Bone replacement after infection or cancer debridement are a critical problem in bone surgery. Therefore, the aim of the presented work is the development of a biodegradable implant material which can combat bacterial infection and support the formation of new bone at the same time.
In a first step nano- and macroporous bioglass scaffold are produced as a replica of porous PU sponge. The PU sponge is soaked with a precursor solution containing TEOS, as a silica source, ethanol, water, hydrochloric acid and F127 as structure directing agent. Additionally, it is possible to add a calcium or phosphate source. After coating and drying the initial sponge is removed together with the SDA by calcination at 600 °C . For improved mechanical stability of the scaffolds and possible drug carrier matrix for proteins these are coated with biodegradable polymers, namely chitosan or a mixture of chitosan and gelatine. In both cases the polymers are cross-linked by (3-glycydyloxypropyl)-trimethoxysilane. For a further functionalization nanoporous silica nanoparticles can be incorporated into the polymer matrix . These nanoporous nanoparticles can be applied as further drug delivery system, for example by loading with antibacterial metals like silver. The materials are characterized via scanning and transmission electron microscopy, X-ray diffraction, sorption experiments and infrared spectroscopy.
The sponge replicas show nanopores of about 6 nm and macropores in the range from micrometre to about 2 millime-tres. The surface area was determined to about 150 to 200 cm2 g-1.The polymer coatings lead to increased mechanical stability and were applied to deliver the bone growth factor BMP2 (bone morphogenetic protein 2). Furthermore, na-noporous silica nanoparticles (40-60 nm, surface area about 1100 m2 g-1) could be loaded with silver nanoparticles and incorporated into the polymer matrix. First in-vitro investigations of the unloaded base materials with human osteo-blasts showed a good general biocompatibility.
 Shih C., Lu P., Chen W., Chang, Y., Chien C., Ceram. Int. 40 (2014) 15019.
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