Vigneshwaran Nadanathangam, Kathe Arati A, Varadarajan Perianambi V, Nachane Rajan P, Balasubramanya Rudrapatna H
Nanotechnology Research Group, Central Institute for Research on Cotton Technology, Adenwala Road, Matunga, Mumbai 400 019, India.
Langmuir. 2007 Jun 19;23(13):7113-7. doi: 10.1021/la063627p. Epub 2007 May 23.
A simple route for the synthesis of silver-protein (core-shell) nanoparticles using spent mushroom substrate (SMS) has been demonstrated in this work. SMS exhibits an organic surface that reduces silver ions and stabilizes the silver nanoparticles by a secreted protein. The silver nitrate solution incubated with SMS changed to a yellow color from 24 h onward, indicating the formation of silver nanoparticles. The purified solution yielded the maximum absorbance at 436 nm due to surface plasmon resonance of the silver nanoparticles. X-ray analysis of the freeze-dried powder of silver nanoparticles confirmed the formation of metallic silver. Transmission electron microscopic analysis of the samples showed a uniform distribution of nanoparticles, having an average size of 30.5 +/- 4.0 nm, and its corresponding electron diffraction pattern confirmed the face-centered cubic (fcc) crystalline structure of metallic silver. The characteristic fluorescence of the protein shell at 435 nm was observed for the silver nanoparticles in solution, when excited at 280 nm, while Fourier transform infrared (FTIR) spectroscopy confirmed the presence of a protein shell. The silver nanoparticles were found to be stable in solution for more than 6 months. It is observed that the reducing agents from the safflower stalks caused the reduction of silver ions while protein secreted by the fungus stabilized the silver nanoparticles. These silver nanoparticles showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) and Klebsiella pneumoniae (Gram negative), in spite of the presence of an organic layer as a shell. Apart from ecofriendliness and easy availability, "SMS" as a biomanufacturing unit will give us an added advantage in ease of handling when compared to other classes of microorganisms.
在这项工作中，已经展示了一种使用废弃蘑菇基质（SMS）合成银 - 蛋白质（核壳）纳米颗粒的简单方法。SMS具有有机表面，该表面通过分泌的蛋白质还原银离子并使银纳米颗粒稳定。与SMS一起孵育的硝酸银溶液从24小时起变为黄色，表明银纳米颗粒的形成。由于银纳米颗粒的表面等离子体共振，纯化后的溶液在436nm处产生最大吸光度。银纳米颗粒冻干粉末的X射线分析证实了金属银的形成。样品的透射电子显微镜分析显示纳米颗粒均匀分布，平均尺寸为30.5 +/- 4.0nm，其相应的电子衍射图案证实了金属银的面心立方（fcc）晶体结构。当在280nm激发时，在溶液中观察到银纳米颗粒在435nm处蛋白质壳的特征荧光，而傅里叶变换红外（FTIR）光谱证实了蛋白质壳的存在。发现银纳米颗粒在溶液中稳定超过6个月。观察到来自红花茎的还原剂导致银离子的还原，而真菌分泌的蛋白质使银纳米颗粒稳定。尽管存在作为壳的有机层，但这些银纳米颗粒对两种代表性细菌金黄色葡萄球菌（革兰氏阳性）和肺炎克雷伯菌（革兰氏阴性）显示出优异的抗菌活性。除了生态友好和易于获得之外，与其他类别的微生物相比，“SMS”作为生物制造单元在易于处理方面将给我们带来额外的优势。
