Engineering Nanoclay Edges to Enhance Antimicrobial Property against Gram‐Negative Bacteria: Understanding the Membrane Destruction Mechanism by Contact‐Kill

Abstract

AbstractThe overuse or abuse of antibiotics has led to serious health problems. During the recent decades, among the various methods used in antibacterial applications, some nanoclay minerals are proved antibacterial or inhibitory to the bacterial growth. However, the antibacterial mechanism of contact‐kill based on the intrinsic structure of nanoclays is still unclear. Here, the antibacterial ability of pure clay is enhanced by creating more edge surfaces on kaolinite (Kaol) and the antibacterial mechanism is clarified at the atomic level. Based on experiments and density functional theory/molecular dynamics calculations, the positively charged Al(OH) and Al(OH2) species on the edge surfaces of Kaol are confirmed to kill the Escherichia coli cells through direct contact by destroying their outer membrane (OM). The strong hydrogen bonding and van der Waals forces between OM and (110)/(10) surfaces of Kaol lead to the folding of OM. Simultaneously, the proton‐coupled electron transfer between Lipopolysaccharide (LPS) and (10) edge surface of Kaol causes the dissociation of phosphoryl groups on LPS. Considering the similarities of most nanoclayson their edge surfaces, this finding may shed some light on the development of new nanoclay‐based antibacterial materials in the future.