Magnetic Graphene Field-Effect Transistor Biosensor for Single-Strand DNA Detection

摘要

Herein, a magnetic graphene field-effect transistor biosensor was prepared through the transfer of a chemical vapor deposition graphene film onto a glass substrate to produce a sensing film and conductive channel. By fixing 1-pyrenebutanoic acid succinimidyl ester onto graphene film as an anchor, a probe aptamer was immobilized on the graphene film in order to capture magnetically labeled complementary single-stranded DNA. Our experiments showed that, within a periodic magnetic field, the biosensor impedance exhibited a periodic oscillation, the amplitude of which was correlated to the complementary DNA concentration. Based on this principle, the magnetic graphene field-effect transistor was utilized to detect single-stranded DNA?with detection?limition of 1 pM. The results were rationalized using a model wherein the magnetic force causes the DNA strand to bend, thereby resulting in magnetic nanobeads/DNA modulation of the double conductive layer of graphene transistors. Furthermore,?since a periodic magnetic field could be introduced?to produce a periodic impedance changes of MGFETs,?sampling integration could be used to improve the?signal-to-noise ratio efficiently?by increasing the number of periods of the external magnetic field. Therefore,?a novel biosensor for DNA detection?with high sensitivity has been presented in this work. Based on the detection principle,?this system may also be a potential tool for detecting other bio-molecules, cells, etc.