Quercetin Loaded Metal Nanoparticles For Preparation And Antibacterial Activity Study

Infections are serious problems in our society.The expansion of antibiotic resistance is a growing menace today due to the indiscriminate use of antibiotics.It has resulted in the proliferation of selective pathogenic bacteria which are resistant to multiple drugs.It is leading to an urgent requirement for new antibacterial drugs and alternatives.Interest on the potential health benefits of dietary flavonoids has grown because they have been related to a reduced risk of different chronic diseases.Quercetin acts as an effective inhibitor of xanthine oxidase and lipoxygenase,which play important roles in inflammation,atherosclerosis,cancer,and aging.Quercetin has extremely low water solubility,which is a major factor in drug absorption.So quercetin needs to be modified and transferred to the other molecules in order to change the polarity.Quercetin oral bioavailability is poor which hinders its wide application in biomedical research.Currently,investigators focus nanoparticle research on recognition,sensing,imaging,and delivery in biological systems with a broad range of core materials 1 Quercetin loading CdSe/ZnS nanoparticles: characterization,fluorescence and antibacterial evaluationsWe described a simple method for synthesis of Qe/CdSe/ZnS nanoparticles(QCZ NPs).The QCZ NPs had an average diameter of 10 nm.We investigated the antibacterial activity of QCZ NPs against drug-resistant Escherichia coli(E.coli)and Bacillus subtilis(B.subtilis)in vitro.Results showed that QCZ NPs had considerably more effective antibacterial activities than Qe or CdSe/ZnS nanoparticles.SEM and AFM studies reveal cell membrane damage in QCZ NPs-treated cells.Antibacterial studies reveal that QCZ NPs act against E.coli and B.subtilis by disrupting the bacterial cell wall and membrane.Nucleic acid and cellular soluble proteins decrease with the concentration of QCZ NPs.The QCZ NPs is a potential nanoscaled drug for bacteria.2 Investigation of silver nanoparticle-decorated quercetin as potent antibacterial activityThe potential application of silver nanoparticles(AgNPs)in antibacterial has become an important research field.The CFU assay suggested that the Qe-AgNPs(QA NPs)had more pronounced antibacterial effects than Qe and AgNPs.Characterization experiment indicated that that QA NPs with a diameter of approximately 10 nm were uniformly.The SEM image show the Qe surround the QA NPs.QA NPs showed highly effective antibacterial activities against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus).Fluorescence microscopy assay demonstrated that individually dispersed QA NPs had high antibacterial activity.Mechanisms of cell integrity study through change of cell membrane,wall and enzyme by SEM,TEM and ONP experiments.Disruption of nucleic acids was the direct embodiment for inhibit bacteria effect.In vivo studies demonstrate that QA NPs was a potential biomaterials drug for S.aureus caused bacteraemia model.Through the results of biodistribution of bacteria and pathological examination of animal organ and tissues,the bacteria in blood and organs,and inflammation cell in tissues were gradually decreasing after the mice were intravenous tail injections with QA NPs for treatment.The results of cytotoxicity of QA NPs suggested that it could be a promising antibacterial agent with low toxicity to mice cells.Both in vitro and in vivo studies demonstrate that QA NPs is a potential nanoscaled drug for E.coli and S.aureus.3 Silver nanoparticles-quercetin conjugation to siRNA against drug-resistant bacteria study.RNA interference has considerable therapeutic potential because of its high specificity and potential capability to evade drug resistance.Characterization experiment indicated that the diameter and dispersion of siRNA/AgNPs–Qe and the siRNA release of experment.Results of the in vitro study suggested that siRNA/AgNPs–Qe could destroy the cell wall and inhibit bacterial propagation.Meanwhile,the in vivo experiment on the animal bacteremia model,as well as the optical imaging of nude mice and their isolated organs,demonstrated that bacteria accumulated in the blood,heart,liver,spleen,lungs,and kidneys after the intravenous injection of B.subtilis.The bacteria in the blood and organs,as well as the inflamed cells in the tissues,gradually decreased after the mice received intravenous tail injection of siRNA/AgNPs–Qe for treatment.Both the in vitro and the in vivo studies exhibit that siRNA/AgNPs–Qe can be a potential nanoscale drug delivery system for B.subtilis targeting bacterimia.