Graphene Oxide-Based Biosensor for Food Toxin Detection
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We report results of the studies relating to the fabrication of a highly sensitive label free biosensor based on graphene oxide (GO) platform for the detection of aflatoxin B1 (AFB1) which is most toxic and predominant food toxin, using electrochemical impedance spectroscopy. The structural and optical characterization of GO/Au and anti-AFB1/GO/Au has been done by electron microscopy, Raman, X-ray diffraction (XRD), UV–vis and electrochemical impedance spectroscopy (EIS). The impedimetric sensing response of immunoelectrode as a function of AFB1 concentration reveals wider linear detection range (0.5–5 ng/ml), high sensitivity (639 Ω ng−1 ml), improved detection limit (0.23 ng ml−1) and good stability (5 weeks) for the label-free detection. Association constant (k a) for antigen–antibody interaction obtained as 0.46 ng ml−1 indicates high affinity.
KeywordsGraphene oxide Aflatoxin B1 Immunosensor Electrochemical impedance spectroscopy
We thank the Director, CSIR-National Physical Laboratory, New Delhi, India, for providing the facilities. S.S. acknowledges the financial support from CSIR (SRF: 31/001(0302)/2008-EMRI), New Delhi, India. We thank Dr. V. Reddy and Prof. CheolGi Kim for the XPS measurements. The financial support received from Department of Science and Technology, India (Grant No. DST/TSG/ME/2008/18) and Indian Council of Medical Research, India (Grant No. ICMR/5/3/8/91/GM/2010-RHN) is gratefully acknowledged.
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