Study to elucidate effect of titanium dioxide nanoparticles on bacterial membrane potential and membrane permeability

Abstract

The interaction of metal oxide nanoparticles (NPs) with cells and lipid bilayers is precarious in various fields such as antibacterial and drug or gene delivery. These require a strong control over NPs–cell interactions, an understanding of how the NPs surface impact their interaction with lipid bilayers and cells. Therefore, to elucidate Titanium dioxide (TiO2) NPs of size 8–10 nm and 90–100 nm and their interaction with lipid bilayer of Escherichia coli and Staphylococcus aureus, we studied membrane potential, membrane permeability. Results of the traditional method of checking antibacterial activity - minimum inhibitory concentration (MIC) was co-related with change in membrane potential and membrane permeability. TiO2 NPs 8–10 nm have profound action on depolarization of membrane potential of E. coli cells, while of S. aureus were not affected. TiO2 NPs 90–100 nm have very less effect on membrane potential and permeability of both organisms. It is observed that there exists a strong co-relation between antibacterial activity of the TiO2 NPs and change in the membrane potential and membrane permeability. These observations are also supported by membrane leakage test by estimation of protein, deoxyribonucleic acid (DNA) and potassium ion (K+) ion content.