Bone-like material based on aerogels

Abstract

Humans in space suffer loss of bone mass that weakens their bone. This is due to bone remodeling processes in the spongious bone areas under the disuse conditions in near zero gravity. On the way to a better understanding of those processes interdisciplinary expertise inside DLR has been pulled together to develop and apply numerical and physical simulation methods. In this context the typical open porous sponge structure of polysaccharide aerogel coated with the bone mineral calcium phosphate, i.e., aerogel composite can be used as model system for structural and mechanical behaviour of cancellous bone, with a later option of using it as biocompatible bone surrogate or scaffold material. Bone-like material based on aerogels can be synthesized by mineralizing inorganic component, calcium phosphate in organic matrix of polysaccharides. Aerogels of polysaccharides, e.g., cellulose, chitosan, chitin and κ-carrageenan were used as organic matrix in this study because of their nanofelt fibrillar structure, chelating functional groups, biocompatibility and biodegradability1. The macroporous sponge structures (50 to 200 µm) were produced by emulsion template method. Electron microscopic images showed meso- and macroporous structures with a fibre thickness of about 10 to 20 nm. Simulated body fluid was used to mineralize calcium phosphate nanocrystal in macroporous structure. Supercritical CO2 was used to dry the polysaccharide-calcium phosphate composite structure. The properties of aerogel composite such as density, mechanical strength can be tuned by varying the concentration and composition of the organic and inorganic parts. The preliminary results would be presented and discussed.