Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene

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• 作者：Chao Zheng ; Le Huang ; Hong Zhang ; Zhongyue Sun ; Zhiyong Zhang ; Guo-Jun Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：7
• 期：31
• 页码：16953-16959
• 全文大小：382K
• ISSN：1944-8252

文摘

Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO₂ substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool.