loaded; nonetheless little is known about their fatigue properties. The aim of this study was to, for the first time, investigate the fatigue performance of a high strength, degradable (brushitic) CPC, and also evaluate the effect of cement porosity (by varying the liquid to powder ratio, L/P) and the environment (air at room temperature or in a phosphate buffered saline solution, PBS, at 37 degrees C) on the fatigue life. At a maximum compressive stress level of 15 MPa, the cements prepared with an L/P-ratio of 0.22 and 0.28 ml/g, corresponding to porosities of approximately 12% and 20%, had a 100% probability of survival until run-out of 5 million cycles, in air. When the maximum stress level, or the L/P-ratio, was increased, the probability of survival decreased. Testing in PBS at 37 degrees C led to more rapid failure of the specimens. However, the high-strength cement had a 100% probability of survival up to approximately 2.5 million cycles at a maximum compressive stress level of 10 MPa in PBS, which is substantially higher than some in vivo stress levels, e.g., those found in the spine. At 5 MPa in PBS, all specimens survived to run-out. The results found herein are important if clinical use of the material is to increase, as characterisation of the fatigue performance of CPCs is largely lacking from the literature.

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  • 9.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Long-term degradation of brushite cements in three different liquids2016Conference paper (Other academic)
  • 10.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The influence of porosity on the fatigue properties of brushite cement2016In: Biomaterials for tissue engineering models, 2016Conference paper (Other academic)
  • 11.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Holmberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Compressive fatigue properties of a high-strength, degradable calcium phosphate bone cement – influence of porosity and environmentManuscript (preprint) (Other academic)
  • 12.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lionello, Giacomo
    bLaboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Ginebra, Maria-Pau
    cBiomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia .
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Baleani, Massimiliano
    bLaboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Italy.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Local stiffness measurements in apatite and brushite cements2015Conference paper (Other academic)
  • 13.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Dept. of Materials Science and Metallurgy, Technical University of Catalonia .
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    A non-drying porosity evaluation method for calcium phosphate cements2014In: 26th Symposium and Annual Meeting of the International Society for Ceramics in Medicine, 2014, p. 68-68Conference paper (Refereed)
  • 14.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Maazouz, Yassine
    Ginebra, Maria-Pau
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Evaluation of a porosity measurement method for wet calcium phosphate cements2015In: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 30, no 5, p. 526-536Article in journal (Refereed)
    Abstract [en]

    The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed to set in an aqueous environment and then immersed in isopropanol and stored under three different conditions: at room temperature, at room temperature under vacuum (300 mbar) or at 37􏰀C. The specimen mass was monitored regularly. Solvent exchange took much longer time to reach steady state in hydroxyapatite cements compared to brushite cements, 350 and 18 h, respectively. Furthermore, the immersion affected the quasi-static compressive strength of the hydroxyapatite cements. However, the strength and phase composition of the brushite cements were not affected by isopropanol immersion, suggesting that isopropanol solvent exchange can be used for brushite calcium phosphate cements. The main advantages with this method are that it is non-destructive, fast, easy and the porosity can be evaluated while the cements remain wet, allowing for further analysis on the same specimen. 

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  • 15.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mechanical Properties of Brushite Calcium Phosphate Cements2017In: The World Scientific Encyclopedia of Nanomedicine and Bioengineering II: Bioimplants, Regenerative Medicine, and Nano-Cancer Diagnosis and Phototherapy: Volume 3: Design of Bioactive Materials for Bone Repair and Regeneration / [ed] Shi, D., Singapore: World Scientific Pte Ltd. , 2017Chapter in book (Refereed)
  • 16.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Compressive Fatigue Properties of Acidic Calcium Phosphate Cement2014In: Proceedings of 7th World Congress of Biomechanics, 2014Conference paper (Refereed)
  • 17.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Long-term in vitro degradation of a high-strength brushite cement in water, PBS, and serum solution2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 575079Article in journal (Refereed)
    Abstract [en]

    Bone loss and fractures may call for the use of bone substituting materials, such as calcium phosphate cements (CPCs). CPCs can be degradable, and, to determine their limitations in terms of applications, their mechanical as well as chemical properties need to be evaluated over longer periods of time, under physiological conditions. However, there is lack of data on how the in vitro degradation affects high-strength brushite CPCs over longer periods of time, that is, longer than it takes for a bone fracture to heal. This study aimed at evaluating the long-term in vitro degradation properties of a high-strength brushite CPC in three different solutions: water, phosphate buffered saline, and a serum solution. Microcomputed tomography was used to evaluate the degradation nondestructively, complemented with gravimetric analysis. The compressive strength, chemical composition, and microstructure were also evaluated. Major changes from 10 weeks onwards were seen, in terms of formation of a porous outer layer of octacalcium phosphate on the specimens with a concomitant change in phase composition, increased porosity, decrease in object volume, and mechanical properties. This study illustrates the importance of long-term evaluation of similar cement compositions to be able to predict the material’s physical changes over a relevant time frame. 

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    Long-term in vitro degradation of a high-strength brushite cement in water, PBS, and serum solution
  • 18.
    Ajaxon, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Compressive fatigue properties of an acidic calcium phosphate cement—effect of phase composition2017In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, no 3, article id 41Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) are synthetic bone grafting materials that can be used in fracture stabilization and to fill bone voids after, e.g., bone tumour excision. Currently there are several calcium phosphate-based formulations available, but their use is partly limited by a lack of knowledge of their mechanical properties, in particular their resistance to mechanical loading over longer periods of time. Furthermore, depending on, e.g., setting conditions, the end product of acidic CPCs may be mainly brushite or monetite, which have been found to behave differently under quasi-static loading. The objectives of this study were to evaluate the compressive fatigue properties of acidic CPCs, as well as the effect of phase composition on these properties. Hence, brushite cements stored for different lengths of time and with different amounts of monetite were investigated under quasi-static and dynamic compression. Both storage and brushite-to-monetite phase transformation was found to have a pronounced effect both on quasi-static compressive strength and fatigue performance of the cements, whereby a substantial phase transformation gave rise to a lower mechanical resistance. The brushite cements investigated in this study had the potential to survive 5 million cycles at a maximum compressive stress of 13 MPa. Given the limited amount of published data on fatigue properties of CPCs, this study provides an important insight into the compressive fatigue behaviour of such materials. 

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  • 19.
    Alanko, Rosanna
    et al.
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Oskarsson, Tina
    Jönköping University, School of Health and Welfare, HHJ. Prosthetics and Orthotics.
    Kommunikation mellan patient och ortopedingenjör: En kvalitativ studie2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En studie har genomförts med syftet att undersöka diabetespatienters tolkning av informationen som ges av deras respektive ortopedingenjör under ett patientmöte samt undersöka vad ortopedingenjören anser sig ha förmedlat för information till patienten under patientmötet. Metoden i studien är kvalitativ där intervjuer med semistrukturerade öppna frågor har använts. I studien ingick två ortopedingenjörer samt två diabetespatienter. Efter avslutade intervjuer har materialet från intervjuerna analyserats och bildat kategorier. Dessa kategorier har sedan använts för att finna skillnader samt likheter mellan ortopedingenjörens och patientens tolkningar. Patientmötens har spelats in för att få möjligheten att se vart missförstånd uppstått. Genomgående i resultatet var att ortopedingenjören anser sig ha förmedlat mer information än vad patienten beskriver under intervjuerna. Några missförstånd upptäcktes men kommunikationen mellan parterna var god.  

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  • 20.
    Altmann, Brigitte
    et al.
    University of Freiburg, Germany.
    Karygianni, Lamprini
    University of Freiburg, Germany.
    Al-Ahmad, Ali
    University of Freiburg, Germany.
    Butz, Frank
    University of Freiburg, Germany.
    Bächle, Maria
    University of Freiburg, Germany.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Fürderer, Tobias
    Courtois, Nicolas
    Palmero, Paola
    Politecnico di Torino, Italy.
    Follo, Marie
    University of Freiburg, Germany.
    Chevalier, Jérôme
    Université de Lyon, France.
    Steinberg, Thorsten
    University of Freiburg, Germany.
    Kohal, Ralf Joachim
    University of Freiburg, Germany.
    Assessment of Novel Long-Lasting Ceria-Stabilized Zirconia-Based Ceramics with Different Surface Topographies as Implant Materials2017In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 27, no 40, article id 1702512Article in journal (Refereed)
    Abstract [en]

    The development of long-lasting zirconia-based ceramics for implants, which are not prone to hydrothermal aging, is not satisfactorily solved. Therefore, this study is conceived as an overall evaluation screening of novel ceria-stabilized zirconia-alumina-aluminate composite ceramics (ZA8Sr8-Ce11) with different surface topographies for use in clinical applications. Ceria-stabilized zirconia is chosen as the matrix for the composite material, due to its lower susceptibility to aging than yttria-stabilized zirconia (3Y-TZP). This assessment is carried out on three preclinical investigation levels, indicating an overall biocompatibility of ceria-stabilized zirconia-based ceramics, both in vitro and in vivo. Long-term attachment and mineralized extracellular matrix (ECM) deposition of primary osteoblasts are the most distinct on porous ZA8Sr8-Ce11p surfaces, while ECM attachment on 3Y-TZP and ZA8Sr8-Ce11 with compact surface texture is poor. In this regard, the animal study confirms the porous ZA8Sr8-Ce11p to be the most favorable material, showing the highest bone-to-implant contact values and implant stability post implantation in comparison with control groups. Moreover, the microbiological evaluation reveals no favoritism of biofilm formation on the porous ZA8Sr8-Ce11p when compared to a smooth control surface. Hence, together with the in vitro in vivo assessment analogy, the promising clinical potential of this novel ZA8Sr8-Ce11 as an implant material is demonstrated. 

  • 21.
    Anerillas, Luis Oliveros
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Kingham, Paul J.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lammi, Mikko
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Wiberg, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Kelk, Peyman
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Three-dimensional osteogenic differentiation of bone marrow mesenchymal stem cells promotes matrix metallopeptidase 13 (Mmp13) expression in type i collagen hydrogels2021In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 22, no 24, article id 13594Article in journal (Refereed)
    Abstract [en]

    Autologous bone transplantation is the principal method for reconstruction of large bone defects. This technique has limitations, such as donor site availability, amount of bone needed and morbidity. An alternative to this technique is tissue engineering with bone marrow-derived mesenchymal stem cells (BMSCs). In this study, our aim was to elucidate the benefits of culturing BMSCs in 3D compared with the traditional 2D culture. In an initial screening, we combined BMSCs with four different biogels: unmodified type I collagen (Col I), type I collagen methacrylate (ColMa), an alginate and cellulose-based bioink (CELLINK) and a gelatin-based bioink containing xanthan gum (GelXA-bone). Col I was the best for structural integrity and maintenance of cell morphology. Osteogenic, adipogenic, and chondrogenic differentiations of the BMSCs in 2D versus 3D type I collagen gels were investigated. While the traditional pellet culture for chondrogenesis was superior to our tested 3D culture, Col I hydrogels (i.e., 3D) favored adipogenic and osteogenic differentiation. Further focus of this study on osteogenesis were conducted by comparing 2D and 3D differentiated BMSCs with Osteoimage® (stains hydroxyapatite), von Kossa (stains anionic portion of phosphates, carbonates, and other salts) and Alizarin Red (stains Ca2+ deposits). Multivariate gene analysis with various covariates showed low variability among donors, successful osteogenic differentiation, and the identification of one gene (matrix metallopeptidase 13, MMP13) significantly differentially expressed in 2D vs. 3D cultures. MMP13 protein expression was confirmed with immunohistochemistry. In conclusion, this study shows evidence for the suitability of type I collagen gels for 3D osteogenic differentiation of BMSCs, which might improve the production of tissue-engineered constructs for treatment of bone defects.

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  • 22.
    Arbring Sjöström, Theresia
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Anton I.
    INSERM, INS, Inst Neurosci Syst, Aix Marseille University, Marseille, France.
    Bernard, Christophe
    INSERM, INS, Inst Neurosci Syst, Aix Marseille University, Marseille, France.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Poxson, David
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Design and Operation of Hybrid Microfluidic Iontronic Probes for Regulated Drug Delivery2021In: Advanced Materials Technologies, E-ISSN 2365-709X, Vol. 6, no 2, article id 2001006Article in journal (Refereed)
    Abstract [en]

    Highly controlled drug delivery devices play an increasingly important role in the development of new neuroengineering tools. Stringent - and sometimes contradicting - demands are placed on such devices, ranging from robustness in freestanding devices, to overall device miniaturization, while maintaining precise spatiotemporal control of delivery with high chemical specificity and high on/off ratio. Here, design principles of a hybrid microfluidic iontronic probe that uses flow for long-range pressure-driven transport in combination with an iontronic tip that provides electronically fine-tuned pressure-free delivery are explored. Employing a computational model, the effects of decoupling the drug reservoir by exchanging a large passive reservoir with a smaller microfluidic system are reported. The transition at the microfluidic-iontronic interface is found to require an expanded ion exchange membrane inlet in combination with a constant fluidic flow, to allow a broad range of device operation, including low source concentrations and high delivery currents. Complementary to these findings, the free-standing hybrid probe monitored in real time by an external sensor is demonstrated. From these computational and experimental results, key design principles for iontronic devices are outlined that seek to use the efficient transport enabled by microfluidics, and further, key observations of hybrid microfluidic iontronic probes are explained.

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  • 23.
    Atif, Abdul Raouf
    et al.
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Aramesh, Morteza
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Carter, Sarah-Sophia
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Tenje, Maria
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Mestres, Gemma
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Universal Biomaterial-on-Chip: a versatile platform for evaluating cellular responses on diverse biomaterial substrates2024In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 35, article id 2Article in journal (Refereed)
    Abstract [en]

    Microfluidics has emerged as a promising approach for assessing cellular behavior in vitro, providing more physiologically relevant cell culture environments with dynamic flow and shear stresses. This study introduces the Universal Biomaterial-on-Chip (UBoC) device, which enables the evaluation of cell response on diverse biomaterial substrates in a 3D-printed microfluidic device. The UBoC platform offers mechanical stimulation of the cells and monitoring of their response on diverse biomaterials, enabling qualitative and quantitative in vitro analysis both on- and off-chip. Cell adhesion and proliferation were assessed to evaluate the biocompatibility of materials with different physical properties, while mechanical stimulation was performed to investigate shear-dependent calcium signaling in pre-osteoblasts. Moreover, the applicability of the UBoC platform in creating more complex in vitro models by culturing multiple cell types was demonstrated, establishing a dynamic multicellular environment to investigate cellular interfaces and their significance in biological processes. Overall, the UBoC presents an adaptable tool for in vitro evaluation of cellular behavior, offering opportunities for studying various biomaterials and cell interactions in microfluidic environments.

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    FULLTEXT01
  • 24.
    Atif, Abdul Raouf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lacis, Ugis
    Department of Engineering Mechanics, KTH.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bagheri, Shervin
    Department of Engineering Mechanics, KTH.
    Mestres, Gemma
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Modelling adsorption of proteins and cells on biomimetic hydroxyapatite2021Conference paper (Other academic)
    Abstract [en]

    Calcium-deficient hydroxyapatite (CDHA), a biomaterial similar to the inorganic bone matrix, can be used in non-load bearing areas to promote bone regeneration. Upon implantation, CDHA is exposed to blood, leading to serum protein deposition on the surface and enabling cell attachment via membrane-bound receptors. In cell culture studies, biomaterials are often pre-incubated in serum supplemented medium to mimic this process. In this work, to study the extent the protein layer assists in cell adhesion, a Langmuir isotherm-based model for protein and cell adhesion kinetics was used. 

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    ESB 2021 Conference Poster
  • 25.
    Atif, Abdul Raouf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pujari-Palmer, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Evaluation of Ionic Interactions of Bone Cement-on-Chip2019Conference paper (Other academic)
    Abstract [en]

    INTRODUCTION: Biomaterials are synthetic materials that can be incorporated into the body to replace an impaired physiological function. Apatite calcium phosphate cements (CPCs), used for bone regeneration, give calcium-deficient hydroxyapatite (CDHA) as an end-product after a dissolution-precipitation reaction during fabrication. CDHA has a tendency to uptake calcium and release phosphate into cell culture medium. Potentially, this leads to depletion of calcium ions in solution, which can be detrimental to cell survival. The aim of this work is to embed CDHA in a microfluidic system and evaluate ion exchange at different flow rates.

    METHODS: CPC paste was cast into a 0.8mm pocket within a Polydimethylsiloxane (PDMS, cured at 60°C for 2h) mould. CPCs were set in 0.9% w/v NaCl at 37°C for 10 days resulting in CDHA. The PDMS containing the CDHA was then bonded to glass, leaving a 0.5mm channel gap. Minimum Essential Media (MEM, 1ml) was pumped through the channel at low (2µl/min), medium (8µl/min) and high (14µl/min) flow rates. A CDHA disc (ø=15mm, h=2mm) was immersed in MEM (1ml) at static conditions (0µl/min) for 24h. Stock Media was taken as control. Calcium and phosphorus concentrations were analysed using Inductively Coupled Plasma Optical Emission Spectroscopy.

    RESULTS & CONCLUSIONS: CDHA was successfully embedded in a microfluidic chip (Fig. 1A). Observed [Ca] and [P] levels were closer to levels in stock MEM at higher flow rates (Fig. 1B). We anticipate that osteoblast viability will improve when grown under flow, as opposed to static conditions, due to continuous replenishment of cell medium.

  • 26. Augustine, Robin
    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film2009In: Microwave and Optical Technology Letters, Vol. 51, no 5Article in journal (Refereed)
    Abstract [en]

    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film

  • 27. Augustine, Robin
    Biocompatibility study of beta tricalcium phosphate bioceramics and chitosan biopolymer and their use as phantoms for medical imaging applications2009In: Microwave and Optical Technology Letters, Vol. 51, no 12Article in journal (Refereed)
    Abstract [en]

    Beta tricalcium phosphate (b-TCP) bioceramics and chitosan biopolymers are used as biomedical implants because of their better biocompatibility and good bioresorption characteristics. As they are biomaterials, they have good interactions with microwave frequencies. b-TCP and chitosan powder, films, pellets, and gel are prepared and studied at the S-band microwave frequencies. Dielectric parameters such as dielectric constant, dielectric loss, conductivity, and S-parameters are evaluated. Dielectric parameters of different forms of b-TCP and chitosan show resemblance with that of human tissues. Hence, these materials can also be considered as potential phantoms for specific absorption rate measurements as well as in microwave imaging applications. V

  • 28. Augustine, Robin
    Biocompatibility study of hydroxyapatite-chitosan composite for medical applications at microwave frequencies2008In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 50, no 11, p. 2931-2934Article in journal (Refereed)
    Abstract [en]

    Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and chitosan (poly [(β-1-4) d-glucosamine]) biopolymer show good biocompatibility in vivo. They have biological origin and show excellent interactions with microwave. Microwave study of HAp made using different drying techniques and their composites with chitosan in the ISM band is presented. Pastes are made using HAp and chitosan with different ratios of mixing. The dielectric properties of this composites match with that of human fat, collagen tissues. Some of the compositions exhibit dielectric property close to that of natural bone. This makes them more biocompatible and better substitutes for natural bone. Thus composite bioceramics can be considered as phantom model constituents for imaging purposes.

  • 29.
    Aziz, Shazed
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez Gil, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Salahuddin, Bidita
    Univ Wollongong, Australia.
    Persson, Nils-Krister
    Univ Boras, Sweden.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Fast and High-Strain Electrochemically Driven Yarn Actuators in Twisted and Coiled Configurations2021In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 31, no 10, article id 2008959Article in journal (Refereed)
    Abstract [en]

    Commercially available yarns are promising precursor for artificial muscles for smart fabric-based textile wearables. Electrochemically driven conductive polymer (CP) coated yarns have already shown their potential to be used in smart fabrics. Unfortunately, the practical application of these yarns is still hindered due to their slow ion exchange properties and low strain. Here, a method is demonstrated to morph poly-3,4-ethylenedioxythiophene:poly-styrenesulfonate (PEDOT:PSS) coated multifilament textile yarns in highly twisted and coiled structures, providing >1% linear actuation in <1 s at a potential of +0.6 V. A potential window of +0.6 V and -1.2 V triggers the fully reversible actuation of a coiled yarn providing >1.62% strain. Compared to the untwisted, regular yarns, the twisted and coiled yarns produce >9x and >20x higher strain, respectively. The strain and speed are significantly higher than the maximum reported results from other electrochemically operated CP yarns. The yarns actuation is explained by reversible oxidation/reduction reactions occurring at CPs. However, the helical opening/closing of the twisted or coiled yarns due to the torsional yarn untwisting/retwisting assists the rapid and large linear actuation. These PEDOT:PSS coated yarn actuators are of great interest to drive smart textile exoskeletons.

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  • 30.
    Bacaksizlar, Ecenur
    Malmö University, Faculty of Culture and Society (KS), School of Arts and Communication (K3).
    U-Med: A Mobile Application and a Reverse Vending Machine for Individuals to Reduce Unused Medication Waste2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 31.
    Bang, Le Thi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Filho, Luimar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Synthesis and assessment of metallic ion migration through a novel calcium carbonate coating for biomedical implants2019In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981Article in journal (Refereed)
  • 32.
    Barba, Albert
    et al.
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Diez-Escudero, Anna
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Espanol, Montserrat
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Bonany, Mar
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Maria Sadowska, Joanna
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Guillem-Marti, Jordi
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Manzanares, Maria-Cristina
    Univ Barcelona, Dept Pathol & Expt Therapeut, Human Anat & Embryol Unit, Barcelona 08907, Spain.
    Franch, Jordi
    Univ Autonoma Barcelona, Sch Vet, Small Anim Surg Dept, Bone Healing Grp, E-08193 Barcelona, Spain.
    Ginebra, Maria-Pau
    Univ Politecn Cataluna, Dept Mat Sci & Met Engn, Biomat Biomech & Tissue Engn Grp, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Univ Politecn Cataluna, Barcelona Res Ctr Multiscale Sci & Engn, Ave Eduard Maristany 10-14, Barcelona 08019, Spain;Barcelona Inst Technol BIST, Inst Bioengn Catalonia IBEC, Barcelona 08028, Spain.
    Impact of Biomimicry in the Design of Osteoinductive Bone Substitutes: Nanoscale Matters2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 9, p. 8818-8830Article in journal (Refereed)
    Abstract [en]

    Bone apatite consists of carbonated calcium-deficient hydroxyapatite (CDHA) nanocrystals. Biomimetic routes allow fabricating synthetic bone grafts that mimic biological apatite. In this work, we explored the role of two distinctive features of biomimetic apatites, namely, nanocrystal morphology (plate vs needle-like crystals) and carbonate content, on the bone regeneration potential of CDHA scaffolds in an in vivo canine model. Both ectopic bone formation and scaffold degradation were drastically affected by the nanocrystal morphology after intramuscular implantation. Fine-CDHA foams with needle-like nanocrystals, comparable in size to bone mineral, showed a markedly higher osteoinductive potential and a superior degradation than chemically identical coarse-CDHA foams with larger plate-shaped crystals. These findings correlated well with the superior bone-healing capacity showed by the fine-CDHA scaffolds when implanted intraosseously. Moreover, carbonate doping of CDHA, which resulted in small plate-shaped nanocrystals, accelerated both the intrinsic osteoinduction and the bone healing capacity, and significantly increased the cell-mediated resorption. These results suggest that tuning the chemical composition and the nanostructural features may allow the material to enter the physiological bone remodeling cycle, promoting a tight synchronization between scaffold degradation and bone formation.

  • 33.
    Barba, Albert
    et al.
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Diez-Escudero, Anna
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Rappe, Katrin
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Espanol, Montserrat
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Montufar, Edgar B
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Bonany, Mar
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Sadowska, Joanna M
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Guillem-Marti, Jordi
    Barcelona Research Center in Multiscale Science and Engineering, Universitat Politecnica de Catalunya.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Manzanares, Maria-Cristina
    Human Anatomy and Embryology Unit, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona.
    Franch, Jordi
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Osteoinduction by Foamed and 3D-Printed Calcium Phosphate Scaffolds: Effect of Nanostructure and Pore Architecture2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 48, p. 41722-41736Article in journal (Refereed)
    Abstract [en]

    Some biomaterials are osteoinductive, that is, they are able to trigger the osteogenic process by inducing the differentiation of mesenchymal stem cells to the osteogenic lineage. Although the underlying mechanism is still unclear, microporosity and specific surface area (SSA) have been identified as critical factors in material-associated osteoinduction. However, only sintered ceramics, which have a limited range of porosities and SSA, have been analyzed so far. In this work, we were able to extend these ranges to the nanoscale, through the foaming and 3D-printing of biomimetic calcium phosphates, thereby obtaining scaffolds with controlled micro- and nanoporosity and with tailored macropore architectures. Calcium-deficient hydroxyapatite (CDHA) scaffolds were evaluated after 6 and 12 weeks in an ectopic-implantation canine model and compared with two sintered ceramics, biphasic calcium phosphate and β-tricalcium phosphate. Only foams with spherical, concave macropores and not 3Dprinted scaffolds with convex, prismatic macropores induced significant ectopic bone formation. Among them, biomimetic nanostructured CDHA produced the highest incidence of ectopic bone and accelerated bone formation when compared with conventional microstructured sintered calcium phosphates with the same macropore architecture. Moreover, they exhibited different bone formation patterns; in CDHA foams, the new ectopic bone progressively replaced the scaffold, whereas in sintered biphasic calcium phosphate scaffolds, bone was deposited on the surface of the material, progressively filling the pore space. In conclusion, this study demonstrates that the high reactivity of nanostructured biomimetic CDHA combined with a spherical, concave macroporosity allows the pushing of the osteoinduction potential beyond the limits of microstructured calcium phosphate ceramics.

  • 34.
    Barba, Albert
    et al.
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Diez-Escudero, Anna
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Rappe, Katrin
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autònoma de Barcelona.
    Espanol, Montserrat
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Montufar, Edgar
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fontecha, Pedro
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autònoma de Barcelona.
    Manzanares, Maria-Cristina
    Human Anatomy and Embryology Unit, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona.
    Franch, Jordi
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autònoma de Barcelona.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya.
    Osteogenesis by foamed and 3D-printed nanostructured calcium phosphate scaffolds: Effect of pore architecture2018In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 79, p. 135-147Article in journal (Refereed)
    Abstract [en]

    There is an urgent need of synthetic bone grafts with enhanced osteogenic capacity. This can be achieved by combining biomaterials with exogenous growth factors, which however can have numerous undesired side effects, but also by tuning the intrinsic biomaterial properties. In a previous study, we showed the synergistic effect of nanostructure and pore architecture of biomimetic calcium deficient hydroxyapatite (CDHA) scaffolds in enhancing osteoinduction, i.e. fostering the differentiation of mesenchymal stem cells to bone forming cells. This was demonstrated by assessing bone formation after implanting the scaffolds intramuscularly. The present study goes one step forward, since it analyzes the effect of the geometrical features of the same CDHA scaffolds, obtained either by 3D-printing or by foaming, on the osteogenic potential and resorption behaviour in a bony environment. After 6 and 12 weeks of intraosseous implantation, both bone formation and material degradation had been drastically affected by the macropore architecture of the scaffolds. Whereas nanostructured CDHA was shown to be highly osteoconductive both in the robocast and foamed scaffolds, a superior osteogenic capacity was observed in the foamed scaffolds, which was associated with their higher intrinsic osteoinductive potential. Moreover, they showed a significantly higher cell-mediated degradation than the robocast constructs, with a simultaneous and progressive replacement of the scaffold by new bone. In conclusion, these results demonstrate that the control of macropore architecture is a crucial parameter in the design of synthetic bone grafts, which allows fostering both material degradation and new bone formation. Statement of Significance 3D-printing technologies open new perspectives for the design of patient-specific bone grafts, since they allow customizing the external shape together with the internal architecture of implants. In this respect, it is important to design the appropriate pore geometry to maximize the bone healing capacity of these implants. The present study analyses the effect of pore architecture of nanostructured hydroxyapatite scaffolds, obtained either by 3D-printing or foaming, on the osteogenic potential and scaffold resorption in an in vivo model. While nanostructured hydroxyapatite showed excellent osteoconductive properties irrespective of pore geometry, we demonstrated that the spherical, concave macropores of foamed scaffolds significantly promoted both material resorption and bone regeneration compared to the 3D-printed scaffolds with orthogonal-patterned struts and therefore prismatic, convex macropores.

  • 35.
    Barba, Albert
    et al.
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Rappe, Katrin
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Fontecha, P
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Diez-Escudero, Anna
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Maazouz, Yassine
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Espanol, Montserrat
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Öhman Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Manzanares, Maria-Cristina
    Human Anatomy and Embryology Unit, Department of Pathology and Experimental Therapeutics, Universitat de Barcelona.
    Franch, Jordi
    Bone Healing Group, Small Animal Surgery Department, Veterinary School, Universitat Autonoma de Barcelona.
    Ginebra, Maria-Pau
    Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Universitat Politecnica de Catalunya.
    Nanostructured Calcium Phosphate Scaffolds Trigger Osteoinduction and Osteogenesis2017Conference paper (Refereed)
  • 36.
    Basu, Alex
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Celma, Gunta
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    In Vitro and in Vivo Evaluation of the Wound Healing Properties of Nanofibrillated Cellulose Hydrogels2018In: ACS Applied Bio Materials, E-ISSN 2576-6422, Vol. 1, no 6, p. 1853-1863Article in journal (Refereed)
    Abstract [en]

    Current trends in wound care research move toward the development of wound healing dressings designed to treat different types of wounds (e.g., burns and chronic wounds) and toward tailoring treatments for different stages of the wound healing process. In this context, the development of advanced nanotherapeutic materials is highlighted as a promising strategy to efficiently control specific phases of the wound healing process. Here, Ca2+-cross-linked wood-derived nanofibrillated cellulose (NFC) hydrogels are evaluated as wound healing dressings. In vitro biocompatibility assays were performed to study the interaction of the NFC hydrogels with cellular processes that are tightly related to wound healing. Moreover, an in vivo dermo-epidermic full thickness wound healing model in rat was used to uncover the wound healing ability of the Ca2+-cross-linked NFC hydrogels. The in vitro experiments showed that the NFC hydrogels were able to support fibroblast and keratinocyte proliferation. A potential effect of the hydrogels on triggering keratinocyte differentiation was furthermore proposed. In vivo, the NFC hydrogels stimulated healing without causing any adverse local tissue effects, potentially owing to their moisture-donating properties and the herein discussed aiding effect of the Ca2+-cross-linker on epidermal generation. Thus, this work extensively demonstrates the wound healing ability of NFC hydrogels and presents an important milestone in the research on NFC toward advanced wound healing applications.

  • 37.
    Basu, Alex
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Celma, Gunta
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ferraz, Natalia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Ion-crosslinked nanocellulose hydrogels promote wound healing in vitro and in vivo2019In: Scandinavian Society for Biomaterials Conference 2019 / [ed] Scandinavian Society for Biomaterials, 2019Conference paper (Refereed)
  • 38.
    Berg, Camilla
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Synthesis of Ion Substituted Ceramic Core-Shell Particles for Dental Applications2018Conference paper (Refereed)
    Abstract [en]

    Calcium phosphate spheres are interesting alternatives for dental applications due to their chemical similarity to teeth and biocompatibility. A spherical shape with a hollow cores allows for loading of therapeutic agents for drug delivery which potentially could be combined with other applications such as tooth remineralization and treatment of hypersensitivity.

    Precipitation reactions are one of the techniques used for synthesizing spherical particles, but little is known about the mechanism behind the sphere formation, which makes tuning of the material properties challenging. Previously, it has been shown that substituting ions can influence the crystallization process, which can enable greater control during the synthesis.In this study, several different substituting ions has been used in the synthesis of alkaline earth phosphates, to further investigate their role in sphere formation and to develop a robust synthesis technique.

    Particles of alkaline earth phosphates (Ca, Sr and Ba) were synthesized with a precipitation reaction. Solutions with constituent anions and cations were mixed at room temperature, and substituting ions (Mg, Ca or Sr) were added before heating at 60-100 °C. Reaction times varied between 10 minutes to 24 hours. Characterization of precipitates was performed with SEM, DLS and FIB to analyze morphology, size and cross-sections of the spheres. Crystal structure and atomic composition was analyzed with XRD and ICP-OES.

    Without substituting ions, precipitates had no specific shape and crystallized in an apatitic structure or as a hydrogenated phosphate. Substituting ions stabilized the initial amorphous phase during the reaction, hindering rapid crystal growth which allowed for self-assembly into hollow, spherical particles with a diameter between 300-700 nm. The phase composition and degree of ion substitution in the precipitates depended on the size and concentration of the substituting ions. The amount of substitution was determined in the range between 5-30 %, where precipitates with a low degree of substitution crystallized in a structure similar to β-tricalcium phosphate, whereas materials with a higher degree of substitution had an amorphous structure.

    In this study it was shown that it was possible to obtain hollow, spherical particles of calcium-, strontium- and barium phosphate, by using substituting ions during a precipitation reaction. This indicates that the approach can be used to tailor the properties of spherical particles intended for dental applications.

  • 39.
    Berglund, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Branting-Ekenbäck, C
    Ohlson, M
    En översikt över chairside CAD/CAM-system i Sverige. Garanteras patientsäkerheten genom CE-märkningen av utrustning och material?2013Report (Other academic)
    Abstract [sv]

    Inom odontologin har Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) blivit allt vanligare, främst på tandtekniska laboratorier, men tekniken blir också vanligare på tandläkarklinikerna, s.k. chairside CAD/CAM. Chairside CAD/CAM innebär att tandläkaren efter preparationen av en tand framställer tandersättningen i tre steg. I första steget används en intraoral scanner istället för den traditionella avtryckstagningen (Mörmann et al., 2002; Beuer et al., 2008; Hehn, 2001). Man kan även scanna modeller och avtryck, vilket kan vara bra om patienten har svårt att gapa eller har hög salivproduktion, då scannrarna är känsliga för fuktiga miljöer (Kachalia et al., 2010). Det digitala avtrycket överförs till datorn, där uppgifterna bearbetas och en modell av tänderna skapas i 3D. I det andra steget designar tandläkaren tandersättningen på 3D-modellen. Här bestämmer tandläkaren kusphöjd, kontakter approximalt, utsträckning mot preparationsgränsen och utseende på tandersättningen. I det tredje steget fräses tandersättningen fram ur ett keramblock i en fräsmaskin. Ofta målas kronan här för att karaktärisera den och ge den ett mer tandlikt utseende innan den bränns i ugn. Med större möjligheter att själv kunna sköta hela processen fram till färdig tandkonstruktion måste tandläkaren fundera över hur kvaliteten och säkerheten hos de färdiga produkterna kan säkerställas. Färdiga tandtekniska arbeten räknas som specialanpassade medicintekniska produkter och ska inte CE-märkas men de material som ingår i arbetet är oftast CE-märkta. Lag (1993:584) om medicintekniska produkter och Läkemedelsverkets föreskrifter (LVFS 2003:11) om medicintekniska produkter innehåller krav på att medicintekniska produkter som släpps ut på marknaden ska vara lämpliga och säkra för sina användningsområden genom att krav ställs som ska leda till att allvarliga avvikelser, olyckor och tillbud på grund av produkterna så långt som möjligt ska kunna undvikas. Avvikelser inkluderar här både funktionsfel och misstänkta biverkningar. Innan ett tandtekniskt laboratorium får börja leverera tandtekniska arbeten till tandläkare måste ett antal krav vara uppfyllda för att bl.a. säkerställa säkerheten hos dessa produkter för patienterna. Laboratoriet ska vara registrerat hos Läkemedelsverket och vid registreringen måste man intyga att man har en tillverkningsverksamhet som uppfyller de krav för specialanpassade medicintekniska produkter som ställs i LVFS 2003:11. Medicintekniska produkter ska konstrueras och tillverkas på ett sådant sätt att de inte äventyrar patienternas kliniska tillstånd eller säkerhet, användarnas eller i förekommande fall andra personers hälsa och säkerhet, när de används under avsedda förhållanden och för sitt avsedda ändamål. Riskerna med att använda produkterna ska vara acceptabla med tanke på fördelarna för patienten och förenliga med en hög hälso-och säkerhetsnivå. Detta innefattar omfattande krav både på produkt och tillverkningsprocess. Det finns en del oklarheter rörande hur det regelverk som styr framställningen av tandtekniska arbeten tillämpas för arbeten tillverkade med chairside CAD/CAM.

  • 40.
    Bicen Unluer, Ozlem
    et al.
    Eskisehir Tech Univ, Turkey.
    Emir Diltemiz, Sibel
    Eskisehir Tech Univ, Turkey.
    Say, Mehmet Girayhan
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Bionkit Co Ltd, Turkey.
    Hur, Deniz
    Eskisehir Tech Univ, Turkey.
    Say, Ridvan
    Bionkit Co Ltd, Turkey.
    Ersoz, Arzu
    Eskisehir Tech Univ, Turkey.
    A powerful combination in designing polymeric scaffolds: 3D bioprinting and cryogelation2022In: International Journal of Polymeric Materials, ISSN 0091-4037, E-ISSN 1563-535X, Vol. 71, no 4, p. 278-290Article in journal (Refereed)
    Abstract [en]

    Three-dimensional (3D) bioprinting technologies have great attention in different researching areas such as tissue engineering, medicine, etc. due to its maximum mimetic property of natural biomaterials by providing cell combination, growth factors, and other biomaterials. Bioprinting of tissues, organs, or drug delivery systems emerged layer-by-layer deposition of bioinks. 3D bioprinting technique has some complexity such as choice of bioink combination, cell type, growth, and differentiation. In this study, a composite material in 3D bioprinting studies has been developed for biofabrication of the cell carrying scaffolds namely cryogenic scaffolds. Cryogenic scaffolds are highly elastic and have a continuous interconnected macroporous structure in 3D biomaterials that enable the cell attachment, viability, and proliferation. Freeze-drying cryogelation process for the formation of cryogel scaffolds has been achieved firstly among 3D bioprinting studies. Cryogenic gelatin-hyaluronic acid (Gel-HA)-based 3D-bioprinted scaffolds have been fabricated and characterized by scanning electron microscope (SEM), optical microscope images, tensile tests, determination of swelling degree, and porosity. Then, L929 cells from mouse C3H/An have been attached to cryogenic Gel-HA scaffolds. Cell attachment, viability, and proliferation on cryogenic scaffolds have been investigated for 7 days. The results showed that a combination of 3D bioprinting technologies and cryogenic process provided a new direction on biomedical scaffolds.

  • 41.
    Biswas, Tuser
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Yu, Junchun
    University of Borås, Faculty of Textiles, Engineering and Business.
    Nierstrasz, Vincent
    University of Borås, Faculty of Textiles, Engineering and Business.
    Digital inkjet printing of antimicrobial lysozyme on pretreated polyester fabric2022Conference paper (Refereed)
    Abstract [en]

    Lysozyme was inkjet printed on two different polyester fabrics considering several challenges of printing enzymes on synthetic fabric surfaces. Wettability of both the fabrics were improved by alkaline pre-treatment resulting reduction in water contact angle to 60±2 from 95°±3 and to 80°±2 from 115°±2 for thinner and coarser fabric respectively. Activity of lysozyme in the prepared ink was 9240±34 units/ml and reduced to 5946±23 units/ml as of collected after jetting process (before printing on fabric). The formulated ink was effectively inkjet printed on alkali treated polyester fabric for antimicrobial applications. Retention of higher activity of the printed fabric requires further studies on enzyme-fibre binding mechanisms and understanding protein orientation on fabric surface after printing

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  • 42.
    Biswas, Tuser
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Yu, Junchun
    University of Borås, Faculty of Textiles, Engineering and Business.
    Nierstrasz, Vincent
    University of Borås, Faculty of Textiles, Engineering and Business.
    Enzyme immobilization on textiles by inkjet printing for advanced applications2019Conference paper (Refereed)
    Abstract [en]

    Immobilization of enzymes on textiles can impart a range of advanced applications e.g. anti-microbial, controlled release, drug delivery and bio-sensing (Wehrschütz-Sigl et al., 2010). Such applications enable minimal consumption, recovery, and reusability of these valuable bio-materials compared to their conventional textile applications in surface cleaning and finishing (Araujo et al., 2008). Methods used for immobilization can play important roles to ensure precise, flexible and contamination free application. Compared to many of the conventional methods of textile immobilization such as coating and screen-printing, digital inkjet technology offers many benefits for such advanced applications (Kan and Yuen, 2012). Among various inkjet technologies, drop-on-demand piezoelectric printing is a promising resource-efficient technology for enzyme immobilization. 

     

    The enzymes should retain high activity after the immobilization process. Various factors involved during inkjet printing (Saunders and Derby, 2014) and fabric characteristics (Mohamed et al., 2008) can influence this enzymatic activity. Factors concerning the inkjet procedure include rheology and ionic nature of ink along with the shear force and waveform generated inside a piezoelectric printhead (Magdassi, 2010). Factors dependent upon fabric characteristics include surface structure, pore size distribution, and binding mechanism (Nierstrasz and Warmoeskerken, 2003). In this work, we have studied the effects of inkjet procedures on enzymatic activity. Lysozyme being a stable and well-studied enzyme was chosen for our experiments. A Xennia Carnelian printer with a Dimatix QS10 industrial printhead was used for inkjetting. Lytic activity of lysozyme was studied by a UV-Vis spectrophotometer against decrease of Micrococcus lysodeikticus cell concentration at 450 nm. Results showed ca. 10-15% activity reduction of the jetted lysozyme ink. As all the ink and printer parameters were optimized, the probable reason for such reduction could be the effect of shear forces inside the printhead on three-dimensional conformation of lysozyme. In conclusion, our formulated lysozyme ink showed potential for printing textiles with probable activity reduction that require further investigation. 

  • 43.
    Biswas, Tuser
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Yu, Junchun
    University of Borås, Faculty of Textiles, Engineering and Business.
    Nierstrasz, Vincent
    University of Borås, Faculty of Textiles, Engineering and Business.
    Inkjet printing of enzymes on synthetic fabrics2022Conference paper (Refereed)
    Abstract [en]

    Enzymes can be immobilized on textiles to impart anti-microbial properties in a more environment-friendly manner compared to conventional biocide-based solutions. Such application requires ensuring precise, flexible and contamination-free immobilization methods that can be offered by digital printing compared to coating or screen-printing techniques. Drop-on-demand inkjet printing is a resource-efficient technology that can ensure these requirements. The use of polyester and polyamide-based fabrics is rising for applications ranging from apparel and home furnishing to hygiene and medical textiles. These fibers offer superior chemical, physical, and mechanical properties due to their inert nature but challenge the printing process due to hydrophobicity and lack of functional groups. Lysozyme and tyrosinase are two enzymes showing great potential for grafting on synthetic fabrics paving the way to use them for inkjet printing as well.

    Challenges for inkjet printing of enzymes on synthetic fabric surfaces come in multiple forms i.e. ink recipe formation, printer mechanics and fabric surface characteristics. The ink must maintain a suitable viscosity and surface tension for effective drop ejection and a feasible ionic nature for enzyme activity. Then, the enzyme must be able to sustain the temperature and shear stress generated inside an inkjet printhead. Finally, influential fabric characteristics include surface structure, pore size distribution, evaporation rate and binding mechanism. By considering these parameters, lysozyme and tyrosinase were successfully printed on variously modified synthetic fabrics using a combination of sustainable technologies.

  • 44.
    Blasi Romero, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Barbe, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Development and validation of a reusable microfluidic system for the evaluation of biomaterials’ biological properties2019Conference paper (Other academic)
  • 45.
    Broman, Adam
    et al.
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Rehabilitation.
    Blom, Gustav
    Jönköping University, School of Health and Welfare, HHJ, Dep. of Rehabilitation.
    Assessment of function of a 3D-printed body-powered upper limb prosthetic device2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Purpose

    Conventional arm-prosthesis are expensive to make and therefore limit the availability for users on the geographical locations there the user pays for it. This study compares the hand function of a 3D-printed prosthesis with lower production cost with a traditional prosthesis.

    Method

    A test person performed two different tests of hand function (Box and Block test and Nine-hole peg test) with a myoelectric trans radial prosthetic arm and a body powered 3D printed trans radial prosthetic arm. The test person also answered two parts of the orthotics and prosthetics users’ survey (OPUS) considering both prosthetic arms.

    Result

    The 3D-printed prosthesis performed worse than the traditional prosthesis in the two tests of hand function and generally worse in the questionnaire about the function of the prosthesis. Though it got higher values in comfort and affordability.

    Conclusion

    There was a significant difference in function between the 3D-printed prosthesis and the myoelectric prosthesis but the printed prosthesis could perform many activities in daily living. Whether the 3D-printed prosthetic device is priceworthy or not is hard to measure because of different criteria, therefore a conclusion is hard to reach.

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  • 46.
    Byström, Joseph Lazraq
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pujari-Palmer, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro2019In: Journal of Functional Biomaterials, E-ISSN 2079-4983, Vol. 10, no 4, article id 54Article in journal (Refereed)
    Abstract [en]

    Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of alpha TCP based PMCs. PMCs were significantly stronger than unmodified cement (38-49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.

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  • 47.
    Bäckman, Sandra
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Biomechanics and Biomedicine.
    Produktutvecklingsprojekt: En applikation till användandet av oxygenbehandling i hemmet.2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    According to statistics, in 2010 there were 26 individuals seen by a group of 100,000 who were depending in home oxygen therapy (HOT). Oxygen treatment adds a certain amount of Oxygen to the patient because the ability to breathe correctly and sufficiently is negatively affected.

    The dominant disease that leads to HOT is COPD, chronic obstructive pulmonary disease. As the name suggests, it is a chronic disease which gives inflammatory changes to the lung bronchioles. These changes affect the breathing surface which results in that the individuals’ respiratory capacity becomes reduced.

    The project used methods from dynamic product development with the user in focus. This to obtain a functional prototype that could be used by the target group and to fulfill the purpose, goals and requirements set for the project's results. An important component of the project therefore was to work with the collection of data. For this, various methods were used to obtain information from users as well as prescribers of HOT. All of the methods used have been tested earlier and proven reliable. This project collected information from interviews, observations, matrix arrays, risk analysis and usability testing in patients with HOT.

    The prototype developed in the project resulted in that the target group could perform live test without any risks during testing. The results showed that the aim and objective for the project were fulfilled, expressed in that patients would be able to move the oxygen tube used in HOT.

    It was further concluded that the results fulfilled the patients' desire and opportunity to move the Oxygen tube in their home and at the same time answered the questions that the project was to answer. There were no existing solutions to the problem which is included in the project, but it was possible to develop a first prototype that met the purpose and object of the project.

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    Examensarbete i Biomekanik
  • 48.
    Cai, Bing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Geopolymer-based drug formulations for oral delivery of opioids2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Opioid therapy for chronic pain generally use controlled release formulations to deliver analgesic drugs around-the-clock. Controlled release dosage forms can enlarge the therapeutic effect by controlling the rate and site of release. However, with high drug content, opioid formulations are easily targeted for non-medical use. With the increasing concern of opioid abuse, tamper-resistance becomes an important attribute for opioid controlled-release dosage forms. Geopolymers have been studied as drug carrier for opioids to improve the tamper-resistance but there are still some issues, such as curing condition and fast drug release in acid, have not been studied in detail yet. This thesis focuses on the optimization and evaluation of the geopolymer-based formulation on its controlled-release and tamper-resistance properties with the aim of achieving optimal therapeutic outcomes and reducing abuse potential.

    In this work, we showed some further improvement and evaluations on geopolymer-based drug formulations. The mechanical strength and porosity of geopolymers could be influenced by the curing conditions: high humidity for at least 48 hours could improve its mechanical strength, but elevated temperature only accelerated the geopolymerization but promoted water evaporation, leading to shrinkage and crack formation. Incorporating pH-sensitive organic polymers could improve the acid resistance of geopolymer formulation and thus reduce the risk of dose dumping. Comparing to a commercial opioid tablet, the geopolymer matrix have higher mechanical strength and could offer better resistance against physical manipulation and extraction under heating. The results provided solid experimental support on the potential for geopolymer as matrix for oral opioid delivery systems.

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  • 49.
    Cai, Bing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Evaluation of the resistance of a geopolymer-based drug delivery system to tampering2014In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 465, no 1-2, p. 169-174Article in journal (Refereed)
    Abstract [en]

    Tamper-resistance is an important property of controlled-release formulations of opioid drugs. Tamper-resistant formulations aim to increase the degree of effort required to override the controlled release of the drug molecules from extended-release formulations for the purpose of non-medical use. In this study, the resistance of a geopolymer-based formulation to tampering was evaluated by comparing it with a commercial controlled-release tablet using several methods commonly used by drug abusers. Because of its high compressive strength and resistance to heat, much more effort and time was required to extract the drug from the geopolymer-based formulation. Moreover, in the drug-release test, the geopolymer-based formulation maintained its controlled-release characteristics after milling, while the drug was released immediately from the milled commercial tablets, potentially resulting in dose dumping. Although the tampering methods used in this study does not cover all methods that abuser could access, the results obtained by the described methods showed that the geopolymer matrix increased the degree of effort required to override the controlled release of the drug, suggesting that the formulation has improved resistance to some common drug-abuse tampering methods. The geopolymer matrix has the potential to make the opioid product less accessible and attractive to non-medical users.

  • 50.
    Cai, Bing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bredenberg, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mellgren, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The effect of curing conditions on compression strength and porosity of metakaolin-based geopolymers2013In: Developments in Strategic Materials and Computational Design IV, John Wiley & Sons, 2013Conference paper (Refereed)
    Abstract [en]

    Geopolymers have been suggested to use as construction, waste treatment and fire proof materials and even drug delivery material due to its excellent mechanical strength, chemical stability and flame resistance. The aim of this study was to investigate the influence of temperature, time and humidity during curing on mechanical strength and porosity of geopolymers.

    The geopolymer precursor paste was obtained by mixing metakaolin, waterglass and de-ionized water. The paste was molded into cylindrical rubber moulds (6  12 mm) and cured under different conditions: i.e. temperatures (ambient temperature, 37°C and 90°C), humidity and time (24, 48 and 96 hours). The compressive strength was determined using a universal testing machine. Helium pycnometer was used to measure the porosity. Via x-ray diffraction the phase composition of the cured samples was determined.

    Elongated curing slightly decreased the total porosity of the tested geopolymers. Higher curing temperature increased the compressive strength after 24 hour but did not affect strength for longer curing times. In general, the samples cured in moisture had higher mechanical strength than those cured in air. But low compression strength of samples cured under high temperature and long time showed that some water content in geopolymer was essential to retaining its microstructure.

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