口腔环境响应性的银纳米颗粒对变形链球菌的抗菌作用

Antimicrobial effect of oral environmental responsive silver nanoparticles against Streptococcus pyogenes

目的开发一种基于淀粉有机模板的银纳米颗粒(silver nanoparticles,AgNPs),该AgNPs在口腔龋损酸性微环境中响应性释放,通过杀灭病原菌抑制生物膜形成和破坏已成熟生物膜的双重抗菌能力,为龋病防治提供新的思路。方法以可溶性淀粉为绿色稳定剂,抗坏血酸为还原剂,硝酸银为银前驱体,使用一锅法制备得到淀粉负载的AgNPs。通过紫外分光光度计、X射线光电子能谱和透射电镜对AgNPs的形貌和结构进行表征,采用细菌稀释平板菌落计数法探究其抗菌能力、使用结晶紫染色探究其抑制生物膜形成能力、通过细菌活死染色探究其破坏成熟生物膜能力。结果紫外分光光度计显示的特征峰和透射电镜图像均表明成功合成了均匀分散在淀粉模板的球形Ag NPs,菌落计数结果显示,在α-淀粉酶的作用下,淀粉模板酶解后释放Ag NPs,对变形链球菌具有良好的杀灭效果(P<0.001),而未经α-淀粉酶作用的淀粉负载的Ag NPs则与对照组结果相比,其差异没有统计学意义(P>0.05)。结晶紫染色结果和细菌荧光显微镜观察图像表明,淀粉负载的AgNPs具有抑制变形链球菌形成生物膜和破坏成熟生物膜的作用。结论使用简单的一锅法绿色合成的淀粉负载的Ag NPs,能在口腔中α-淀粉酶的作用下被释放,杀灭变形链球菌、抑制变形链球菌生物膜的形成,同时还能破坏成熟的生物膜,具有良好的抗菌性能。

Objectives This study aims to develop silver nanoparticles(Ag NPs)based on starch organic templates that can release responsively in the acidic microenvironment of oral caries,providing a dual antibacterial capability by killing pathogenic bacteria,inhibiting biofilm formation,and disrupting matured biofilms,which provide new insights into caries prevention and treatment.Methods Starch-loaded Ag NPs were prepared by the one-pot method,using soluble starch as a green stabilizer,ascorbic acid as a reducing agent,and silver nitrate as a silver precursor.The morphology and structure of Ag NPs were characterized using UV-Vis spectrophotometer,X-ray photoelectron spectroscopy,and transmission electron microscopy.Utilizing the bacterial dilution plate colony counting method to assess its antibacterial efficacy,employing crystal violet staining to evaluate its ability to inhibit biofilm formation,and utilizing bacterial live-dead staining to investigate its potential for disrupting mature biofilms.Results The characteristic peaks shown by the UV-vis spectrophotometer and the transmission electron microscopy images indicated the successful synthesis of uniformly dispersed spherical Ag NPs within a starch template.The colony count results demonstrated that under the effect ofα-amylase,the starch template was hydrolyzed to release Ag NPs,which exhibited excellent bactericidal effects against Streptococcus mutans(P<0.001).In contrast,there was no statistically significant difference in results between the starch-loaded Ag NPs composite withoutα-amylase treatment and the control group(P>0.05).Crystal violet staining results and bacterial fluorescence microscopy images indicated that starch-loaded Ag NPs possessed inhibitory effects on biofilm formation and disruption of mature biofilm formation.Conclusion Starch-loaded Ag NPs synthesized using a simple one-pot green method can be released in the oral cavity under the action ofα-amylase,effectively killing Streptococcus mutans and inhibiting the formation of biofilms by Streptococcus mutans.Additionally,starch-loaded Ag NPs can disrupt mature biofilms,demonstrating excellent antibacterial properties.