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-HCI 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 μg/mL to 500μg/mL. Meanwhile,the emission peaks blue-shifted from 627 nm to 576 nm. In the concentration region from 0 μg/mL to 50 μg/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 × 10, showing a desirable sensitivity of TPEDPyMe to ctDNA. Moreover, when the concentration of ctDNA increased from 0 μg/mL to 500 μg/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.