Design of an in situ-castable bioceramic bone tissue scaffold

Abstract

Bone defects are treated with bone grafts, replacing damaged or diseased bone tissue with either natural bone or bone substitutes. Synthetic graft materials, particularly bioactive glasses, have been developed to overcome the immunological and structural limitations of natural bone grafts. However, the success of bioactive glasses is limited by current approaches to fabrication of bioceramic scaffolds, of which no technique meets the design criteria for an ideal synthetic bone tissue scaffold; namely, formability, geometric stability, porosity, load-bearing capacity, bioactivity, and resorbability. To fulfil these design criteria, this work proposes a new approach to bioactive glass ceramic scaffold fabrication, producing an all-ceramic porous scaffold that can be cast in situ to repair bone defects. This ambient temperature and pressure process utilises a reaction with a liquid ceramic precursor to form a silicate-glass binder phase which consolidates bioactive glass frit. The resultant composite paste can be applied conformally to unique wound geometries before reacting with carbon dioxide gas to set into a rigid, load-bearing scaffold with an interconnected network of open pores. The effect of composition on the fulfilment of the design criteria was investigated via characterisation of the composite morphology, mechanical properties, and in vitro immersion response in simulated body fluid. It was shown that the composite scaffolds designed, produced, and analysed in this research fulfilled all established design criteria, signifying their potential success as bone tissue scaffolds.