Metasurface Biosensors Enabling Single-Molecule Sensing of Cell-Free DNA

Inthis study, we have revealed that highly fluorescence (FL)-enhancingall-dielectric metasurface biosensors are capable of detecting single-targetDNA, which is cell-free DNA (cfDNA) specific to the human practiceeffect. The ultimately high-precision detection was achieved in ascheme combining the metasurface biosensors with a short-time nucleicacid amplification technique, that is, a reduced-cycle polymerasechain reaction (PCR). In this combined scheme, we obtained a seriesof FL signals at a single-molecule concentration, reflecting the Poissondistribution, and moreover elucidated that the FL signals exhibitthe single-molecule cfDNA detection with more than 84% statisticalconfidence in an automated FL detection system and with 99.9% statisticalconfidence in confocal FL microscopy. As a result, we have found asimple and practical test to discriminate the target of 1 copy/testfrom zero using metasurface biosensors, which has not been realizedby other elaborate techniques such as digital PCR.

Automated summary

This study demonstrates that highly fluorescence-enhancing all-dielectric metasurface biosensors can detect single-target cell-free DNA (cfDNA) specific to human practice effect. By combining metasurface biosensors with a reduced-cycle polymerase chain reaction (PCR) technique, high-precision detection of cfDNA was achieved. The results showed that the metasurface biosensors can successfully discriminate the target from zero at a single-molecule concentration with high statistical confidence.