Deepa Kannan, Panda Tapobrata
J Nanosci Nanotechnol. 2014 May;14(5):3455-63. doi: 10.1166/jnn.2014.8247.
The addition of varying concentrations of precursor gold salt to different cellular fractions of Fusarium oxysporum, viz., the culture filtrate and the intracellular extract obtained in the growing and resting phase of the cells had a profound influence on the size, shape, and state of aggregation of the nanoparticles. Multiply-twinned nanoparticles were obtained when the culture filtrate was used for synthesizing nanoparticles while mostly irregular shapes were obtained with the intracellular extract. The time taken for the formation of gold nanoparticles in the culture filtrate of resting cells was very less (< 30 min) while it took more than 8 h when the intracellular extract was used for synthesis of nanoparticles. There was a reduction in size of the nanoparticles with decreasing concentration of the gold salt from 1 mM to 0.05 mM. With the intracellular extract, the initial rate of increase in surface plasmon absorption maximum was linearly proportional to the initial concentration of the gold salt used. Gold nanoparticles were also obtained with the heat-inactivated culture filtrate which suggests alternatively the role of peptides and amino acids besides proteins in reducing and/or stabilizing the nanoparticles.
向尖孢镰刀菌不同细胞组分（即细胞生长和静止期获得的培养滤液和细胞内提取物）中添加不同浓度的前体金盐，对纳米颗粒的大小、形状和聚集状态有深远影响。当使用培养滤液合成纳米颗粒时可获得多重孪晶纳米颗粒，而使用细胞内提取物时大多获得不规则形状。静止细胞培养滤液中形成金纳米颗粒所需时间非常短（<30分钟），而使用细胞内提取物合成纳米颗粒时则需要超过8小时。随着金盐浓度从1 mM降至0.05 mM，纳米颗粒尺寸减小。对于细胞内提取物，表面等离子体吸收最大值的初始增加速率与所用金盐的初始浓度呈线性比例关系。用热灭活的培养滤液也可获得金纳米颗粒，这表明除蛋白质外，肽和氨基酸在还原和/或稳定纳米颗粒中也发挥作用。
