Cross-linked fumarate copolymer/chitosan scaffold for bone tissue engineering

M. LAURA LASTRA; M. SILVINA MOLINUEVO; M. SUSANA CORTIZO; ANA M. CORTIZO

Vina del Mar

Taller; 3 er Taller de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos; 2013

Sociedad Latinoamericana de Organos Artificiales, biomateriales e Ingenieria de tejidos

Bone tissue engineering is an emerging approach to provide viable substitutes for bone regeneration. Chitosan is a good candidate of bone scaffold which was widely used because of several advantages such as hydrophilicity, biocompatibility and noncitotoxicity. However, its low compressive strength limits application for bone regeneration. We have previously studied fumarate derived polymers (diisopropyl fumarate) for bone tissue engineering. The fumarate homopolymer alone presents low biocompatibility and it is too brittle to be used for bone regeneration applications. In an attempt to improve their mechanical and biological properties we have prepared polyesters-fumarate-based blends, which showed better biocompatibility results. In this work diisopropyl fumarate-vinyl acetate copolymer, a hydrophobic nonionic polymer was synthesized in order to obtain a new material for scaffold preparation. The copolymer was partially hydrolyzed with the purpose of generating OH groups on the macromolecular structure improving compatibility with chitosan. Then a blend between chitosan and fumarate copolymer was crosslinked by borax. SEM studies of the scaffolds revealed a rough surface with a laminar arrangement without phase separation. Bone marrow progenitor cells were used for biocompatibility and cytotoxicity assays. Bone marrow progenitor cells were isolated from bone marrow aspirates of rat femora and cultivated on the membranes surfaces during 7 days (proliferation assay) or 15 days (osteogenic differentiation assays). Bone marrow progenitor cells adhered and proliferated well along the time of culture. Cell morphology was conserved with cells showing the characteristic fibroblastic shape of bone marrow progenitor cells. Osteoblastic differentiation was performed incubating the cells in an osteogenic media containing -glicerolphosphate and ascorbic acid. After 15 days osteogenic studies showed that these cell types expressed osteoblastic markers such as alkaline phosphatase, collagen type I and mineral nodules. Altogether our results suggest that our chitosan / fumarate crosslinked polymer would be useful in bone tissue regeneration.