A new biodegradable bone wax substitute with the potential to be used as a bone filling material

A novel biomaterial consisting of the biodegradable compounds hydroxyapatite, chitosan and starch was developed. Hydroxyapatite particles were modified in a layer-to-layer reaction with oxidised starch and deacetylated chitosan. In this manner, two kinds of particles with different surfaces were generated, one featuring deacetylated chitosan, the other one exhibiting oxidised starch at the outermost layer. Mixed together, these two kinds of particles form a homogeneous powder, which can be transformed into a paste by adding water. In contact with water the amino groups of deacetylated chitosan and the aldehyde groups of oxidised starch form a Schiff's base bonding the particles together. Particle size distribution of powder modified with polysaccharides was characterised by using a CILAS granulometer. Burn-out experiments carried out by TG-MS provided the organic/inorganic ratio. The morphology of the particles was analysed by SEM. The cytotoxicity of the new composite was examined in vitro by culturing MC3T3 mouse fibroblasts directly on the new material. The viability of MC3T3 cells was largely unaffected, and cells proliferated well on the surface of the new substance indicating excellent biocompatibility. In view of its mechanical stability, the new composite may also be used as a bone filling material in orthopedic surgery