载银氧化壳聚糖的制备与抑菌性能研究

Research on Antibacterial Activity of Silver-Carried Oxidized Chitosan

为制备一种高效抑菌剂,以壳聚糖(chitosan,CS)为原料,采用漆酶/2,2,6,6-四甲基哌啶-1-氧自由基(2,2,6,6-tetramethylpiperidine-1-oxyl,TEMPO)体系制备6-羧基壳聚糖(6-carboxyl chitosan,C-COS),然后与硝酸银反应制备载银氧化壳聚糖(silver-carried oxidized chitosan,C-COS-Ag),对其抑菌性能进行研究。结果表明,与CS相比,C-COS-Ag的抑菌效果明显提高,其对大肠杆菌和金黄色葡萄球菌的抑菌圈直径分别为(22.75±1.50)和(13.75±2.50)mm,最小抑菌质量浓度均为6.10μg·mL^(-1)。细菌生长曲线试验证实,C-COS-Ag能明显降低大肠杆菌和金黄色葡萄球菌的生长速率;细胞内容物渗透试验表明,C-COS-Ag能够破坏细菌的细胞膜和细胞壁形态,导致核酸、蛋白质等大分子物质渗出,碱性磷酸酶活性上升,β-半乳糖苷酶活性下降,半乳糖合成途径受阻,细菌正常代谢受到影响。以上研究结果为C-COS-Ag的应用提供了理论依据。

In order to prepare a highly effective antibacterial agent,chitosan(CS)was used as raw material to prepare 6-carboxyl chitosan(C-COS)by laccase/2,2,6,6-tetramethylpiperidine-1-oxyl radical(TEMPO)system,and then the silver-carried oxidized chitosan(C-COS-Ag)was prepared by reaction with silver nitrate.The antibacterial activity of C-COS-Ag was studied.The results showed that the antibacterial effect of C-COS-Ag was significantly improved compared with CS.Its inhibitory zone diameters against Escherichia coli and Staphylococcus aureus were(22.75±1.50)and(13.75±2.50)mm,respectively,with a minimum inhibitory concentration of 6.10μg·mL^(-1)。The bacterial growth curve test confirmed that C-COS-Ag could significantly reduce the growth rate of Escherichia coli and Staphylococcus aureus;the penetration test of cell contents showed that C-COS-Ag could destroy the cell membrane and cell wall morphology of bacteria,resulting in the exudation of nucleic acids,proteins and other macromolecules,the increase of alkaline phosphatase activity,the decrease ofβ-galactosidase activity,the obstruction of galactose synthesis pathway,and the normal metabolism of bacteria were affected.Above results provided a theoretical basis for the application of C-COS-Ag.