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- Apelgren, Peter, et al.
(författare)
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Skin Grafting on 3D Bioprinted Cartilage Constructs In Vivo
- 2018
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Ingår i: Plastic and Reconstructive Surgery-Global Open. - : Ovid Technologies (Wolters Kluwer Health). - 2169-7574. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Three-dimensional (3D) bioprinting of cartilage is a promising new technique. To produce, for example, an auricle with good shape, the printed cartilage needs to be covered with skin that can grow on the surface of the construct. Our primary question was to analyze if an integrated 3D bioprinted cartilage structure is a tissue that can serve as a bed for a full-thickness skin graft. Methods: 3D bioprinted constructs (10x10x1.2mm) were printed using nanofibrillated cellulose/alginate bioink mixed with mesenchymal stem cells and adult chondrocytes and implanted subcutaneously in 21 nude mice. Results: After 45 days, a full-thickness skin allograft was transplanted onto the constructs and the grafted construct again enclosed subcutaneously. Group 1 was sacrificed on day 60, whereas group 2, instead, had their skin-bearing construct uncovered on day 60 and were sacrificed on day 75 and the explants were analyzed morphologically. The skin transplants integrated well with the 3D bioprinted constructs. A tight connection between the fibrous, vascularized capsule surrounding the 3D bioprinted constructs and the skin graft were observed. The skin grafts survived the uncovering and exposure to the environment. Conclusions: A 3D bioprinted cartilage that has been allowed to integrate in vivo is a sufficient base for a full-thickness skin graft. This finding accentuates the clinical potential of 3D bioprinting for reconstructive purposes.
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- Berglin, Mattias, 1970, et al.
(författare)
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The adhesion of the barnacle, Balanus improvisus, to poly(dimethylsiloxane) fouling-release coatings and poly(methyl methacrylate) panels: The effect of barnacle size on strength and failure mode
- 2001
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Ingår i: Journal of Adhesion Science and Technology. - 0169-4243. ; 15:12, s. 1485-1502
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Tidskriftsartikel (refereegranskat)abstract
- Measure men ts were made of the bond strength of cyprids and barnacles (Balanus improvisus) attached to poly(dimethylsiloxane) (PDMS) fouling-release coatings and poly(methyl methacrylate) (PMMA) panels as a function of barnacle base plate size (0.05-90 mm(2)). The vertical forces necessary to dislodge cyprids and newly metamorphosed barnacles (base plate < 0.5 mm(2)) were found to be equal for the two different substrates. This unexpected result was explained by the occurrence of cohesive failure in the cyprid/barnacle part. A significantly higher detachment force was observed for larger barnacles (base plate > 0.5 mm(2)) when dislodged from the PMMA compared to the PDMS. Analysis of the failure surfaces with light microscopy and scanning electron microscopy (SEM) showed a gradual transition in failure mode from a total cohesive within the barnacle to a mixed failure mode during barnacle growth. This transition. which is a measure of the balance between the cohesive strength of the barnacle base plate and the adhesion bond to the surface, occurs earlier or with smaller barnacles when detached from the PDMS. The quantification of the remaining fraction of the base plate at the polymeric failure surfaces appears to be a function of barnacle bioadhesive bond strength and is, therefore, suggested to be used as a new parameter for evaluating the release properties of new coatings formulations.
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- Dammström, S., et al.
(författare)
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On the interactions between cellulose and xylan, a biomimetic simulation of the hardwood cell wall
- 2009
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Ingår i: BioResources. - 1930-2126. ; 4:1, s. 3-14
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Tidskriftsartikel (refereegranskat)abstract
- The plant cell wall exhibits a hierarchical structure, in which the organization of the constituents on different levels strongly affects the mechanical properties and the performance of the material. In this work, the interactions between cellulose and xylan in a model system consisting of a bacterial cellulose/glucuronoxylan (extracted from aspen, Populus tremula) have been studied and compared to that of a delignified aspen fiber material. The properties of the materials were analyzed using Dynamical Mechanical Analysis (DMA) with moisture scans together with dynamic Infra Red -spectroscopy at dry and humid conditions. The results showed that strong interactions existed between the cellulose and the xylan in the aspen holocellulose. The same kinds of interactions were seen in a water-extracted bacterial cellulose/xylan composite, while unextracted material showed the presence of xylan not interacting with the cellulose. Based on these findings for the model system, it was suggested that there is in hardwood one fraction of xylan that is strongly associated with the cellulose, taking a similar role as glucomannan in softwood.
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- Felix, JM, et al.
(författare)
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Adhesion characteristics of oxygen plasma-treated rayon fibers
- 1994
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Ingår i: Journal of Adhesion Science and Technology. - 0169-4243 .- 1568-5616. ; 8, s. 163-180
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Tidskriftsartikel (refereegranskat)abstract
- The effect of oxygen plasma treatment of fiber on the adhesion between regenerated cellulose fiber and polyethylene (PE) was investigated using the single-fiber fragmentation test. In addition to allowing the calculation of the interfacial shear strength, the fragmentation test gave extensive information on shear transfer and failure mechanisms in the systems. It was found that oxygen plasma treatment enhanced the interfacial adhesion considerably, as established both by the calculated shear strength values and the birefringence patterns observed. The influence of treatment time on the adhesion was studied and fond to be a most important parameter. The role of surface chemistry and surface energetics of fiber in the interaction balance was investigated using electron spectroscopy for chemical analysis (ESCA) and contact angle measurements. It was seen that the changes in surface energetics owing to treatment had no positive effect on adhesion. Instead, the improved adhesion was ascribed to the presence of hydroperoxides, as detected by ESCA, on treated fibers. Decomposition of these peroxides is believed to occur at the production of single fiber specimens, and covalent bonds are formed between fiber and matrix.
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| 7. |
- Foldager, C. B., et al.
(författare)
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Aarhus Regenerative Orthopaedics Symposium (AROS): Regeneration in the ageing population
- 2016
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 87, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- The combination of modern interventional and preventive medicine has led to an epidemic of ageing. While this phenomenon is a positive consequence of an improved lifestyle and achievements in a society, the longer life expectancy is often accompanied by decline in quality of life due to musculoskeletal pain and disability. The Aarhus Regenerative Orthopaedics Symposium (AROS) 2015 was motivated by the need to address regenerative challenges in an ageing population by engaging clinicians, basic scientists, and engineers. In this position paper, we review our contemporary understanding of societal, patient-related, and basic science-related challenges in order to provide a reasoned roadmap for the future to deal with this compelling and urgent healthcare problem.
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- Gatenholm, P., et al.
(författare)
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Hygiene: Jellyfish are blueprint for new absorbent materials
- 2007
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Ingår i: Medical Textiles. - 0266-2078. ; :FEB., s. 9-
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Tidskriftsartikel (refereegranskat)abstract
- Four years ago, scientists from the Chalmers University of Technology and the Swedish Institute for Food and Biotechnology initiated a project aimed at examining the little-known mechanisms of jellyfish. The group found out that the jellyfish's structure is made of interacting proteins and polysaccharides that are built up in a highly hierarchic fashion. Ions were also found to play a key role in the mechanism.
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| 9. |
- Gellerstedt, F., et al.
(författare)
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Swelling behaviour of succinylated fibers
- 2000
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Ingår i: Cellulose. - 0969-0239 .- 1572-882X. ; 7:1, s. 67-86
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Tidskriftsartikel (refereegranskat)abstract
- The swelling behaviour of cellulosic fibers bearing various amounts of carboxylic groups introduced by succinylation was studied as a function of pH. Upon an increase of pH, the perimeter of the succinylated fibers expanded as measured with the Wilhelmy plate technique. The fibers pass two pH regimes of increased expansion, pH = 5 and pH = 9. These pH levels correlate with the conductometric titration, which reveals two inflection points in both the pH and conductivity values for the succinylated fibers. Determinations of fiber saturation points (FSP) confirm that the cell wall is largely affected by increased pH. Analysis of the fibers with ESEM (Environmental Scanning Electron Microscope) showed that bundles of fibrils were released from the surface of the succinylated fibers at higher pH. Wilhelmy measurements also showed that the surface roughness was more than doubled in fibers succinylated for 12 h as pH rose from 3.2 to 10. These results indicate that, as the charge of the fibers is increased, the swelling forces reach such levels of magnitude that they overcome the structural network forces holding the fiber wall together. The methodology applied can hence be used to quantify the fundamental gel properties of the fiber wall.
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| 10. |
- Goetz, Lee, et al.
(författare)
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A novel nanocomposite film prepared from crosslinked cellulosic whiskers
- 2009
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 75:1, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose whiskers are increasingly being used as a reinforcing phase in polymer systems and their use is a growing area of importance in bionanocomposite research. Although the reinforcing effect of cellulose whiskers has been studied in various polymers, the impact of crosslinking cellulose whiskers has not been explored so far. This work deals with the development of novel cellulose nanocomposites, wherein the cellulose nanowhiskers are crosslinked with poly(methyl vinyl ether-co-maleic acid) and poly(ethylene glycol). The morphology of the nanocomposite was studied using atomic force microscopy (AFM), which revealed a network structure embedded in a continuous phase. The water sorption studies demonstrated that the crosslinked nanocomposites are capable of absorbing up to ~ 900% water and have potential to be used as hydrogels.
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