United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu 183-8509, Japan.
Sensors (Basel). 2011;11(11):10063-73. doi: 10.3390/s111110063. Epub 2011 Oct 25.
The presence of toxic metals in drinking water has hazardous effects on human health. This study was conducted to develop GFP-based-metal-binding biosensors for on-site assay of toxic metal ions. GFP-tagged ArsR and CadC proteins bound to a cis element, and lost the capability of binding to it in their As- and Cd-binding conformational states, respectively. Water samples containing toxic metals were incubated on a complex of GFP-tagged ArsR or CadC and cis element which was immobilized on a solid surface. Metal concentrations were quantified with fluorescence intensity of the metal-binding states released from the cis element. Fluorescence intensity obtained with the assay significantly increased with increasing concentrations of toxic metals. Detection limits of 1 μg/L for Cd(II) and 5 μg/L for As(III) in purified water and 10 µg/L for Cd(II) and As(III) in tap water and bottled mineral water were achieved by measurement with a battery-powered portable fluorometer after 15-min and 30-min incubation, respectively. A complex of freeze dried GFP-tagged ArsR or CadC binding to cis element was stable at 4 °C and responded to 5 μg/L As(III) or Cd(II). The solid phase biosensors are sensitive, less time-consuming, portable, and could offer a protocol for on-site evaluation of the toxic metals in drinking water.
饮用水中有毒金属的存在对人类健康有危害。本研究旨在开发基于 GFP 的金属结合生物传感器，用于现场测定有毒金属离子。GFP 标记的 ArsR 和 CadC 蛋白与顺式元件结合，并分别在砷和镉结合构象状态下失去与顺式元件结合的能力。含有有毒金属的水样与固定在固体表面上的 GFP 标记的 ArsR 或 CadC 和顺式元件的复合物孵育。从顺式元件释放的金属结合状态的荧光强度来定量金属浓度。随着有毒金属浓度的增加，测定得到的荧光强度显著增加。在纯化水中，Cd(II)的检测限为 1 μg/L，As(III)的检测限为 5 μg/L，在自来水和瓶装矿泉水，Cd(II)和 As(III)的检测限分别为 10 μg/L，使用便携式电池供电荧光计在 15 分钟和 30 分钟孵育后进行测量，可实现。冻干的 GFP 标记的 ArsR 或 CadC 与顺式元件的复合物在 4°C 下稳定，并对 5 μg/L 的 As(III)或 Cd(II)有响应。固态生物传感器具有灵敏度高、耗时短、便携等优点，可以为现场评估饮用水中的有毒金属提供一种方案。
