Studies On The Biosynthesis Of Metal Nanoparticles By Fungi And Their Appliactions

The combination of nanotechnology and biotechnology has made significant progress in interdisciplinary fields and is moving forward at an unpredictable pace.In a sense,nanotechnology is more like the operation of atoms or molecules at the nanometer level,mining the nature of the material not found,and then develop its new features of the technology.The emergence of nanotechnology,making the metal material in size smaller,this change not only retains the good characteristics of the metal itself,but also in the application of a qualitative leap.As the nano-particles have small size effect,surface effect,quantum effect,macroscopic quantum tunneling effect and catalytic effect,it has many aspects in catalysis,optics,electrical engineering,biology,magnetism,enhanced toughness,hydrogen storage performance,lubricating performance and medicine.Its special features.At present,the metal nanoparticles synthesis methods are mainly three: chemical,physical and biological methods.With the popularity of green and environmentally friendly concepts,the use of biological systems to synthesize metal nanoparticles of biological methods of concern.Biological methods are environmentally friendly methods,which are cheap,sustainable,responsive to reaction conditions,product size control,and no use of stimulated,toxic chemicals.From simple prokaryotes to complex eukaryotes,these organisms are likely to be used to synthesize nanoparticles.And these organisms are mainly three categories of "members" : plants,bacteria and fungi.Compared to plants and bacteria,fungi can secrete rich metabolites and a variety of enzymes,and has become a biological synthesis of nanoparticles one of the main force.In the precious metals,silver and gold nanoparticles are the most common nanoparticles,and are used in many fields,including optics,catalysis,environmental protection and medicine,due to their own special properties.The aim of this study is to isolate the fungi from the environment(soil and plant),and to exert the specialty of its metabolites,and excavate the fungi with the biosynthesis activity of metal nanoparticles.Moreover,by optimizing the biosynthesis process,the best conditions for the use of fungal biosynthetic metal nanoparticles are obtained.In this study,the use of fungal biosynthetic silver and gold nanoparticles(ie,nano-silver and nano-gold)was mainly discussed,and its application in medical field was studied.In this study,145 strains and 135 strains of fungi were isolated from 8 soil samples and 18 plant samples(from 6 kinds of plants),respectively.Twenty-two strains of 22 strains with nano-silver or gold biosynthetic activity were screened from the above 280 strains.Strain S6-6(synthetic nano-silver)and HB-8(both synthetic nano-silver,but also synthetic nano-gold)biosynthetic ability is strong,and has not yet appeared related reports.The use of morphological and molecular biology combined method to identify unknown strains is the most commonly used and most common research methods.This study also used the method to identify the results: strain S6-6 was Arthroderma fulvum and strain HB-8 was Cylindrocladiella peruviana.Biosynthesis of nano-silver using strain S6-6: The optimum conditions for the incubation were as follows: the inoculation amount of the cells was 4g and the incubation time was 8h.The optimum conditions were as follows: the concentration of Ag NO3 was 1.5m M,The reaction temperature was 55 °C,and the reaction time was 10 h.The biosynthesis of nano-silver was characterized by TEM,XRD and particle size analysis.The results showed that the nano-silver was spherical or near-spherical with a particle size of 20.56 nm,with a face-centered hexahedral crystal structure.Antimicrobial studies on biosynthesis of nano-silver: Microinjection of antimicrobial susceptibility test showed that biosynthesis of nano-silver was effective for all tested strains,the MIC in the range of 0.125~4?g/ml.Fluconazole has an antibacterial effect against Candida(MIC is 0.250~16.0?g/ml)and is not effective against Aspergillus and Fusarium(MIC> 64.0?g/ml).Itraconazole is effective against Fusarium(MIC> 16.0?g/ml)and is effective against Candida and Aspergillus(MIC is 0.030~0.250?g/ml).Compared with fluconazole and itraconazole,biosynthesis of nano-silver has a broader antibacterial spectrum.Chessboard dilution method combined with drug susceptibility test showed that: acting on Candida albicans,biosynthesis of nano-silver and fluconazole or itraconazole two antifungal agents for the role of the role of Aspergillus fumigatus,biosynthesis of nano-silver And itraconazole addition,but with the performance of fluconazole has nothing to do.The XTT reduction method showed that the inhibitory rate of Candida albicans and Aspergillus fumigatus biofilm was about 50% when the concentration of biosynthetic nano silver was 2.00?g/ml and 1.00?g/ml.Biosynthesis of nano-silver can inhibit the production of Candida albicans and Aspergillus fumigatus biofilm;also concluded that biofilm-immobilized cells are more resistant to drug concentrations than planktonic cells.The results of ultrastructural analysis showed that the biosynthesis of nano-silver destroyed the integrity of Candida albicans and Aspergillus fumigatus biofilm.Nanoparticles could play an antifungal role by affecting the cell wall of fungi.Biosynthesis of nano-silver and gold using strain HB-8: The optimum conditions for the synthesis of nano-silver were as follows: the inoculation amount of the compound was 4g,the incubation time was 6h,the rotational speed was 120 rpm,the concentration of the substrate Ag NO3 was 2.0m M,the reaction temperature was 35 °C and the reaction time was 8h.The optimum conditions for the synthesis of nano-gold were as follows: the inoculation amount was 3g,the incubation time was 8h,the rotational speed was 180 rpm,the concentration of the substrate HAu Cl4 was 1.0m M,the reaction temperature was 25°C,reaction time 6h.The biosynthesis of nano-silver and gold was characterized by TEM,XRD,FTIR and particle size analysis.The silver nanoparticles with particle size of about 62.18 nm were obtained,and the gold nanoparticles were 47.13 nm.And the possible reason why the synthesized nanoparticles can be stably present is that the surface of the nanoparticles is wrapped with protein or carbohydrate.Biosynthesis of nano-gold for HCG test strip: In this study,human chorionic gonadotropin(HCG)test strips were prepared using colloidal gold(bio-gold and chemical gold),and several important properties of the two HCG test strips were evaluated and analyzed,including sensitivity,specificity,repeatability,HOOK effect and stability.From the test results concluded: The sensitivity of the bio-gold and chemical test strips is 15 m IU/ml and 20 m IU/ml,respectively,indicating that the bio-gold test strip has a higher sensitivity;Both test strips have good specificity and repeatability,and no HOOK effect.During the stability test,the thermal stability of the two test strips was investigated.Under the condition of 37°C,the bio-gold test strip can be stored for at least 35 days to maintain its stable performance,which is shown as a positive result,while the chemical gold test strip can be stored for at least 28 days,indicating that the thermal stability of the bio-test strip it is better.In addition,in the several important performance tests,in the specificity,repeatability and HOOK effect,the two test strips no significant difference,and in the sensitivity and stability,compared to the chemical gold test strips,bio-gold Test strips show better results.In summary,this study not only explores fungi(Arthroderma fulvum and Cylindrocladiella peruviana)with biosynthetic metal nanoparticle activity,but also reveals that biosynthesis of nano-silver plays an important role in antifungal fields due to its unique properties,and provides the theoretical basis and technical support for biosynthesis of nano-gold for immunochromatography and other detection techniques.