Graphene based E. coli sensor on flexible acetate sheet

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• 作者：Palash Kumar Basu ; Deepthi Indukuri ; S ; eep Keshavan ; Vikas Navratna ; Siva Rama Krishna Vanjari ; Srinivasan Raghavan ; Navakanta Bhat
• 关键词：Graphene ; Flexible substrate ; E. coli sensor ; Methyl group ; RC model
• 刊名：Sensors and Actuators B: Chemical
• 出版年：January, 2014
• 年：2014
• 卷：190
• 期：Complete
• 页码：342-347
• 全文大小：1517 K

文摘

A low cost, reagent free, Escherichia coli sensor is demonstrated with graphene, on transparent flexible acetate substrate. Graphene is grown on 100 渭m thick Cu foil, using CVD process and subsequently transferred on to a flexible acetate substrate. Gold electrodes are deposited on graphene to form a two terminal, interdigitated capacitor structure. Impedance spectroscopy (10 Hz to 100 kHz) is performed to characterize the change in impedance, as a function of E. coli concentration on graphene surface. The residual methyl groups on graphene, resulting from the transfer process, act as binding sites for E. coli. It has been observed that the resistance of graphene decreases with increasing E. coli concentration. This is due to the increased hole doping induced by negatively charged E. coli. A sensitivity of 60% is achieved for an E. coli concentration of 4.5 脳 10⁷ cfu/ml. An equivalent RC model is proposed to explain the sensing mechanism.