Cross-linked branched polyethylenimine used as a nitric oxide donor for prolonged nitric oxide release.

In order to prolong NO release and enhance the antibacterial effect, N-Carboxy propionyl chitosan sodium (CPCS) was cross-linked to branched polyethylenimine (bPEI) (CPCS-bPEI) and used as a NO donor. The CPCS-bPEI has been successfully synthesized at different molar ratios of CPCS to bPEI, followed with the reaction with NO gas under a parr high-pressure reactor to yield CPCS-bPEI-NO. Successful preparation of CPCS-bPEI-NO was confirmed by elemental analysis, FITR and SEM. The effective release of NO was determined by in vitro release. The antibacterial assay showed that CPCS-bPEI-NO can effectively inhibit Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). We found that the NO loading amount and antibacterial effect can be adjusted by the molar ratio of CPCS to bPEI, and there was no significant toxicity of CPCS-bPEI-NO, suggesting that it may serve as an ideal antimicrobial agent.