Bifunctional complexes based on photosensitizers and chrysin enhance the anti-tumor effects of photodynamic therapy

Abstract

The conjugate and nano drugs based on PPA and chrysin are designed and prepared for photodynamic therapy in anti-tumor. To compare the photodynamic activity of two different forms of photosensitizers combined with chemotherapeutic drugs against melanoma B16 cells in vitro and tumor enrichment ability in a breast cancer 4T1 tumor-bearing mouse model. Although nanodrugs have the advantage of excellent aqueous dispersion, the disordered, misaligned stacking between PPA and chrysin weakens their tumor-targeting ability. However, compared to the nano-drug PPA@Chrysin, the bifunctional conjugate PPA-Chrysin not only reduces the dark toxicity of photosensitizer but also enhances the PDT treatment effect via the synergistic effect of chemotherapy at a therapeutic concentration of 0.19 µmol/L. In addition, as a new photosensitizer, PPA-Chrysin retains the tumor-targeting enrichment ability of porphyrins and has excellent photophysical properties, including a fluorescence lifetime of 5.80 ns, a fluorescence quantum yield of 41.4 %, and a singlet oxygen yield of 35.6 %.