A disposable DNA methylation sensor based on the printable graphene field effect transistor

The detection of DNA methylation is necessary for the research of epigenetics. In this work we would like to propose a disposable DNA methylation sensor by using graphene field effect transistor (GFET) as the sensing platform. In this component, the liquid-phase exfoliated graphene (LEG) nanosheets were drop-coated on the flexible substrates of polyethylene terephthalate (PET) films. Then, the interdigital structured electrodes (named as source and drain) were printed on the LEG coated PET films to form the expected GFETs. Thirdly, the carbon dots (CDs) decoration was conducted and examined on the asprepared GFETs to evaluate the influence of CDs, as well as optimize CDs’ concentration. At last, the immune identification-based sensing strategy was utilized on the CDs modified GFETs to develop the concerned DNA methylation sensor. The experimental data indicate the proposed sensors could be a potential experimental tool for epigenetic research.

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DNA hydrogel to improve solution-gate graphene field effect transistor in all-solid-state

Journal of Instrumentation ◽

10.1088/1748-0221/16/12/p12034 ◽

2021 ◽

Vol 16 (12) ◽

pp. P12034

Author(s):

S. Hu ◽

Y. Jia

Keyword(s):

Solid State ◽

Field Effect ◽

Field Effect Transistor ◽

Gate Dielectric ◽

Gate Dielectrics ◽

Hydrogel Scaffold ◽

Sensing Platform ◽

Graphene Field Effect Transistor ◽

Effect Transistor ◽

Dna Hydrogel

Abstract The solution-gate graphene field effect transistor (Sg-GFET), as a popular sensing platform, its applications are still hindered by the deficiency in all-solid-state, due to the dependence on liquid-state gate-dielectric. Inspired by DNA hydrogel which can provide microporous architecture to accommodate the fluidic analyte, moreover, its combination with graphene is believed to foster electron transport in the field of electrochemistry. We are interested to take advantage of DNA hydrogel's solid-state and capability for holding solution, and investigate whether it can replace the traditional solution. So pure DNA hydrogel, their complexes with GO (GO/DNA hydrogel) and RGO (RGO/DNA hydrogel) are studied herein. Their micro-porous 3D morphologies are demonstrated, their influences on the electrical characteristics of GFETs are carefully examined and proved to be able to maintain the typical bipolarity of Sg-GFET, firstly. Then, pure DNA hydrogel and GO/DNA hydrogel are selected as the optimized gate-dielectrics, because of their renewability after dehydration. Furthermore, by using aptamer-based heavy metal ions (Pb2+ and Hg2+) detections as proof-of-concept, the strategies for building the sensing platform based on the optimized hydrogel dielectric-gated GFETs are studied. It is found, for the purpose of substituting fluidic dielectric in traditional Sg-GFET, the scheme of directly mounting aptamer on graphene channel and coating pure DNA hydrogel on it is demonstrated to be better than the strategies of using GO/DNA hydrogel and hybriding aptamer probes in hydrogel scaﬀold. It is explained according to surface charge sensing mechanism. At last, the performances of the sensing platform based on the proposed DNA hydrogel gated GFETs are testified by the detections and selectivity examinations for Pb2+ and Hg2+. Conclusively, pure DNA hydrogel is expected to be a promising candidate in the future all-solid-state Sg-GFET.

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