Preparation, bioactivity, and cytotoxicity studies of poly(ester urethane)s/SiO₂ nanocomposites

Degradable poly(ester urethane)s (PEUS)/nanosilica composites are prepared, and a preliminary evaluation of their potential to be used in calcified tissue regeneration is performed. First, poly(ethylene glycol succinate) (PEGS) of different molecular weights is prepared and then a prepolymer with an excess of 1,6-hexamethylene diisocyanate is synthesized; this prepolymer is subsequently extended with 1,4-butanediol in the presence of nanosilica particles. The effects of the structures of PEGS and PEUS are studied by means of attenuated total reflectance infrared, gel permeation chromatography, X-ray diffraction, thermogravimetric analysis, optical microscopy, and scanning electron microscopy. The materials show that similar crystalline structure independently of the molecular weight, however, increases the thermal resistance with higher molecular weight of nanocomposites. After soaking in simulated body fluid, the appearance of apatite phosphate bands in Fourier transformed infrared spectra suggests the bioactive character of these composites. In addition, degradation and toxicity test are performed. The materials are degradable but not cytotoxic after 7 days of testing.