One-Step,Painting-Like Coating Procedures To Make Surfaces Highly and Permanently Bactericidal

摘要

Previously we found that covalent attachment of long-chained,moderately hydrophobic polycations to surfaces of solid objects renders the latter permanently bactericidal.Herein we replaced such surface-specific,multistep immobilization techniques with a single-step,general procedure akin to common painting.Glass or polyethylene slides were briefly dipped into organic solutions of certain optimally hydrophobic N-alkyl-PEI (where PEI stands for branched 750-kDa polyethylenimine) polycations,followed by solvent evaporation.The resultant polycation-coated slides were able to kill on contact all of the encountered bacterial cells,whether the Gram-positive human pathogen Staphylococcus aureus or its Gram-negative brethren Escherichia coli.This biocidal effect was found not to be caused by N-alkyl-PEI molecules leached from the surface.Further examination of the mechanism of this bactericidal action suggested that the surface-deposited N-alkyl-PEI kills bacteria by rupturing their cellular membranes.This conclusion was further supported by studies in which the molecular weight of PEI and the hydrophobicity of the alkyl moiety were varied.