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- Forsgren, Johan, et al.
(författare)
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In Vivo Evaluation of Functionalized Biomimetic Hydroxyapatite for Local Delivery of Active Agents
- 2011
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Ingår i: Journal of Biomaterials and Nanobiotechnology. - : Scientific Research Publishing, Inc.. - 2158-7027 .- 2158-7043. ; 2:2, s. 149-154
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Tidskriftsartikel (refereegranskat)abstract
- This study was carried out to investigate the biological response in vivo to biomimetic hydroxyapatite implant coatings functionalized with bisphosphonates and bone morphogenetic proteins. The functionalization was carried out by a simple soaking procedure in the operating room immediately prior to surgery. Cylindrical titanium samples with and without coatings were implanted in the distal femoral epiphysis of sheep and retrieved after 6 weeks. The histological analysis proved that all samples were integrated well in the tissue with no signs of intolerance. Fewer osteoclasts were observed in the vicinity of bisphosphonate-functionalized samples and the bone was denser around these samples compared to the other samples. Samples functionalized with bone morphogenetic protein induced more bone/implant contact but showed a more inconsistent outcome with reduced bone density around the samples. This study demonstrates a simple method to functionalize implant coatings, which provides surgeons with an option of patient-specific functionalization of implants. The observed biological impact due to the delivery of active molecules from the coatings suggests that this strategy may also be employed to deliver antibiotics from similar coatings.
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- Hulsart-Billström, Gry, et al.
(författare)
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Morphological differences in BMP-2-induced ectopic bone between solid and crushed hyaluronan hydrogel templates
- 2013
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 24:5, s. 1201-1209
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to affect bone formation by using crushed versus solid hydrogels as carriers for bone morphogenetic protein 2 (BMP-2) was studied. Hydrogels, based on chemical crosslinking between hyaluronic acid and poly(vinyl alcohol) derivatives, were loaded with BMP-2 and hydroxyapatite. Crushed and solid forms of the gels were analyzed both in vitro via a release study using I-125 radioactive labeling of BMP-2, and in vivo in a subcutaneous ectopic bone model in rats. Dramatically different morphologies were observed for the ectopic bone formed in vivo in the two types of gels, even though virtually identical release profiles were observed in vitro. Solid hydrogels induced formation of a dense bone shell around non-degraded hydrogel, while crushed hydrogels demonstrated a uniform bone formation throughout the entire sample. These results suggest that by crushing the hydrogel, the construct's three-dimensional network becomes disrupted. This could expose unreacted functional groups, making the fragment's surfaces reactive and enable limited chemical fusion between the crushed hydrogel fragments, leading to similar in vitro release profiles. However, in vivo these interactions could be broken by enzymatic activity, creating a macroporous structure that allows easier cell infiltration, thus, facilitating bone formation.
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