Soleimani Mohammad, Habibi-Pirkoohi Maziar
Department of Microbiology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran.
Avicenna J Med Biotechnol. 2017 Jul-Sep;9(3):120-125.
It is well documented that Silver Nanoparticles (SNPs) are potent antimicrobial agents. However, little is known about antimicrobial effects of biologically synthesized SNPs at molecular level. In the present study, efficacy of the green microalgae in biosynthesis of silver nanoparticles and inhibitory effect of the biosynthesized SNPs on growth and virulence of were investigated.
Algal suspension was incubated in the presence of silver nitrate to induce formation of nanoparticles. The experiment was conducted under a pH range to evaluate pH effect on the shape and properties of nanoparticles. Characterization was performed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS) and X-ray diffraction analysis (XRD). Moreover, concentration of biosynthesized SNPs was measured by high resolution ICP-OES spectrometer. Antibacterial effect of SNPs on growth of was evaluated by broth micro-dilution method. Inhibitory effect of SNPs on alpha hemolysin, a well-known virulence factor of was investigated through real time PCR assay.
Spherical SNPs were produced with characteristic monodispersity at low and neutral pHs; however, in alkaline condition, nanorod structures were formed. SNPs inhibited growth of at concentration of 50 . Alpha hemolysin expression was also effectively inhibited by SNPs treatment.
In general, results revealed formation of spherical silver nanoparticles with inhibitory effects on bacterial growth and antagonist activity on the expression of alpha hemolysin. Moreover, increase in pH to basic condition resulted in aggregation of nanoparticles and formation of rod-like nanostructures.
有充分文献记载，银纳米颗粒（SNPs）是有效的抗菌剂。然而，关于生物合成的银纳米颗粒在分子水平上的抗菌作用知之甚少。在本研究中，研究了绿色微藻在银纳米颗粒生物合成中的功效以及生物合成的银纳米颗粒对[细菌名称未给出]生长和毒力的抑制作用。
将藻类悬浮液在硝酸银存在下孵育以诱导纳米颗粒形成。在一定pH范围内进行实验以评估pH对纳米颗粒形状和性质的影响。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、能量色散光谱（EDS）和X射线衍射分析（XRD）进行表征。此外，通过高分辨率电感耦合等离子体质谱仪（ICP - OES）测量生物合成的银纳米颗粒的浓度。通过肉汤微量稀释法评估银纳米颗粒对[细菌名称未给出]生长的抗菌作用。通过实时PCR测定法研究银纳米颗粒对α - 溶血素（一种已知的[细菌名称未给出]毒力因子）的抑制作用。
在低pH和中性pH条件下产生了具有特征性单分散性的球形银纳米颗粒；然而，在碱性条件下，形成了纳米棒结构。银纳米颗粒在浓度为50[浓度单位未给出]时抑制了[细菌名称未给出]的生长。银纳米颗粒处理也有效抑制了α - 溶血素的表达。
总体而言，结果表明形成了对细菌生长具有抑制作用且对α - 溶血素表达具有拮抗活性的球形银纳米颗粒。此外，将pH提高到碱性条件会导致纳米颗粒聚集并形成棒状纳米结构。
