Size dependent inherent antibacterial activity of polycation coated poly(lactide-co-glycolide) nanoparticles

[Display omitted] •Greater polycation quantity in PLGA NP coating resulted in larger particles.•The cationic NPs showed substantial antibacterial activity.•The antibacterial activity of the cationic NPs was dependent on their size.•The number of large particles were significantly low in killing the bacteria. Bacterial infections, which are among the global causes of death, are becoming more difficult to treat due to antibiotic resistance. Therefore, new antibacterial materials are needed to selectively target bacteria and reduce the effect of antibiotic resistance. Polycations have emerged as a promising solution due to their inherent antibacterial properties, through directly interacting with the cell wall leading to bacterial disruption. In this study, poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) were coated with cationic copolymers of 4-vinylpyridine to produce inherently antibacterial polymeric NPs. Cationic NPs (CNPs) were prepared by coating the surface of PLGA NPs with varying concentrations of the polycation to evaluate the relationship between their size and antibacterial activity. Coating PLGA NPs with polycations resulted in highly positively charged CNPs with hydrodynamic diameters between 137 and 442 nm, low polydispersity indices (