Potential non-releasing bacteria-triggered structure reversible nanomicelles with antibacterial properties

As for antifoulants containing biocides, when the effective parts releasing to the environment, the antibacterial properties will lose no matter what approach to control or trigger their releasing behaviours. Herein, inspiring from synthetic polymer systems flexibility and universality, we prepare structure changed nanomicelles by a block chitosan and poly(ethylene glycol) (CS-b-PEG) copolymer, which is without biocides releasing behaviours. Because of the difference of the solubility, PEG is coated on the CS in the alkaline environment and protect the CS. Due to protonation and deprotonation procedures of the amino groups in CS, the CS-b-PEG micelles can be triggered by bacteria directly to make the charge reversal and expose CS to kill bacteria. The results demonstrate that zeta potential is changed from + 15.87 +/- 0.64 mV in alkaline solutions to -1.96 +/- 1.09 mV in acid solutions, and the size of the micelles increases from around 30 nm to 51 nm taking about 90 min. The micelles possess outstanding antibacterial properties in acid solutions compared with the alkaline environment because of exposed CS contact with bacteria in acid solution. The CS-b-PEG micelles have outstanding antibacterial properties of S. aureus and P. aeruginosa, which are about 97.51% and 97.74%, respectively. The results of the alternate cycle in acid and alkaline solutions indicate that the nanomicelles exhibits have cycled stabilities and maintain a good bacteriostasis. The charge-reversal micelles' structure designing based on block copolymer would provide a theoretical foundation for exploring the non-releasing antifoulants in marine fields.

Automated summary

By designing charge-reversal micelles based on CS-b-PEG block copolymer, this study successfully prepared antifoulants without biocides releasing behavior, which exhibit outstanding antibacterial properties in acidic environments, providing a theoretical foundation for exploring non-releasing antifoulants in marine fields.