Study On The Inhibitory Effects And Mechanisms Of Glycyrrhizic Acid Modified Gold Nanoparticles And Curcumin Modified Copper Clusters On The Proliferation Of PRRSV

The virus epidemic not only seriously endangered human health,but also caused huge economic losses.The development of antiviral drugs was one of the main means to control the virus epidemic.Metal nanomaterials had antiviral activity and good biocompatibility which were expected to develop into a new generation of antiviral drugs in the future.How to further improve the antiviral effect of metal nanomaterials was a key issue that needed to be resolved.In this thesis,the active ingredients of traditional Chinese medicine（glycyrrhizic acid（GA）,curcumin（Cur））were used as modification reagents to synthesize glycyrrhizic acid-modified gold nanoparticles（GA-Au NPs）and curcumin-modified copper clusters（Cur-Cu NCs）.On this basis,using Porcine Reproductive and Respiratory Syndrome Virus（PRRSV）as a model virus,the cytotoxicity and antiviral effects of GA,GA-Au NPs,Cur,and Cur-Cu NCs were explored.The details were as follows:1.The water-soluble GA-Au NPs were synthesized by one-pot method using GA and chloroauric acid（HAu Cl₄）as raw materials.The experimental conditions were optimized to investigate the influence of reaction time and temperature on the morphology and size of GA-Au NPs.Utilizing ultraviolet-visible（UV-vis）absorption spectroscopy and other technologies for chemical characterization of GA-Au NPs.Using MARC-145 as the cell model and PRRSV as the virus model to compare the cytotoxicity and anti-PRRSV effects of GA-Au NPs under different synthetic conditions and explored the effects of GA-Au NPs on the proliferation of PRRSV and the inhibitory mechanism by MTT,plaque test,western blot（WB）and other methods.The results showed that GA-Au NPs synthesized at a reaction temperature of 100°C and a reaction time of 1.5 h had a better antiviral effect.The GA-Au NPs synthesized under this condition had a characteristic absorption at 529 nm and the size was 15.5±3.8 nm.The raw material GA and unmodified Au NPs at the same concentration had no significant anti-PRRSV effect.GA-Au NPs had inhibitory effects on the adsorption,invasion,replication,and release of PRRSV.The research results will provide a certain reference for the development of new antiviral drugs.2.The water-soluble Cur-Cu NCs were synthesized by one-pot method using Cur as a reducing agent,and chemically characterized by UV-vis absorption spectroscopy,etc.It emited bright blue fluorescence under ultraviolet irradiation of 365 nm,and the maximum emission wavelength was at 449 nm.Cur-Cu NCs were uniformly distributed and spherical,with an average particle size of 7.90 nm.The cytotoxicity of Cur-Cu NCs and Cur to MARC-145 was compared by MTT test.The results showed that when the cells were treated with 15.0μg/m L Cur for 12 h,the cell survival rate was below 20%.However,after treating cells with the same concentration of Cur-Cu NCs for 48 h,the cell survival rate was still more than 85%.The same concentration of Cur-Cu NCs and Cur were selected for indirect immunofluorescence assay（IFA）,and it was found that Cur-Cu NCs has better anti-PRRSV activity than Cur.New perspectives of further investigation on using high-cytotoxic Chinese herbal medicine in the field of antivirus had been put forward based on the above consequences.