POSS/gelatin-polyglutamic acid hydrogel composites: Preparation, biological and mechanical characterization

Novel hydrogel composites based on natural gelatin matrix and containing different loading of a water soluble octa-ammonium POSS (POSS-NH ₃⁺), (from 0.5 to 2 wt%) have been prepared in this work and their biocompatibility and mechanical behavior have been tested. The presence of 1 wt% of POSS-NH₃⁺ molecules in the hydrogel matrix increased the amount of human plasma proteins adsorption and human keratinocyte adhesion at 24 hours. In addition, the presence of increasing amounts of POSS in the hydrogel matrix allowed to a significantly increase of the matrix swelling degree at acid and neutral pH. Finally, a significant modulation of the mechanical characteristics (Young modulus, strain at break) of the hydrogel matrix induced by the presence of different amounts of POSS-NH₃⁺ was observed. The novel ability of POSS-NH ₃⁺ to modulate both biological and mechanical properties of a natural hydrogel could be useful for the production of new composites of interest for soft tissue engineering.