Sensors 2011, 11(11), 10063-10073; doi:10.3390/s111110063
Article

Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex

1email, 2email, 1,2email and 1,2,* email
Received: 16 September 2011; in revised form: 18 October 2011 / Accepted: 24 October 2011 / Published: 25 October 2011
(This article belongs to the Section Biosensors)
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Abstract: 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.
Keywords: biosensor; ArsR; CadC; GFP; metals; cis element; trans factor; lyophilization
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Siddiki, M.S.R.; Kawakami, Y.; Ueda, S.; Maeda, I. Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex. Sensors 2011, 11, 10063-10073.

AMA Style

Siddiki MSR, Kawakami Y, Ueda S, Maeda I. Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex. Sensors. 2011; 11(11):10063-10073.

Chicago/Turabian Style

Siddiki, Mohammad Shohel Rana; Kawakami, Yasunari; Ueda, Shunsaku; Maeda, Isamu. 2011. "Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex." Sensors 11, no. 11: 10063-10073.


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