Adhesion behavior of silica nanoparticles with bacteria: Spectroscopy measurements based on kinetics, and molecular docking

Nanoparticles are intriguing researchers due to their unique properties. In this study, the Stöber method was used to obtain white particles. Through scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis, the spherical nano-scale particles were confirmed to be nano-silica. Bacteria adsorption experiment displayed that nano-silica could be accumulated on the surface of bacteria. The ultraviolet and fluorescence spectroscopy were used to explain the interaction between silica nanoparticles and recombinant protein A (S. aureus membrane protein) under simulated physiological conditions. The results of UV–vis and fluorescence experiments showed that the quenching mechanism between silica nanoparticles and recombinant protein A was static quenching. The key enzymes in bacterial cell wall synthesis (β-lactamase) and fatty acid biosynthesis (FabI and FabH) pathways were selected, and the molecular docking results explained that silica nanoparticles adhered to the surface of E. coli and S. aureus through forming hydrogen bond with amino acid residue.