Label-free and ultrasensitive detection of polynucleotide kinase activity at the single-cell level

Abstract

We develop a simple and label-free fluorescence method for the polynucleotide kinase (PNK) assay based on phosphorylation-triggered isothermal exponential amplification. This method exhibits ultrahigh sensitivity superior to most existing PNK assays. Importantly, this method enables sensitive detection of endogenous PNK activity at the single-cell level, holding great potential in clinical diagnosis and biomedical research.