Critical size defects like after infection or cancer debridement are a major issue in bone surgery. In the non load-bearing case it would be desirable to have an alloplastic implant material which is highly biointegrated and even able to support bone formation. It is supposed to fil the gap only temporally so that the body is able to replace it by natural bone. Therefore, the implant material should be biocompatible, bioresorbable or at least biodegradable, it should bear an open macropore structure for a good vascularization and furthermore offer an easy handling during surgery. The idea of the presented work is to develop such a material on the base of a macroporous bioactive glass which is combined with a biodegradable elastic polymer.
In a first step nano- and macroporous bioglass scaffold are produced via a sponge template method. A PU sponge is soaked with a precursor solution containing amongst others a silica source, a calcium salt and Pluronic® F127 for the creation of nanopores. After coating and drying the initial sponge template is removed together with the Pluronic® F127 by calcination. For improved mechanical stability and elastic behaviour of the scaffolds these are coated with biodegradable polymers, like polyglycerol sebacate or a modified variant of the latter. The materials are characterized via scanning and transmission electron microscopy, X-ray diffraction, sorption experiments, infrared spectroscopy and compression tests.
The bioactive glass sponge replicas show nanopores of about 5 nm and a very good reproduction of the macroporous structure of the initial sponge with macropores in the range of several hundred micrometres, which is excellent for a good vascularization. Coating the bioactive glass replicas with the polymers leads to an elastic material which remains is macroporosity. The developed multifunctional scaffolds are promising candidates for an effective bone replacement material.
 Shih C., Lu P., Chen W., Chang, Y., Chien C., Ceram. Int. 40 (2014) 15019.