Mi Fwu-Long, Wu Shao-Jung, Zhong Wen-Qi, Huang Cheng-Yu
Department of Biochemistry and Molecular Cell Biology, School of Medicine, Taipei Medical University, Taipei 110, Taiwan.
Phys Chem Chem Phys. 2015 Sep 7;17(33):21243-53. doi: 10.1039/c4cp05012f.
A dual-functional sensor based on silver nanoparticles was synthesized by a two-stage procedure consisting of a low-temperature chitosan-Ag(+) complexation followed by a high-temperature reduction of the complex to form chitosan-capped silver nanoparticles (CS-capped Ag NPs). The surface plasmon resonance (SPR) absorption and fluorescence emission of the silver nanoparticles were influenced by the concentration and degradation time of chitosan, and the temperatures of the complexation and reduction reactions. The SPR absorption band was blue-shifted while the intensities of emission and absorption were decreased after reacting the silver nanoparticles with Hg(2+) ions. The silver nanoparticles reacted with Hg(2+) were characterized by high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and surface-enhanced Raman scattering spectroscopy (SERS). The results suggested that the particle growth and aggregation of the silver nanoparticles were caused by the adsorption of Hg(2+) and deposition of Hg(0) on the nanoparticle surface. Direct correlations of the SPR absorption and fluorescence emission with the concentration of Hg(2+) were useful for quantitative analysis of Hg(2+). It was possible to use the dual-functional silver nanoparticles as a colorimetric and fluorescent sensor for sensitive and selective detection of Hg(2+) ions.
通过两步法合成了一种基于银纳米颗粒的双功能传感器，该方法包括低温壳聚糖 - 银离子络合，随后高温还原该络合物以形成壳聚糖包覆的银纳米颗粒（CS包覆的Ag NPs）。壳聚糖的浓度、降解时间以及络合和还原反应的温度会影响银纳米颗粒的表面等离子体共振（SPR）吸收和荧光发射。银纳米颗粒与Hg(2+)离子反应后，SPR吸收带发生蓝移，同时发射和吸收强度降低。通过高分辨率透射电子显微镜（HRTEM）、能量色散光谱（EDS）、X射线光电子能谱（XPS）和表面增强拉曼散射光谱（SERS）对与Hg(2+)反应后的银纳米颗粒进行了表征。结果表明，银纳米颗粒的颗粒生长和聚集是由Hg(2+)的吸附和Hg(0)在纳米颗粒表面的沉积引起的。SPR吸收和荧光发射与Hg(2+)浓度的直接相关性可用于Hg(2+)的定量分析。可以将双功能银纳米颗粒用作比色和荧光传感器，用于灵敏且选择性地检测Hg(2+)离子。
