Nano–Bio Interaction and Antibacterial Mechanism of Engineered Metal Nanoparticles: Fundamentals and Current Understanding

The rapid development of multidrug resistance in a wide range of microorganisms poses a significant clinical challenge for healthcare professionals treating infectious diseases. Over the last decade, research has focused on the preparation of metal-based nanomaterials with antibacterial, antiviral, and antifungal activities to combat communicable diseases. Several metal nanomaterials, such as gold, copper, silver, palladium, and metal oxides, such as titanium, zinc, and iron, have demonstrated encouraging antimicrobial properties against multidrug-resistant microorganisms. The nano–bio interaction of metal nanoparticles are particularly influenced by their physicochemical properties, including shape, size, surface charge, ligand capping, doping, pH stability, roughness, and crystal structure. Once interacting, nanoparticles exert their biocidal effects through various pathways, such as enhanced intracellular reactive oxygen species, cell membrane damage, membrane potential depolarization, DNA damage, biofilm destabilization followed by interactions with biofilm components. However, a clear understanding of the connection between the specific physicochemical properties and antimicrobial mechanisms of metal nanoparticles is lacking. Thus this comprehensive review article discusses different fundamental aspects of nano–bio interactions of metal nanoparticles with planktonic as well as biofilm form of bacteria, the associated antimicrobial mechanisms along with recent advancements and therapeutic challenges.

Graphical abstract