A novel fluorescence method for highly sensitive detection of T4 polynucleotide kinase based on the polydopamine nanotubes
Herein, a novel fluorescent method for detection of T4 polynucleotide kinase (T4 PNK) based on the FRET between dye labeled DNA and polydopamine nanotubes (PDANTs). PDANTs can bind and quench fluorescent dye-labeled single-stranded DNA (ssDNA) probes, while it has less affinity toward double-stranded DNA (dsDNA). With the T4 PNK and ATP, λ exonuclease initiated the hydrolysis of the 5-phosphoryl termini of dsDNA and release ssDNA, which can be strongly adsorbed on PDANTs and the fluorescence intensity decreased. On basis of this, we have successfully established a proposed method for detecting T4 PNK. The method displayed a detection limit of 0.01 U mL-1 with a linear range from 0.01 to 50 U mL-1. In addition, we investigate the effect of several inhibitors including (NH4)2SO4 and NaCl. The method provides a platform for T4 PNK detection and evaluate inhibitors.