In Vitro and In Vivo (Rabbit, Guinea Pig, Mouse) Properties of a Novel Resorbable Polymer and Allogenic Bone Composite for Guided Bone Regeneration and Orthopedic Implants.

INTRODUCTION: Currently, there is no bone fixation material that could be fully replaced by the competent recipient bone. The creeping substitution of the bone graft by the recipient bone is the result of its unique potential related to the presence of bone morphogenetic proteins (BMPs). However, the size of the human bone limits the use of allogenic implants for surgical (orthopedic) fixation. The aim of this project was to develop a novel composite material for guided bone regeneration, consisting of human bone powder obtained from a tissue bank and a resorbable polymer (13 wt% of bone powder in a medical poly-l-lactide polymer). Such a biomaterial could possess osteoinductive properties and be used to manufacture bone fixation implants of different shapes and sizes.

MATERIALS AND METHODS: The samples were obtained by tape casting and foils pressing, and subsequently radiation sterilized with a dose of 35 kGy. Two cell lines-normal mouse embryo fibroblasts (Balb 3T3/c) and human fetal osteoblasts (hFOB 1.19)-were cultured with the extracts of the biomaterials (MTT assay) or in indirect contact with the evaluated biomaterials (agar diffusion method). In addition, cell viability was evaluated after 5 days of incubation with biomaterial using ThinCert tissue culture inserts. Then, the following in vivo examinations were conducted: acute systemic toxicity, skin irritation and sensitization, and local effects after implantation.

RESULTS: The evaluated composite material showed a high degree of cytocompatibility and biocompatibility according to the International Standards.

CONCLUSIONS: The preclinical evaluation we performed on the new, polylactide-based allogenic biomaterial opens up possibilities to patent pending and advanced in vivo testing.