M. Lietzow K. Besecke, R. Hinterding, L. Burmeister, A. Hoffmann, A. Kampmann, M. Stiesch, N. Ehlert
Bone replacement for defects after infection or cancer debridement are a critical problem in bone surgery. Autografts are still the materials of choice but have the disadvantage of low availability. Therefore, the aim of the presented work is the development of an easy to use biodegradable implant material which supports the formation of new bone in the long term.
In a first step nano- and macroporous bioactive glass scaffolds are produced via a sponge template method. A medical PU sponge is soaked with a precursor solution containing TEOS, as a silica source, ethanol, water, hydrochloric acid, calcium nitrate and F127 as structure directing agent. After coating and drying the initial sponge is removed together with the SDA by calcination at 600 °C . For further improvement of the mechanical stability and to gain elastic be-haviour of the scaffolds these are coated with biodegradable polymers, like polytrimethylene carbonate and polyglyc-erol sebacate. The latter can be modified by a phosphate species in order to support bone formation. Current work is dedicated to incorporate more hydrophilic copolymers like poly ethylene glycol.
The materials are characterized via scanning and transmission electron microscopy, X-ray diffraction, sorption experi-ments, infrared spectroscopy and compression tests. Furthermore, biocompabitility is investigated via cytotoxicity tests.
The bioactive glass sponge replicas show nanopores of about 5 nm. The inner surface area was about 400 m2•g-1. The three-dimensonal open pore structure of the initial sponge template is well reproduced. The macropores show pore sizes in the range from 100 µm to about 600 µm. The polymer coating of the bioactive glass replicas lead to an improve-ment of the mechanical properties. The composites exhibit elastic mechanical behaviour. The developed multifunc-tional 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.