Detection of DNA hybridization by a pyrene-labeled polyelectrolyte prepared by ATRP

A novel pyrene-labeled polyelectrolyte (Py-PDMAEMA+) has been prepared by atom transfer radical polymerization (ATRP) for detection of DNA hybridization. The electrostatic and hydrophobic interactions between Py-PDMAEMA+ and ssDNA (hairpin or linear DNA) kept them forming a complex probe which could be used as a turn-off fluorescent sensor. The fluorescence intensity of the probe decreased upon adding the complementary strand, since the pyrene moiety could be intercalated into the duplex and thus the fluorescence quenching by nucleotide bases was strengthened. The proposed intercalation mode was confirmed by the circular dichroism spectra and the fluorescence quenching study with iodide. This pyrene-labeled polyelectrolyte combined with ssDNA may establish a novel fluorescence sensing system for DNA hybridization.