Design and synthesis of novel mesostructured nanohybrid materials as antimicrobials

Abstract

New transparent and monolithic silica hybrid gels with high antibacterial and antifungal activities have been synthesized by soft chemistry. The synthesis has been carried out via sol-gel process, by grafting difunctional-1,3,4-thiadiazole components into a silica network, using 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) as a silicon source. The obtained xerogels were characterized using 13C and 29Si CP MAS NMR, FTIR spectroscopy and SEM. The results of this study reveal that the 1,3,4-thiadiazole nuclei have been chemically cross-linked to the silica backbone structure leading to hybrid materials. The pore sizes and specific surface areas were evaluated using N2 adsorption/desorption isotherms. The specific surface area found to be ranged from 302 to 365 m2.g−1. Small particle size with a narrow pore size distribution and an average diameter between 2.5 and 3.5 nm characteristic of a mesoporous structure of xerogels was observed. Scanning electron microscopy showed that the xerogels were formed of spherical nanoparticles whose diameter is of around ten nanometers. Gels antimicrobial activity has been evaluated against Gram-negative and Gram-positive bacteria and the fungus Candida albicans. This study demonstrated significant biosafety of the as-synthesized products and cytocompatibility with normal human skin cells was observed, supporting their potential use as promising candidates for therapeutic application.