Total solution processable and low-cost DNA methylation sensor

DNA methylation sensor is an emerging demand of modern medical for laboratory, though lots of efforts have been contributed in this discipline, the easy-to-operate and efficient sensing terminal is still in deficiency. In this work, a total solution processable printing technology is proposed to fabricate the DNA methylation sensor, which is based on the liquid gate graphene field effect transistor (Lg-GFET). Meanwhile, the graphene ink (G-ink) was prepared by using the modified liquid-exfoliation method, to facilitate printing production. Then, five kinds of tested single strand DNA (ssDNA) which have 0 to 4 5-methylcytosine (5mC) sites were covalently anchored on the graphene channel. X-ray photoelectron spectroscopy (XPS) was conducted to demonstrate the analyte ssDNA was successfully fixed. Thirdly, the 5mC sites were identified by their antibody of 5mC (5mCab) and transduced as the changed current between the source and drain electrodes (I-ds). It is found the proposed sensor has good linear sensitivity (about -1.68% for per 5mC) to the amount of 5mC sites on the tested ssDNAs with Pearson correlation coefficient -0.98 and excellent anti-interference to unmethylated ssDNAs. Besides, the cost is estimated to be about $ 1.5 for each of the proposed DNA methylation sensor. Conclusively, the proposed low-cost component may be an efficient candidate for promoting the instant DNA methylation determination.