Biosynthesis And Activity Analysis Of Silver Nanoparticles From The Endophytic Fungi Of Fritillaria Cirrhosa

As a special kind of silver-based material,silver nanoparticles has different properties from conventional materials such as heat,light,electricity,magnetism,catalysis,and sensitivity.It was widely used as catalyst,antistatic,low-temperature superconducting and biosensor materials,and also in the field of biomedicine.The efficient synthesis of silver nanoparticles become a hot topic of research.In recent years,reports of biosynthesis of silver nanoparticles by various biological materials and microbes with silver nitrate have been published extensively.It has been proved that a variety of plant endophytic fungi have the function of biosynthesis of silver nanoparticles.As a valuable medicine and food dual-use Chinese herbal medicine,Fritillaria cirrhosa has the function of clearing heat,moistening the lungs,resolving phlegm,relieving cough,and dispelling the carbuncle.The endophytic fungi of Fritillaria cirrhosa is a kind of fungal species closely related to Fritillaria cirrhosa,which has great research value.Its bioactivity research also becomes a hot topic recently.In this study,the endophytic fungi of Fritillaria cirrhosa was used as the raw material to synthesize nanosilver successfully mixed with silver nitrate solution by biosynthetic method.The synthesis process was optimized by changing the reaction conditions,and then silver nanoparticles was used as the object to carry out antibacterial and anti-tumor activity.In order to provide theoretical basis for the in-depth study of biosynthesis of silver nanoparticles from endophytic fungi.The main results are as follows:1.The biosynthesis method is adopted,the endophytic fungi soaking solution was reacted with silver nitrate solution to screen the 15 isolated Fritillaria cirrhosa endophytic fungi from the early stage of the laboratory research group.The results showed that bothFritillaria cirrhosa endophytic fungi CBY4 and CBY13 were able to synthesize silver nanoparticles by biosynthetic method,and both strains were identified as Fusarium tricinctum.The silver nanoparticles they synthesized were named 4-AgNPs and 13-AgNPs.2.The effects of pH,silver nitrate solution concentration,light intensity and temperature on CBY4 and CBY13 biosynthesis silver nanoparticles were discussed respectively.The synthetic amount of silver nanoparticles shows significant differences under different conditions.In the range of pH 3-11,the synthesis of 4-AgNPs and 13-AgNPs reached the maximum at pH 6.When the concentration of silver nitrate solution was 2mmol/L,the synthetic amount of 4-AgNPs and 13-AgNPs were larger and particle size was the smallest.In the range of 2000 Lux light intensity,with the increase of light intensity,the synthesis of4-AgNPs and 13-AgNPs increased;In the range of 50? temperature,with the increase of temperature,the synthesis of 4-AgNPs and 13-AgNPs were increasing.Eventually,it was confirmed that the synthesis of 4-AgNPs and 13-AgNPs was relatively more suitable under the condition for pH of 6,2 mmol/L of the silver nitrate,2000 Lux of the light intensity and at the temperature of 50?.3.4-AgNPs and 13-AgNPs have good bacteriostasis effects on Staphylococcus aureus and Escherichia coli.The inhibition zone diameters of the plate hole diffusion method were19.33 mm and 19.97 mm,19.72 mm and 19.38 mm.The MIC of Staphylococcus aureus and Escherichia coli biofilm formed by 4-AgNPs was 76 g/mL and 38 g/mL respectively,and the MIC formed by 13-AgNPs inhibiting Staphylococcus aureus and Escherichia coli biofilms was 60 g/mL and 30 g/mL respectively.4.Silver nanoparticles 4-AgNPs and 13-AgNPs had obvious inhibition on proliferation and growth of human cervical cancer Hela cells,which could induce apoptosis of cancer cells,it indicated they had good antitumor activity.In conclusion,the endophytic fungi CBY4 and CBY13 isolated from Fritillaria cirrhosa were first found in this study to have the abilities to synthesize silver nanoparticles.An optimized reaction condition for silver nanoparticles synthesis was optimized,and the synthesis of silver nanoparticles was found to have certain antibacterial and antitumor activities.This study found new biological functions of endophytic fungi from Fritillaria cirrhosa,which also provided theoretical basis for accumulating more information for thestudy on biosynthesis of silver nanoparticles.