Synthesis of in situ silica-alginate hybrid hydrogels by a sol-gel route

The preparation of silica-alginate hybrid hydrogels by a sol-gel route is proposed in this work. The in-situ synthesis of silica networks from tetraethoxysilane (TEOS) and aminopropyltriethoxysilane (APTES) precursors in an alginate matrix is assayed. The experimental parameters were analyzed in three consecutive stages to obtain hybrid materials with specific properties. Stage 1: effect of water and catalyst ratios. Stage 2: effect of the inorganic precursor¿s ratio. Stage 3: effect of concentration of the alginate solution. The hydrolysis-condensation reactions of the silica precursors were regulated by the alginate concentration, the silica precursor nature, and the HCl/inorganic/H2O ratio. Hybrids prepared with both silica precursors generate longer silica chains. High alginate amounts increase the storage modulus of synthesized hybrids, and high catalyst ratios reduce their stability. Compositions with alginate content of 5 and 8 (wt/v)%, TEOS/APTES weight ratio of 74/26, and without catalyst are suitable to evaluation for their application in tissue engineering