New biocides based on imidazolinium-functionalised hybrid mesoporous silica nanoparticles

Abstract

Here, we report the development of a new biocide based on hybrid mesoporous silica nanoparticles (MSN). The MSN was synthesized by condensation method in emulsion followed by grafting with two different silylated ionic liquid moieties, namely butyl imidazolinium bromide and imidazolinium propansulfonate betaine. Features of nanoparticles were characterized by Thermogravimetry, Infrared and ss-NMR Spectroscopy, and Transmission Electron Microscopy. The antibacterial properties were tested against a Gram-positive bacterial strain previously isolated from artefacts of interest in the field of Cultural Heritage. Interestingly, the hybrid material presents an antibacterial activity higher than its single constituents, showing a synergic effect probably due to the high local concentration of the ionic liquid anchored to nanoparticles. The more promising material was applied to fragments of stones retrieved from the Santa Margherita cave (Italy) and affected by bio-deterioration, comparing its antibacterial action with a commercial biocide.