| 1. |
- Helenius, Gisela, 1973, et al.
(författare)
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In vivo biocompatibility of bacterial cellulose
- 2006
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Ingår i: Journal of biomedical materials research. - : Wiley. - 1549-3296 .- 1552-4965. ; 76:2, s. 431-8
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Tidskriftsartikel (refereegranskat)abstract
- The biocompatibility of a scaffold for tissue engineered constructs is essential for the outcome. Bacterial cellulose (BC) consists of completely pure cellulose nanofibrils synthesized by Acetobacter xylinum. BC has high mechanical strength and can be shaped into three-dimensional structures. Cellulose-based materials induce negligible foreign body and inflammatory responses and are considered as biocompatible. The in vivo biocompatibility of BC has never been evaluated systematically. Thus, in the development of tissue engineered constructs with a BC scaffold, it is necessary to evaluate the in vivo biocompatibility. BC was implanted subcutaneously in rats for 1, 4, and 12 weeks. The implants were evaluated in aspects of chronic inflammation, foreign body responses, cell ingrowth, and angiogenesis, using histology, immunohistochemistry, and electron microscopy. There were no macroscopic signs of inflammation around the implants. There were no microscopic signs of inflammation either (i.e., a high number of small cells around the implants or the blood vessels). No fibrotic capsule or giant cells were present. Fibroblasts infiltrated BC, which was well integrated into the host tissue, and did not elicit any chronic inflammatory reactions. The biocompatibility of BC is good and the material has potential to be used as a scaffold in tissue engineering.
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| 2. |
- Omar, Omar, et al.
(författare)
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In vivo gene expression in response to anodically oxidized versus machined titanium implants.
- 2010
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Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 92:4, s. 1552-1566
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Tidskriftsartikel (refereegranskat)abstract
- A quantitative polymerase chain reaction technique (qPCR) in combination with scanning electron microscopy was applied for the evaluation of early gene expression response and cellular reactions close to titanium implants. Anodically oxidized and machined titanium miniscrews were inserted in rat tibiae. After 1, 3, and 6 days the implants were unscrewed and the surrounding bone was retrieved using trephines. Both the implants and bone were analyzed with qPCR. A greater amount of cells, as indicated with higher expression of 18S, was detected on the oxidized surface after 1 and 6 days. Significantly higher osteocalcin (at day 6), alkaline phosphatase (at days 3 and 6), and cathepsin K (at day 3) expression was demonstrated for the oxidized surface. Higher expression of tumor necrosis factor-alpha (at day 1) and interleukin-1beta (at days 1 and 6) was detected on the machined surfaces. SEM revealed a higher amount of mesenchymal-like cells on the oxidized surface. The results show that the rapid recruitment of mesenchymal cells, the rapid triggering of gene expression crucial for bone remodeling and the transient nature of inflammation, constitute biological mechanisms for osseointegration, and high implant stability associated with anodically oxidized implants. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009.
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