Antibacterial action of functional silicon dioxide: an investigation of the attachment and separation of bacteria

Abstract

Bactericidal proteins from the Moringa oleifera seed are reported to be suitable alternatives to conventional methods of bacterial reduction in water. In this study the cationic bactericidal M. oleifera proteins were isolated by attachment onto the surface of silicon dioxide. This functionalised SiO2(ƒ-SiO2) was then exposed to Escherichia coli and Micrococcus luteus to examine whether the ƒ-SiO2 could be used to inactivate the bacteria. The effect of the non-ionic surfactant dodecyl glucoside on the attachment of these bacteria to the ƒ-SiO2 was examined with the aim of developing a method of reusable bacterial inactivation. The primary result of this study was that the E. coli could be readily separated from the ƒ-SiO2, allowing the ƒ-SiO2 to be used for further bacterial inactivation. The regeneration of the ƒ-SiO2 was demonstrated using fluorescence microscopy on bacterial cells stained with propidium iodide, and zeta potential measurements. Future applications of this work include a reusable method of removing bacteria from contaminated water.