Interfacial interaction of zinc ions functionalized kaolinite for regulating antibacterial performance and cytotoxicity

The increasing prevalence of antimicrobial resistance (AMR), particularly among Gram-negative organisms, has led to a significant challenge in treating infections with antibiotics. Despite the long-term efforts to explore antibacterial agents or drugs, potentiating antibacterial activity while minimizing toxicity to human health remains a significant challenge. In this study, zinc-kaolinite composites were prepared using the calcination method to achieve effective and selective antibacterial activity while maintaining non-toxicity to mammalian cells. The interfacial interactions between kaolinite and zinc ions resulted in the immobilization of the latter by cation-π interaction and polar interactions. This led to a disordered structure and different geometrical configurations at the interface, with the spatial coefficient of the zinc ions changing from 0.64 to 2.08. Furthermore, the interfacial interactions regulate the intrinsic mobility and dissolution rates of zinc ions in solution, resulting in the controlled release of zinc ions. Moreover, a well-oriented structure and steady-flow rheological behaviors enable zinc-kaolinite composites to search for bacteria, thereby achieving selective antibacterial activity. The release behavior of zinc ions at the site of the bacterial surrounding environment significantly reduces toxicity and side effects. The comprehensive investigation of interfacial interaction and antibacterial performance provides new perspectives for the development of metal ion-based antibacterial materials in public health environments.