Fig. 4: PBGProOx₂₀ binds more strongly with phosphatidylglycerol to damage bacterial membranes.

a The structure of amine-functionalized, guanidine-functionalized and biguanide-functionalized poly(2-oxazoline)s with propyl spacer arm. b Cytoplasmic membrane depolarization of S. aureus and E. coli after 30-min treatment with PNProOx₂₀, PGProOx₂₀ and PBGProOx₂₀ at different concentrations (n = 3). c Zeta potential of S. aureus and E. coli before (the controls) and after 30-min treatment with PNProOx₂₀, PGProOx₂₀ and PBGProOx₂₀ at different concentrations (n = 3). d Membrane fluidity of S. aureus and E. coli before (the controls) and after 2-h treatment with PNProOx₂₀, PGProOx₂₀ and PBGProOx₂₀ at different concentrations (n = 3). e The dissipated ΔpH in S. aureus and E. coli before (the controls) and after 2-h treatment with PNProOx₂₀, PGProOx₂₀ and PBGProOx₂₀ at different concentrations (n = 3). f MIC changes of PBGProOx₂₀ against S. aureus and E. coli in the presence of different membrane phospholipids. g The UV–vis spectra of PBGProOx₂₀ titrated with phosphatidylglycerol (PG). h ITC analysis of the interaction between poly(2-oxazoline)s with different positively charged moieties and phosphatidylglycerol (PG). i Potassium ion leakage from large unilamellar vesicles (LUVs) with varying phospholipid compositions after 30min-treatment with PBGProOx₂₀ at different concentrations (n = 3). Data are mean ± SD in b–e, i. Statistical analysis was conducted using two-tailed t-test in b–e, i. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001. Exact p values are provided in Source Data.