Systematic investigation of a quantitative paper-based DNA reader (qPDR) for distance-based quantification of nucleic acids and mercury ions

Abstract

Nucleic acid testing using microfluidic paper-based analytical devices (μPAD) offers exciting opportunities for inexpensive, portable diagnostics in resource-limited settings. We have previously developed a portable, affordable, and easy-to-fabricate quantitative paper-based DNA reader (qPDR) capable of quantifying nucleic acids by measuring distance as a digital readout. Here, to decipher specific molecular interactions and identify optimal experimental conditions for using qPDR, we systematically investigated the chromatographic behaviours of SYBR Green I (SG), a key assay component, in the presence of DNA, organic solvents, saline, urea, and surfactants. We also demonstrated the possibility to expand qPDR for the detection of non-nucleic-acid targets. Specifically, we have successfully enabled distance-based quantification of mercury ions with nanomolar detection limit using thymine-rich DNA and qPDR.