Collagen imobilization on poly (L-co-D, L lactic acid) scaffolds

Abstract

Bioreabsorbable polymers are widely used as scaffolds in tissue engineering. However, due to their hydrophobic nature, modification techniques based on graft of chemical functional groups and immobilization of bioactive molecules have been developed, in order to promote biofuncionalization of material surface, causing better interaction between cell / polymer. This study aim at developing and characterizing a biomimetic surface on scaffolds of the copolymer poly (L-co-D, L lactic acid) (PLDLA 70/30), by grafting of chemical functional groups and immobilized with collagen type I. The scaffolds will be obtained by porogen leaching, and submitted to photo-oxidation method of the material surface followed by grafting polymer polymerization of the acrylic acid solution (PLDLA-Acc) and immobilization of the type I collagen (PLDLA-Col). The surface sample will be characterized before and after surface modification treatment by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Attenuated Total Reectance Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and contact angle. Scaffolds cytocompatibilty will be evaluated by osteoblastic-like cell culture, submitted to cytotoxicity and initial cell adhesion assays, collagen synthesis and observation of cell morphology obtained by SEM. The biocompatibility of PLDLA-Col scaffolds will be evaluated by material implant into critical-size defect (8mm) carried out on calvarial Wistar rats. After 8 and 12 week of implant the area of new bone formed will be evaluated by histologically and histomorphometry assay. (AU)