Biodegradable and bioactive hybrid organic–inorganic PEG-siloxane fibers. Preparation and Tcharacterization

A mixture of triethoxysilanefunctionalized poly(ethylene glycol), f-PEG, and tetraethoxysilane, TEOS, was used as precursors in the preparation of continuous hybrid f -PEG-siloxane sol–gel derived fibers. The fibers were spun by extrusion through a spinneret. The thus prepared fibers had a diameter of 20–50 m. 29Si-CPMAS NMR measurements confirmed that the functionalized PEG is incorporated into the siloxane network through covalent bonds. The hybrid fiber elasticity was much higher than that of fibers spun from sols with TEOS as the only source for silica. However, the f-PEG chain length plays a crucial role for the spinnability of the sol, since, as a result of bridging flocculation, macroscopic phase separation occurred readily with increasing chain length of the f-PEG. The fibers were shown to be effective substrates for the nucleation and growth of bonelike hydroxyapatite