Polymer chain-length mediated regulation of liposome-bacteria interactions for selective targeting of gram-negative...

Polymer-functionalized liposomes offer enhanced colloidal stability and enable tunable interactions with biomolecules. In particular, such liposomes have shown great promise in targeting bacterial biofilms, making them highly attractive platforms for biomedical applications. In this study, we have investigated how variations in the molecular weight of the polymer functionalization of the liposomal surface influence their interactions with the bacterial membranes. Specifically, distearoylphosphatidylcholine-poly(methacryloylphosphorylcholine) (DSPE-pMPC)-functionalized, antibiotic-loaded liposomes with different polymer chain lengths were evaluated against both gram-positive and gram-negative bacteria. Antibacterial assays, mechanistic studies and electron microscopy analysis demonstrate that liposomes stabilized with higher molecular weight pMPC exhibit significantly enhanced interaction with gram-negative bacterial membranes leading to much greater bacterial targeting efficiency. These findings highlight that tuning the pMPC chain length is an effective strategy to improve liposome-bacteria interactions and antibacterial performance.