Impedance-based assay for pan-cancer early and rapid detection of cell-free DNA

Aberrant DNA methylation is a hallmark of cancer, and plasma cell-free DNA (cfDNA) containing these abnormal methylation patterns has emerged as a promising non-invasive biomarker for pan-cancer detection. However, intrinsic challenges remain that continue to limit its broad clinical application. Here we show a simple and rapid impedance biosensor called Asima Rev that can detect cancer cfDNA in under 5 min without the need for any molecular labelling, electrode modification, signal amplification, or target enrichment steps. Using 216 clinical samples (50 healthy) from 15 different cancer types (all stages) we show an overall sensitivity and specificity of 96.4% and 94.0%, respectively. Differences in methylation content between cancerous and healthy cfDNA lead to distinct solvation behaviour and electro-physicochemical property that remain consistent across cancer types regardless of the distribution patterns of methyl cytosine. Our test exploits this inherent difference.