We report a role-switching method for preparing ultrafine water-dispersible silver nanoparticles with long-term stability based on a soft deformable block copolymer vesicle. Those ultrafine silver nanoparticles showed excellent antibacterial efficacy against both Gram-negative and Gram-positive bacteria with quite low minimum inhibitory concentrations (MICs) of 16.9 μg mL−1 and 8.45 μg mL−1, respectively.
