'Plug and play' microelectrode assisted with Y-motif-mediated primer-free cyclic signal amplification for sensitive quantitation of DNA methyltransferase activity

DNA methyltransferase (MTase), modulating the level of genomic DNA methylation, harbors both a pharmacological target for clinical therapy and a potential biomarker for genetic disorders and tumorigenesis. Typical homogeneous electrochemical approaches, employing solution phase probes, have been considered simple, efficient, and economical method, yet these architectures usually require electroactive molecules labeling, rely on weak electrostatic adsorption interaction, and possess low sensitivity. For circumventing the above drawbacks, herein, we devise a 'plug and play' microelectrode featuring microminiaturization, rapid response time and enhanced mass transport to quantify MTase activity through monitoring the variation of diffusion current of methylene blue (MB) induced by the less-mobile G-quadruplex framework. By coupling the unique signaltransduction approach with Y-motif-mediated primer-free cyclic signal amplification (YPCSA), the miniaturized biosensor possesses low detection limit (down to 2.5 x 10-4 U mL-1), high specificity, good stability and satisfying reusability, and has been successfully applied to the screening of MTase inhibitors, holding great potential in clinical diagnosis and pharmacological research.

Automated summary

The study developed a novel microelectrode for detecting DNA methyltransferase activity, which features rapid response time, high sensitivity, and reusability, and can be applied to research on genetic disorders and tumors.