Precise Oligomer Organization Enhanced Electrostatic Interactions for Efficient Cell Membrane Binding.

Efficient binding of cell membranes onto nanomaterials is essential for biomedical applications such as diagnostics and cellular engineering. We find that fine control over oligomer orientation led to enhanced electrostatic interactions with the cell membrane and improved cell membrane capture. Specifically, we designed polycation oligomers incorporating positively charged imidazole heads and alkyl tails synthesized through the reversible addition-fragmentation chain transfer (RAFT) reaction. These oligomers spontaneously self-assemble through head-to-head π-π interactions, and their spatial arrangement markedly accelerates the interaction with negatively charged cell membranes. Experimental results indicate that these oriented oligomers produce a large decrease in the time required to kill bacteria compared to unmodified nanostructures (3 min versus 100 min). This is attributed to locally concentrated electrostatic attraction, which enhances the attraction between nanostructures and negatively charged cell surfaces. Our findings suggest that molecular orientation control could be a promising approach to enhancing interactions between biomaterials and live cells.