SiO2/Sodium Alginate Hybrid Systems: Structural Features, Surface Properties and Antibacterial Assessment

In this work, SiO2 /sodium alginate (Si/Alg 2, 5, and 8 wt.%) hybrids are synthesized via the sol-gel route, with the aim of developing innovative materials for biomedical applications (e.g., as supports for cell growth and tissue regeneration). The synthesized hybrids are characterized in terms of structural, textural, and biological properties. Fourier-Transform Infrared spectroscopy (FTIR) confirms the successful formation of hybrid networks through hydrogen bonding interactions between Si and Alg chains. Brunauer–Emmett–Teller (BET) measurements reveal a decrease in the surface area with an increase in Alg content (from 325.2 m2 /g with 2 wt.% of Alg to 104.3 m2 /g with 8 wt.% of Alg), suggesting partial pore blocking or less homogeneous dispersion of the polymer within the silica matrix. Antibacterial assays on Enterococcus faecalis and Escherichia coli reveal that all the hybrids are biologically inert, as no inhibition halos were detected. Overall, these preliminary results underline that the incorporation of Alg into Si matrices enables the development of stable hybrid systems with a tailorable surface. Theoretical studies about the intermolecular interaction between polysaccharides and silica surfaces are ongoing.