Cytocompatibility of caffeic acid-silica hybrid materials

The hydroxycinnamoyl compound, caffeic acid (CA), broadly occurring in plants, is receiving special attention in materials science In this context, CA–based peptide biomaterials were recently developed as eco-friendly and multifunctional free radical scavengers useable in a wide range of consumer manufacture, ranging from cosmetics to household products, as well as clinical applications, including imaging, drug delivery and disinfection. Furthermore, a water-soluble chitosan-caffeic acid conjugate, effective in delaying lipid oxidation, was also synthetized. Herein, exploiting sol-gel route versatility, caffeic acid/silica materials were synthetized. Hybrids, chemically characterized mainly through spectroscopic techniques, varied in their relative caffeic acid content. The synthetized materials were able to elicit anti-radical properties. The CA amount appeared to be determinant in anti-radical activity, as well as in biocompatibility assessment. To this latter purpose, mouse embryonic fibroblast cell line NIH-3T3 cells, which are generally considered as a suitable cell model for studying material biocompatibility, were utilized and directly exposed to hybrid materials. Redox mitochondrial activity was evaluated by means of MTT test. Cell migration in hybrid treated samples was also investigated, highlighting that the increase in caffeic acid weight percentage entrapped in silica material was able to positively modulate cytocompatibility.