Polyethyleneimine and quaternized ammonium polyethyleneimine: the versatile materials for combating bacteria and biofilms

Abstract

Bacterial infection has become a serious clinical concern due to the emergence of drug-resistance and biofilm formation. Therefore, it is in great demand to develop efficient antimicrobial agents to treat bacterial infection without using antibiotics. Herein, we successfully prepared four quaternized ammonium PEI (QPEI: PEI₁₂₀₀-C2, PEI₁₂₀₀-C4, PEI₁₂₀₀-C6 and PEI₁₂₀₀-C8) using the commercial available PEI₁₂₀₀. Both PEI and four QPEI presented broad-spectrum antimicrobial activity against Gram-negative bacteria (E. coli, and P. aeruginosa) and Gram-positive bacteria (B. amyloliquefaciens and S. aureus), especially PEI₁₂₀₀-C6 showed the strongest antimicrobial activity with good biocompatibility at the MIC concentrations. Besides, PEI₁₂₀₀-C6 showed 4-16-fold better antibacterial effect than PEI₁₂₀₀, and fluorescent microscope imaging demonstrated that both of them could efficiently eradicate biofilms formed by four bacterial strains in vitro. As the accessible broad-spectrum antibacterial agents, PEI₁₂₀₀ and PEI₁₂₀₀-C6 are significant candidates to treat bacterial infections or eradicate biofilms on indwelling medical devices.