New Scaffold Structure Based on Collagen. Fabrication and Biocompatibility Evaluation

Abstract

Development of bioactive material template for in vitro and in vivo synthesis of osteoinductive and biodegradable bone material was intensevely studied over the last decade and the research in the field of partial substitution of bone tissue, use a very large range of natural and synthetic polymers, inorganic components and their composites. Despite of composites collagen hydroxiapatite with a mimetic osseous composition until now was not defined a scaffold model suitable to biofunctionality of native osseous structure. The goal of the article is fabrication of a new scaffold structure, based on collagen fibrils with length 1–1.5 cm, thikness 0.1–0.3 and having a shroud structure. Collagen crosslinking was performed with aldehides in such way that aminic groups became bloked and carboxylic groups remain free in order to involve hydroxiapatite and biocompatible synthetic polymer (polyvinil alchol, polilactide) coupling. Crosslinking temperature for collagen fibrils is 70°C being a suitable temperature for resistance to “in vivo” resorbtion. Infrared spectra was performed and the amount of the hidroxyl bonds was correlated with hydrophilic [2] balance estimated from contact angle measurements. The morphology and the surface composition were determined with an Environmental Scanning Electron Microscope FEI/Phillips XL30 ESEM and all physical chemical properties especially surface features were used as basic factors in future cell growth and proliferation process. The main aim of biocompatibility tests is to multiply and to differentiate cells in vitro in osteoblasts from marrow. The environment of culture was supplemented with specific media containing Na β glicerofosfat and the cell was differentiated in osteoblasts. As arguments for differentiation were proposed the evidence of specific markers: osteonectine, sialoproteines and osteocalcine. Osteoprogenitors cells culture were tested on various samples of scaffold. Cell cultures were tested for alkaline phosphatase at a week after culture. The technique uses p-nitrophenole which is going to be change by alkaline phosphatase in dinitro-phenole.

Keywords:

• biocompatibility
• collagen
• new scaffold