Semiconducting Polymer Dot-Based Ratiometric Fluorescence Nanoprobe for DNA Detection

A ratiometric fluorescent deoxyribonucleic acid probe was synthesized using the photoinduced electron transfer mechanism, involving the interactions between different fluorescent components and electron acceptors. Double-emission carboxyl functionalized semiconducting polymer dots were synthesized using the nanoprecipitation method and applied as the flurophore, while methylene blue was used as the electron acceptor. Photoinduced electron transfer between different polymer dots components and methylene blue can achieve ratiometric modulation of the overall fluorescence in the system. The addition of deoxyribonucleic acid restores the fluorescence intensity, because the stronger interactions between deoxyribonucleic acid and methylene blue results in methylene blue being separated from the polymer dots. Under the optimized experimental conditions, system fluorescence was restored to its maximum when the concentration of deoxyribonucleic acid reached 200 nM, the linear range was 0.006-200 nM (R2 = 0.995). This probe was reasonably free from interference, showing a good response to deoxyribonucleic acid, with strong application data from actual samples.