Green Synthesis Of Ag Nanoparticles And Research On Their Antibacterial Properties

In recent years,the spread of bacteria has seriously affected people’s health.Facing the endless stream of drug-resistant bacteria,the development of new antibacterial materials is imminent.The widespread sterilization properties of nano-materials have received great attention.Among them,Ag nanoparticles（Ag NPs）are the most widely used nano-sterilization materials.In this paper,Ag NPs were prepared by green synthesis method,the reaction mechanism of green synthesis Ag NPs was analyzed,and the growth factors affecting noble metal nanoparticles were explored.At the same time,this paper also tested the antibacterial properties of green synthetic Ag NPs,and explored the bactericidal mechanism of Ag NPs.The main research contents are as follows:（1）Green synthesis of Ag NPs.Using AgNO₃ as the silver source and Ginkgo biloba extract as the reducing agent and coating agent,Ag NPs were prepared by a green chemical synthesis method.The prepared Ag NPs have uniform particle size distribution and good monodispersity.With the help of FTIR,UV-vis and other testing methods,the growth mechanism of Ag NPs was analyzed,and the influence of the composition,reaction temperature,reaction time and other factors of Ginkgo biloba extract on the morphology and size of the particles was analyzed.The size of the synthesized Ag NPs is between 10-20 nm.（2）Antibacterial performance test of Ag NPs.Based on the prepared green nanoparticles,this paper studies the antibacterial properties of Ag NPs.The results showed that Ag NPs had significant antibacterial activity.The minimum inhibitory concentration（MIC）of Ag NPs against Escherichia coli and Pseudomonas aeruginosa was 0.044μg/m L and 0.088μg/m L,respectively.Ag NPs also have good bactericidal properties against drug-resistant Pseudomonas aeruginosa（MIC is 0.044μg/m L,MBC is 0.088μg/m L）.The antibacterial properties of the green synthetic Ag NPs far exceed the existing reports（MIC is 20μg/m L）.In addition,through the measurement of TEM and endogenous reactive oxygen species（ROS）levels,quantitative real-time reverse transcription polymerase chain reaction（q RT-PCR）,the antibacterial mechanism of Ag NPs was systematically analyzed.（3）Preparation of Ag NPs self-assembled films.Based on the green synthesis of Ag NPs,the monodispersity is better.In this paper,a liquid phase film-forming system was constructed,and a single-layer Ag NPs self-assembled film was prepared.The Ag NPs self-assembled film substrate is used for the detection of Rhodamine（R6G）dye molecule,and its detection limit can reach 10^-7mol/L.