Abstract
Invisible mercury ion is an extremely poisonous environmental pollutant, therefore, a fast and highly sensitive detection method is of significant importance. In this study, a liquid-gated graphene field-effect transistor (GFET) array biosensor (6 × 6 GFETs on the chip) was fabricated and applied for Hg2+ quantitate detection based on single-stranded DNA (ssDNA) aptamer. The biosensor showed outstanding selectivity to Hg2+ in mixed solutions containing various metal ions. Moreover, the sensing capability of the biosensor was demonstrated by real-time responses and showed a fairly low detection limit of 40 pM, a wide detection ranged from 100 pM to 100 nM and rapid response time below one second. These results suggest that the GFET array biosensor based on ssDNA aptamer offers a simple fabrication procedure and quite fast method for mercury ion contaminant detection and are promising for various analytical applications.
Highlights
Graphene is a two-dimensional and one-atom thick sheet of sp2 hybridized carbon with exceptional electrical and physical properties, such as large detection area, ultra-high electron mobility, tunable ambipolar field-effect characteristic, and biocompatibility, compared to ones based on conventional semiconductor materials
Characterization of Graphene on the graphene field-effect transistor (GFET) According to the methods for graphene fabrication described in part 2.2 of this study, graphene film was synthesized by chemical vapor deposition (CVD) on copper foils and patterned with proper shape after being transferred onto Si/SiO2 substrates
The properties of graphene on the surface of GFET array were explored by Raman spectra analysis
Summary
Graphene is a two-dimensional and one-atom thick sheet of sp hybridized carbon with exceptional electrical and physical properties, such as large detection area, ultra-high electron mobility, tunable ambipolar field-effect characteristic, and biocompatibility, compared to ones based on conventional semiconductor materials. Graphene field-effect transistor (GFET) have recently attracted much interest in sensing field (Dan et al, 2009; He et al, 2010, 2012; Huang et al, 2010, 2011; Myung et al, 2011; Kim et al, 2015; Han et al, 2017; Li et al, 2017; Kotlowski et al, 2018; Mansouri Majd and Salimi, 2018; Xu et al, 2018) for detection of DNA, protein, ions and so on. The binding event between the aptamers and the targets can occur within the electric double layer in buffer solution, and as a consequence, changes in the charge distribution with proximity to the graphene can be detected (Guo et al, 2005; So et al, 2005). The density of the immobilized DNA on the graphene can be controlled, and a high density of DNA can be prepared
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