Synthesis Of Quaternary Ammonium Cationic Polymers And Studies On Their Sterilization Activities

Antibiotics have been widely used in clinical treatment for bacterial infections.However,due to the overuse of antibiotics,large numbers of drug-resistant bacteria appear,which makes antibiotics lose their original therapeutic effect and causes a serious clinical medical crisis.Therefore,it is urgent to develop new antibacterial agents to fight drug-resistant bacteria.To this end,this paper has mainly carried out the following research:1、A series of amphiphilic cationic polyacrylate polymers N1-N4 were synthesized by radical polymerization and further quaternary amination.N3 can self-assembled into positively charged nanoparticless(N3-NPs)with a diameter of 455.9 nm and a zeta potential of 33.4 m V in aqueous solution,which was confirmed by SEM and DLS.Biological activity evaluations show that N3-NPs exhibited a good bactericidal effect on both Gram-positive and Gram-negative bacteria(E.coli,P.aeruginosa,E.faecalis,VRE,and B.subtilis),with a MIC value in the range of 2-8 mg/m L and the bactericidal efficiency reached more than 94%.Most importantly,the nanoparticless did not result in resistance of the VRE and P.aeruginosa even after their 16th passages.Fluorescence staining,SEM and membrane potential studies revealed the action mechanism of the nanoparticless,that is the membrane permeability was changed by the electrostatic adsorption of N3-NPs at first,then the bacterial membranes disrupted,therefore exhibiting high efficiency and broad-spectrum antibacterial efficacy.Furthermore,N3-NPs exhibit low toxicity on mouse fibroblasts(L929).This work provides a potential way for the research and development of non-resistant and broad-spectrum antimicrobial materials.2、A quaternary ammonium salt quinine polymer with amphiphilic structure(QNDMC)has been designed and synthesized,and its structure was confirmed by ~1H NMR.Biological activity evaluations show that QNDMC had good bactericidal activity against both gram-negative bacteria(E.coli)and gram-positive bacteria(B.subtilis),with the MIC values of 2μg/m L,and the bactericidal efficiency up to 95.9%and 97.8%,respectively.Importantly,fluorescence staining,SEM and membrane potential studies have shown that QNDMC would cause a thorough and irreversible damage to the bacterial structure,thus making it is difficult for bacteria(such as E.coli)to develop drug-resistance.The QNDMC developed in this study has the advantages of simple and convenient synthetic method,high bactericidal efficiency and not causing bacterial drug resistance,etc.It would provide a new idea for the development of novel and highly efficient bactericidal polymer.