Enhancing antibacterial activity of geminized cationic amphiphilic polymer via structure control and self-assembly regulation

Abstract

A novel geminized amphiphilic polymer containing double cationic head groups and hydrophobic tails in each structural unit (denoted as PAGBn), has been prepared in our study. The self-assembly behavior on the solid/liquid interface was investigated by quartz crystal microbalance with dissipation (QCM-D), steady-state fluorescence, dynamic light scattering (DLS) and transmission electron microscope (TEM). A two-regime buildup can be observed, where the first regime is attributed to the rapid adsorption of polymers, while a rearrangements of pre-adsorbed molecules and their aggregation on the surface dominate the second regime, exhibiting a formation of aggregates in large sizes due to the effect of the charge density and hydrophobes on the self-assembly process. It exhibits a drastically enhanced killing efficiency of ∼99.9% against both of Staphylococcus aureus and Escherichia coli bacteria for PAGBn compared with other traditional single-chained polymers, through the reinforced synergistic effect of electrostatic and hydrophobic interactions, and the formation of large-sized polymer aggregates, encompassing and killing the bacteria more efficiency. Our findings reveal the antibacterial mechanism and the correlation between antibacterial activity and aggregates structure, providing a basis for the development of super-antibacterial materials in the infection resistant applications.