N-halamine terpolymer antibacterial nanohemisphere with amphiphilic and rigid-flexible groups

Conventional N-halamine precursor polymers with excess hydrophilic/hydrophobic and rigid/flexible groups have failed to achieve a co-balanced effect of amphiphilicity and rigidity-flexibility. To overcome this problem, hydantoin terpolymer nanohemispheres (P(AMH-St-BA)NHs) were synthesized by regulating both hydrophilic/hydrophobic and rigid/flexible group ratios to 1:1 using emulsion polymerization. Thereafter, a novel N-halamine terpolymer nanohemisphere (P(ClA-St-BA)NHs) with antibacterial activity was fabricated through chlorination treatment. Interestingly, chlorinated nanohemispheres were more dispersed and regularly shaped. Moreover, the effective chlorine content (Cl + ) of P(ClA-St-BA)NHs was detected to be 1.1 % by iodometric/thiosulfate titration, and the existence of N-Cl bonds was supported from the color change of titration. In vitro cytotoxicity suggested that P(AMH-St-BA)NHs possessed superior biocompatibility and safety. Additionally, the antimicrobial performance of samples with three various morphologies was investigated, discovering that the antibacterial rates of P(ClA-St-BA)NHs up to 89.5 % and 93.5 % against E. coli and S. aureus , respectively, exhibited a stronger antimicrobial capability than membranous and porous N-halamine copolymers, which reveals that their special shape elevates the property. In parallel, the antibacterial mechanism of nanohemispheres was also explored, and it was recognized that indirectly released Cl + synergizes with direct contact of N-Cl bonds for antibacterial purposes. By designing nanohemispheres, this method helps to provide new thoughts for realizing the co-balancing effects of hydrophilicity/hydrophobicity and rigidity/flexibility.