title: A graphene field effect capacitive Immunosensor for sub-femtomolar food toxin detection.
abstract: In this paper we report the sensing of aflatoxin B1(AFB1) by field effect capacitive method using electrophoretically deposited reduced graphene oxide (RGO) films for the first time. The RGO film has been characterized using SEM, surface profilometer and Raman spectroscopy. It has been observed that both quantum capacitance of RGO (Cq) and effective electrical double layer capacitance (C(EDL)) contribute significantly towards the overall sensitivity for molar concentration in the range of 20-50 mM. As Cq and CEDL changes in opposite direction after AFB1 capture and the nature of frequency dependence of Cq and CEDL are different, the sensitivity shows a minima at a particular frequency. Interestingly, the sensitivity minima is also dependent on AFB1 concentration. Further, the maximum sensitivity obtained is around 30% for 10(-4) ppt (0.1 fg/ml) AFB1 which is greater than 1.5 times that of previous reports. This has been possible through the enhanced biomolecule immobilization capability of RGO. Thus the RGO based field effect capacitive sensor provides a combined advantage of both a high sensitivity and concentration dependent frequency behavior.
authors: Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India.
authors: J
authors: J
authors: Basu
authors: Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India.
authors: S
authors: S
authors: Datta
authors: Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India. Electronic address: chirosreepram@yahoo.com.
authors: C
authors: C
authors: RoyChaudhuri
mesh_terms: D016604:Aflatoxin B1 / Q000737:chemistry / Q000302:isolation & purification*; D015374:Biosensing Techniques; D004586:Electrophoresis; D005504:Food Analysis; D006108:Graphite / Q000737:chemistry; D006801:Humans; D010087:Oxides / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: D010087:Oxides; D006108:Graphite; D016604:Aflatoxin B1
keywords: Double layer capacitance; Field effect capacitance; Food toxin detection; Quantum capacitance; Reduced graphene oxide