Cy3 Cyanine Dye with Strong Fluorescence Enhancement for AGRO100 and Its Derivative

Nucleic acids, as important substances for biological inheritance, have attracted extensive attention in the biomedical field. More and more cyanine dyes are emerging as one of the probe tools for nucleic acid detection due to their excellent photophysical properties. Here, we discovered that the insertion of the AGRO100 sequence can specifically disrupt the twisted intramolecular charge transfer (TICT) mechanism of the trimethine cyanine dye (TCy3), resulting in a clear "turn-on" response. Moreover, the fluorescence enhancement of TCy3 combined with the T-rich AGRO100 derivative is more obvious. One explanation for the interaction between dT (deoxythymidine) and positively charged TCy3 may be that its outer layer carries the most negative charge. This study provides a theoretical basis for the use of TCy3 as a DNA probe, which has promising applications in the DNA detection of biological samples. It also provides the basis for the following construction of probes with specific ability for recognition.