Nitric oxide integrated polyethylenimine-based tri-block copolymer for efficient antibacterial activity

The work demonstrated a successful synthesis of nitric oxide (NO)-releasing material and its antibacterial effect on Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA). The polymeric support composed of thermosensitive Pluronic F68 having good biocompatibility and branched polyethylenimine (BPEI) housed N-diazeniumdiolates (NONOates) which could store and release NO under appropriate physiological condition. The developed F68-BPEI-NONOates releases a sufficient amount of NO under physiological condition to elicit effective killing of E. coli, S. aureus and MRSA. The antibacterial ability of the released NO was compared to un-treated control or unmodified F68 polymer by using confocal microscopy; F68-BPEI-NONOates demonstrated excellent antibacterial activity with in vitro low cytotoxicity. TEM investigation also revealed the destruction of bacteria membrane caused by NO. The effectiveness of F68-BPEI-NONOates against resistant strains such as MRSA provides a very simple but highly efficient strategy to combat drug-resistant bacterial infections. (C) 2013 Elsevier Ltd. All rights reserved.