Engineering a label- and enzyme-free detection of HIV-DNA on a cyclic DNA self-assembling strategy using G-triplexes as the signal reporter

An efficient amplification strategy based on the G-triplex DNA structure was developed for label- and enzyme-free fluorescence detection of human immunodeficiency virus (HIV) DNA. In this system, three hairpin molecules (H1, H2, and H3) were used to detect the target and amplify the signal. Fluorescence enhancement was achieved by producing more G-triplexes to bind with Thioflavine T. A detection limit of 33 pM with good linearity in the range from 400 pM to 110 nM was observed. This method avoided using of enzyme and cumbersome labeling procedures and was relatively superior to previous G-quadruplex-based approaches, which often encounter some difficulties in control and excitation. Moreover, the application for detecting HIV-DNA in biological fluids indicates that further applications for clinical diagnosis are expected.