Biosynthesized Silver Nanoparticles Using Orange Juice Extract And Their Biocompatiblilty Study

Background:Silver nanoparticles(AgNPs)are nano-sized metallic silver simple substances.Because of their very small size,they have unique physical and chemical properties,such as antibacterial activity,electrical conductivity,and catalytic activity.Nanoparticles have some special applications,such as electrochemical applications,medical applications,wastewater treatment,etc.At present,three methods can be used to prepare silver nanoparticles:physical,chemical,and biological methods.The concept of green chemical engineering and the development of biosafety materials have made biological methods to prepare silver nanoparticles become a research hotspot and a practical need..Orange juice is a widely-sourced,edible and safe raw material.In this study,sugars,phenols,and ketones contained in orange juice extract were used as reducing agents for silver nitrate and capping agents for silver nanoparticles.During the preparation process,conditions such as pH value,temperature,and reaction time were explored and optimized.A safe,efficient,and controllable silver nanoparticle biological preparation method was designed.The biologically prepared silver nanoparticles were characterized,Further research on compatibility and antibacterial properties.This thesis mainly consists of two parts:Part one:Preparation and Characterization of Silver NanoparticlesObjective:The purpose of this study was to explore and optimize the silver nanoparticle bio-preparation process using orange juice extract,and to characterize the silver nanoparticles prepared under different conditions.Methods:Using silver juice extract to reduce silver nanoparticles from silver nitrate under different pH conditions,reaction time,and temperature conditions,silver nanoparticles were collected using a high-speed centrifuge,and the amount of output was analyzed by UV-visible spectroscopy.The particle size and surface charge of the material are characterized.The transmission electron microscope(TEM)was used to observe the size,shape and lattice structure of the prepared silver nanoparticles..Results:The yield of silver nanoparticles was the highest under the conditions of pH=8.0,0?,and reaction time of 4 h.The prepared silver nanoparticles were spherical or ellipsoidal,with an average particle size of 15.54 nm,a Zeta potential of-34.46,and good dispersion.Conclusion:The silver nanoparticle produced by using orange juice extract at pH=8.0,0?,and reaction time of 4 h has the highest yield.This kind of silver nanoparticle has small particle size,uniform dispersion,and is not easy to agglomerat.Part two:Study on Biocompatibility of Silver NanoparticlesObjective:The biocompatibility of silver nanoparticles prepared by orange juice extract was clarified.Methods:The biocompatibility and antibacterial properties of silver nanoparticles were evaluated by CCK-8 kit,scanning electron microscope and bacteriostatic experiments.The CCK-8 kit was used to detect the absorbance of the prepared silver nanoparticles on the skin fibroblasts on the back of SD suckling rats in a microplate reader;the scanning electron microscope was used to observe the morphological changes of the prepared red blood cells treated with silver nanoparticles;Changes in absorbance of Staphylococcus aureus and E.coli treated with silver nanoparticles in the plate were detected.Results:Silver nanoparticles with a concentration between 6.25-50 ?g/ml had no toxic effect on rat skin fibroblasts and red blood cells.Silver nanoparticles at a concentration of 12.5 ?g/mL and above have a significant inhibitory effect on E.coli,and silver nanoparticles at a concentration of 100 ?g/mL and below have no obvious inhibitory effect on S.aureus.Conclusions:The silver nanoparticles prepared by this method have specific antibacterial properties in a good biocompatible concentration range.