Preparation and antibacterial effects of Ag/AgCl-doped quaternary ammonium-modified silicate hybrid antibacterial material

Abstract

Organic-inorganic hybrid antibacterial materials based on Ag/AgCl and quaternary ammonium-modified silicate (Ormosil(NR₄⁺Cl^-)) were prepared by sol-gel processes and an in situ reduction method. The physical properties of Ormosil(NR₄⁺Cl^-) and the Ormosil(NR₄⁺Cl^-)/Ag hybrids were examined using FTIR, UV-Vis, SEM, XRD and NMR spectroscopy. The results indicated that Ag/AgCl was incorporated into the Ormosil(NR₄⁺Cl^-) matrix after impregnation. Morphological analysis by SEM showed uniformly-distributed Ag and AgCl particles in the Ormosil(NR₄⁺Cl^-) matrix, of spherical nature and a size around 5-20 and <200 nm. The antibacterial effects of Ormosil(NR₄⁺Cl^-) and the Ormosil(NR₄⁺Cl^-)/Ag hybrids against Gram-negative P. aeruginosa and E. coli, and Gram-positive S. aureus and B. subtilis, were assessed in terms of the zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and plate-counting method, and an excellent antibacterial performance was discovered. Moreover, the antibacterial performance of the Ormosil(NR₄⁺Cl^-)/Ag hybrid was better than that of Ormosil(NR₄⁺Cl^-) and the Ormosil/Ag hybrids.

Keywords: Antibacterial material; Nuclear magnetic resonance (NMR); Quaternary ammonium; Silver/silver chloride.