A novel DNA methylation biosensor by combination of isothermal amplification and lateral flow device

The aberration in DNA methylation pattern has been proved as a promising biomarker for early cancer diagnosis, prognosis and therapy from clinical perspective. In the era of precision medicine, current technologies for DNA methylation identification require not only professional and time-consuming operation but also sophisticated apparatus and complex data interpretation, which has highlighted the need to develop a straightforward and competent strategy for DNA methylation detection. Therefore, the present research is dedicated to establish a novel biosensor by integrating of loop-mediated isothermal amplification (LAMP) and lateral flow device (LFD) to identify trace of DNA methylation from highly heterogeneous cancerous specimen. In order to resolve the natural contradiction between sensitivity and specificity in nucleic acid amplification-based detection methods, we introduce the biotin labeled inner primer and digoxigenin labeled dUTP into LAMP-LFD for the first time, which allow this biosensor to identify as low as 150 copies or 0.1 % target variants under strong interferential background within 35 min after bisulfite conversion. Furthermore, the gold magnetic nanoparticle serving as a signal generator in LFD enables the result to be interpreted through both visual and magnetic detection. The promoter methylation pattern of miR-34a, a significant tumor suppressor gene, has been investigated using LAMP-LFD with cell lines and clinical samples, which indicate that this biosensor may be readily adapted for detection of other DNA methylation biomarkers as a sensitive screening tool for cancer diagnosis.