DETECTION OF ctDNA WITH WATER SOLUBLE TETRAPHENYLENE-BASED FLUORESCENCE PROBE

A water soluble cationic fluorescent probe (TPEDPyMe) was designed and synthesized by attaching two pyridinium moieties onto the tetraphenylethene (TPE) core. The molecular structure of TPEDPyMe was characterized by multiple spectroscopic techniques, and its fluorescence property was examined. As its maternal compound, TPEDPyMe exhibited typical aggregation-induced emission (AIE) behavior, and the emission peaked at around 630 nm in aqueous solution. TPEDPyMe was used as a fluorescent probe to detect ctDNA in tris-HCl buffer solution at a pH value of 7.2. It was found that the fluorescence intensity of the TPEDPyMe in the buffer solution was boosted up to 20 folds when the concentration of ctDNA increased from 0 mu g/mL to 500 mu g/mL. Meanwhile, the emission peaks blue-shifted from 627 nm to 576 nm. In the concentration region from 0 mu g/mL to 50 mu g/mL, the change in fluorescence intensity was linearly proportional to the concentration of ctDNA. In this region, the Stern-Volmer constant or K-SV, was calculated to be 1.4 x 10(2), showing a desirable sensitivity of TPEDPyMe to ctDNA. Moreover, when the concentration of ctDNA increased from 0 mu g/mL to 500 mu g/mL, the emission peak shifted from 633 nm to 578 nm. This phenomenon implies that the TPEDPyMe can be used as a dual-responsive fluorescent label for probing ctDNA, which is of great significance in biosensor technologies. In summary, the present results indicate that TPEDPyMe is a promising fluorescent probe for the detection of DNA species and more detailed investigation is going on in the laboratory.