Label-Free DNA Sequence Detection through FRET from a Fluorescent Polymer with Pyrene Excimer to SG

A label-free complex probe composed of a water-soluble fluorescent pyrene-functionalized polymer, ssDNA, and a nucleic acid stain (SG) is presented here, which can detect DNA sequence via FRET from pyrene excimer to SG. Complementary and one-base mismatched strands at nanomolar concentrations can be distinguished by the examination of the FRET fluorescence intensity of SG. This novel strategy for detecting DNA using the fluorescent pyrene-functionalized polymer not only affords a simple label-free method to detect nucleic acid sequence but also endows the detection with high sensitivity and selectivity, which may find wide applications for optical biosensing

Fluorescence Detection of DNA Hybridization Based on the Aggregation-Induced Emission of a Perylene-Functionalized Polymer

A perylene-functionalized polycation was synthesized by quaternization of poly­(4-vinylpyridine) with bromomethyl-perylene and methyl iodide, which exhibited a unique aggregation-induced emission (AIE) effect. The synthesized polycation and polyanion ssDNA could form a complex probe to detect DNA hybridization. Upon adding noncomplementary ssDNA, the fluorescence of the complex probe increased due to the AIE effect; upon adding complementary ssDNA, the fluorescence intensity changed little due to the combined effects of AIE and duplex-quenching resulting from the intercalation of perylene into the duplex