Non-toxic O-quaternized chitosan materials with better water solubility and antimicrobial function.

Five water-soluble O-quaternary ammonium salt-chitosans (QAS-CS) bearing N-methyl-N-R-N, N-bis(2-hydroxyethyl) ammonium bromides (R=-benzyl (chloride, BNQAS-CS), -dodecyl (C12QAS-CS), -tetradecyl (C14QAS-CS), -hexadecyl (C16QAS-CS), -octadecyl (C18QAS-CS)) were prepared, respectively. They were characterized by FTIR, (1)H NMR and elemental analysis. Through chemical modification of O-quaternized chitosans, the water solubility of all QAS-CS was improved distinctly. Their antibacterial properties indicate good antibacterial abilities against gram-positive bacteria and bad against gram-negative bacteria, therein, C12QAS-CS and C14QAS-CS are the best. More importantly, their cytotoxicity was markedly lower than the corresponding QAS monomers by evaluating for AT2 cell line using CCK-8 assay. The strategy provides a facile way to design and develop new types of antibacterial chitosan materials with better water solubility, better antimicrobial ability and lower cytotoxicity for primary additive agent of self-owned intellectual band-aids.