Synthesis of a triphenylamine BODIPY photosensitizer with D–A configuration and its application in intracellular simulated photodynamic therapy

Abstract

In this paper, a D–A type triphenylamine BODIPY photosensitizer (MA-BOP) was synthesized. The maximum absorption wavelength of MA-BOP was 502 nm and its molar extinction coefficient was 6.18 × 10⁴ M⁻¹ cm⁻¹. The maximum emission wavelengths of MA-BOP were at 513 nm and 625 nm, which result from the local excited (LE) state and the charge transfer (CT) excited state of the D–A type BODIPY structure, respectively. The generation of the excited state boosted the intersystem crossing, thereby promoting the conversion from oxygen to singlet oxygen during the triplet relaxation. The singlet oxygen yield of MA-BOP was measured as 20.12%. Meanwhile, the cell viability experiments demonstrated that MA-BOP in the concentration range of 2–12 μM had low cell cytotoxicity and the phototoxicity cell experiment also showed that MA-BOP can eliminate more than 50% of cancer cells under irradiation in 10 minutes at a concentration of 12 μM. Furthermore, the intracellular photodynamic therapy experiment showed that MA-BOP can produce singlet oxygen and kill cancer cells under the irradiation of monochromatic light. This series of experiments indicated that MA-BOP could be considered as a promising photosensitizer for future PDT applications.