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Toxin Detection by Si Photosensitive Biosensors with a New Measurement Scheme
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- Authors
- Chan Woo Park, Jong-Heon Yang, Chil Seong Ah, Chang-Geun Ahn, Yo Han Choi, Kwang Hyo Chung, Wan-Joong Kim, Gun Yong Sung
- Issue Date
- 2011-11
- Citation
- Biosensors and Bioelectronics, v.29, no.1, pp.219-223
- ISSN
- 0956-5663
- Publisher
- Elsevier
- Language
- English
- Type
- Journal Article
- Abstract
- We propose a new type of photosensitive biosensor with a CMOS compatible Si photodiode integrated circuit, for the high-sensitive detection of small mycotoxin molecules requiring competitive assay approach. In this work, a photodiode is connected to the gate of a field effect transistor (FET) so that the open circuit voltage (V OC) of the illuminated photodiode is transferred into the drain/source current (I DS) of the FET. The sensing scheme employs competitive binding of toxin molecules (within the sample solution) and toxin-BSA conjugates (immobilized on the photodiode surface) with Au-nanoparticle-labeled antibodies, followed by silver enhancement to generate opaque structures on the photodiode surface. By utilizing the non-linear dependence of the V OC on the light intensity, we can maintain a sufficiently high signal resolution at low toxin concentrations (with most of the incident light blocked) for the competitive assay. By monitoring the I DS of the FET whose gate is driven by the V OC, quantitative detection of Aflatoxin B1 has been achieved in the range of 0-15ppb. © 2011 Elsevier B.V.
- KSP Keywords
- Aflatoxin B1, CMOS-compatible, Competitive assay, Field Effect Transistor(FET), High sensitive, High signal, Light intensity, Non-linear dependence, Open circuit voltage(OCV), Photosensitive biosensor, Quantitative detection