Centre for Nano-Biotechnology, School of Bio-Sciences and Technology, VIT University, Vellore 632014, India.
Water Res. 2011 Oct 15;45(16):5184-90. doi: 10.1016/j.watres.2011.07.024. Epub 2011 Jul 23.
The stability of commercial silver nanoparticles (SNPs) in aquatic environment plays a significant role in its toxicity to the environment and to human health. Here, we have studied the impact of bacterial exopolysaccharides (EPS) to the stability of engineered SNPs. When nanoparticles are present in neutral water, the nanoparticles exhibited low zeta potential and are least stable. However, in the presence of EPS (10-250 mg/L), the negative surface charge of nanoparticles increased and therefore the propensity of nanoparticles to aggregate is reduced. In UV-visible spectroscopic analysis a decrease in absorbance at plasmon peak of SNPs (425 nm) was observed till the addition of 50 mg/L of EPS, beyond that a blue shift towards 417 nm was observed. The adsorption of EPS was confirmed by Fourier-transform infrared spectroscopy. The EPS adsorbed SNPs were more stable and exhibited the zeta potential of higher than -30 mV.
商业银纳米粒子（SNPs）在水环境中的稳定性对其环境毒性和对人类健康的毒性起着重要作用。在这里，我们研究了细菌胞外多糖（EPS）对工程 SNPs 稳定性的影响。当纳米粒子存在于中性水中时，纳米粒子表现出低的zeta 电位，因此最不稳定。然而，在 EPS（10-250mg/L）存在的情况下，纳米粒子的负表面电荷增加，因此纳米粒子聚集的倾向降低。在紫外-可见光谱分析中，观察到 SNPs（425nm）的等离子体峰的吸光度降低，直到加入 50mg/L 的 EPS，超过该浓度后观察到向 417nm 的蓝移。通过傅里叶变换红外光谱证实了 EPS 的吸附。吸附 EPS 的 SNPs 更稳定，zeta 电位高于-30mV。
