| 1. |
- Orru, Anna Maria, 1976, et al.
(författare)
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AHA! festival 2015
- 2015
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The AHA festival investigates the borders between art and science in a three-day event at the Chalmers University of Technology hosted by the Department of Architecture. An international festival intended to provide enlightening experiences, staging surprises, new thoughts and displaced perspectives that lead to alternative modes of thinking about the space between art and science. We invite scientists (physicists, historians, mathematicians, medical students), artists (dancers, musicians, painters, poets, chefs) and not least architects, who reside in these borderlands and wish to share their vision and work. The key intention is to celebrate both art and science as key knowledge building devices.
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| 2. |
- Jing, Yujia, 1985
(författare)
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Hyperthermia-responsive liposomal systems
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Sophisticated liposomal systems are emerging at an increasing rate to meet the demands for multifunctional drug carriers in chemotherapies in combined with hyperthermia. For example, liposomal drug carriers for temperature-controlled drug release under hyperthermic conditions have recently been tested in clinical trials. More advanced designs of liposomes are expected to release encapsulated contents and activate hidden surface-functions in response to heat stimulus. Towards this aim, the present thesis is focused on formulating asymmetric lipid systems that can preserve functional moieties, and reactivate the targeted function as well as release the encapsulated compounds upon local heating. The design of the asymmetric liposomal systems utilizes the heat-activated transmembrane lipid diffusion during gel to liquid-crystalline phase transitions of the lipid membranes.Rational design of advanced liposomal drug-delivery systems will require understanding of the physicochemical properties of lipid membranes under, e.g., hyperthermic conditions. Here, supported lipid membranes on planar solid surfaces were used for model studies of lipid composition yielding a gel to liquid crystalline phase-transition temperature in the range 40 – 45 °C. It was found that the liposome-to-membrane formation process is not only size-dependent but also governed by temperature. Two methods of preparing supported asymmetric lipid membranes were investigated. As a proof-of-concept, the upper leaflets were either replaced or chemically transformed by enzymatic hydrolysis. The processes were monitored using surface sensitive techniques such as quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI). The asymmetric structures were stable at a room temperature, while lipid flip-flop was induced upon increasing of the temperature. Transmembrane lipid exchange in the asymmetric structure under hyperthermic conditions was demonstrated by detecting, through streptavidin binding, biotinylated lipids appearing at the top leaflet which were first located in the lower leaflet. The protocols developed for the supported lipid systems were adapted for the preparation of asymmetric liposomes. Biotinylated asymmetric liposomes were used as a model system to demonstrate the principle of heat-activated targeting of asymmetric liposomes to streptavidin-coated surfaces. More biologically relevant interaction was utilized to replace the biotin-streptavidin function, where asymmetric cationic liposomes were binding to anionic supported membrane immobilized surfaces upon heating. The described strategies for assembly of asymmetric supported membranes provide a guide to the development of multifunctional drug carriers. The protocols used in experiments with supported membranes were readily adapted to the preparation of asymmetric liposomes. The ongoing study tests the asymmetric liposomes in vitro, which is designed to demonstrate hyperthermia treatment can enhance accumulation of liposomes in FaDu cells, and at the same time activate release of the encapsulated components. The results of in vitro tests can be used to analyze the feasibility of utilizing the asymmetric liposomes as a platform in vivo to explore further improvement in their functions upon microwave hyperthermia.
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| 3. |
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| 4. |
- Palmquist, Anders, 1977, et al.
(författare)
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Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants
- 2023
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 156, s. 125-145
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Forskningsöversikt (refereegranskat)abstract
- The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. Statement of significance: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient's age and disease status.
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| 5. |
- Bondesson, Johan, 1991, et al.
(författare)
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Definition of Tubular Anatomic Structures from Arbitrary Stereo Lithographic Surface
- 2017
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Ingår i: Initiative Seminar Engineering Health, 8-9 November 2017, Chalmers.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An accurate description of anatomies and dynamics of vessels is crucial to understand their characteristics and improve surgical techniques, thus it is the basis, in addition to surgeon experience, on which stent design and operation procedures rely. The process of producing this description is user intensive, and recent improvement in image processing of medical3D imaging allows for a more automated workflow. However, there is a need to bridge the gap from a processed geometry to a robust mathematical computational grid. By sequentially segmenting a tubular anatomic structure, here defined by a stereo lithographic (STL) surface, an initial centerline is formed by connecting centroids of orthogonal cross-sectional contours along the length of the structure. Relying on the initial centerline, a set of non-overlapping 2D cross sectional contours are defined along the centerline, a centerline which is updated after the 2D contours are produced. After a second iteration of producing 2D contours and updating the centerline, a full description of the structure is created. Our method for describing vessel geometry shows good coherence to existing method. The main advantages of our method include the possibility of having arbitrary triangulated STL surface input, automated centerline definition, safety against intersecting cross-sectional contours and automatic clean-up of local kinks and wrinkles.
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| 6. |
- Apelgren, Peter, et al.
(författare)
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Chondrocytes and stem cells in 3D-bioprinted structures create human cartilage in vivo.
- 2017
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage repair and replacement is a major challenge in plastic reconstructive surgery. The development of a process capable of creating a patient-specific cartilage framework would be a major breakthrough. Here, we described methods for creating human cartilage in vivo and quantitatively assessing the proliferative capacity and cartilage-formation ability in mono- and co-cultures of human chondrocytes and human mesenchymal stem cells in a three-dimensional (3D)-bioprinted hydrogel scaffold. The 3D-bioprinted constructs (5 × 5 × 1.2 mm) were produced using nanofibrillated cellulose and alginate in combination with human chondrocytes and human mesenchymal stem cells using a 3D-extrusion bioprinter. Immediately following bioprinting, the constructs were implanted subcutaneously on the back of 48 nude mice and explanted after 30 and 60 days, respectively, for morphological and immunohistochemical examination. During explantation, the constructs were easy to handle, and the majority had retained their macroscopic grid appearance. Constructs consisting of human nasal chondrocytes showed good proliferation ability, with 17.2% of the surface areas covered with proliferating chondrocytes after 60 days. In constructs comprising a mixture of chondrocytes and stem cells, an additional proliferative effect was observed involving chondrocyte production of glycosaminoglycans and type 2 collagen. This clinically highly relevant study revealed 3D bioprinting as a promising technology for the creation of human cartilage.
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| 7. |
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| 8. |
- Apelgren, Peter, et al.
(författare)
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In Vivo Human Cartilage Formation in Three-Dimensional Bioprinted Constructs with a Novel Bacterial Nanocellulose Bioink
- 2019
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Ingår i: Acs Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 5:5, s. 2482-2490
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 X 5 X 1 mm(3)) containing human nasal chondrocytes (10 M mL(-1)) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 +/- 13.8 cells per mm(2) observed after 30 days and 85.6 +/- 30.0 cells per mm(2) at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.
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| 9. |
- Baş, Yağmur, et al.
(författare)
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Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications
- 2023
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 24:12, s. 5605-5619
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.
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| 10. |
- Shah, Furqan A., et al.
(författare)
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Bioactive glass and glass-ceramic scaffolds for bone tissue engineering
- 2018
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Ingår i: Bioactive Glasses (Second Edition). - 9780081009369 ; , s. 201-33
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Bioactive glasses and glass-ceramics are a diverse group of materials possessing a unique set of physicochemical properties that make them useful for bone repair. Scaffolds for bone tissue engineering are subject to many requirements including biocompatibility, osteogenesis, biodegradability, and mechanical competence, all of which must be considered in the design features. This chapter addresses various scaffold fabrication techniques for melt-derived and sol-gel-derived compositions, polymer-based organic-inorganic composites, calcium phosphate-based inorganic-inorganic composites, bioactive bone cements, scaffolds based on glass compositions containing specific therapeutic ions, and hybrid materials where the organic and inorganic phases interact at the molecular level. The most important achievements, challenges and potential solutions, as well as the most promising areas of future research involving bioactive glasses and glass-ceramics for bone tissue engineering are presented.
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