A carrier-free rigid fluorescent small molecule CF3/S-containing BODIPY probe: Design and synthesis, tumor cell imaging and biological activity evaluation

Excellent photophysical characteristics and structural modifiability characterize BODIPY fluorescent probes. In this study, A carrier-free rigid fluorescent small molecule CF₃/S-containing BODIPY probe (BODIPY-CF₃/S) was designed and synthesized by introducing benzothiophene groups and trifluoromethane groups into the probe structure. By using the benzene ring large conjugate system to modify the parent structure of BODIPY, a rigid conjugate structure with large π-bonds was formed, improving the photophysical characteristics, increasing the fluorescence wavelength, and improving the intensity and stability of the fluorescence emission. The introduction of benzene ring system and trifluoromethane group makes the probe have good fat solubility. Solvent evaporation was used to create single crystals, and the rigid large conjugate structure of the crystals was seen. Following testing, the probe's photophysical characteristics at various pH values held up well and were largely stable. The BODIPY-CF₃/S fluorescent marker exhibits good biocompatibility with both HCT-116 and HeLa tumor cells, and can enter the cell interior without any carrier due to its excellent fat solubility. Its ability to emit a distinct green fluorescent signal makes it useful for follow-up observation and visualization. As such, it has potential applications as a fluorescent marker. In addition, in vitro cytotoxicity studies, the probe showed good inhibition on A549 cancer cells and HCT-116 cancer cells. In summary, the prepared BODIPY-CF₃/S fluorescent probe has the advantages of long wavelength, strong conjugation stability, good photophysical quality, no carrier and strong fat solubility. These attributes will give researchers and designers of BODIPY rigid conjugated fluorescent probes new ideas for their future research and development.