An NIR triphenylamine grafted BODIPY derivative with high photothermal conversion efficiency and singlet oxygen generation for imaging guided phototherapy

Osteosarcoma, the most common malignant bone tissue tumor, with a high degree of malignancy, strong metastasis, and early lung metastasis, can result in extremely high mortality, and is a serious threat to human health. Boron dipyrromethene (BODIPY) compounds have shown great potential in photodynamic tumor therapy. In this study, an NIR triphenylamine grafted BODIPY derivative (BDPTPA) with high singlet oxygen generation efficiency (35.2%) was designed and synthesized. BDPTPA nanoparticles (NPs) obtained by nanoprecipitation present high photothermal conversion efficiency (52.6%). Both MTT assay and flow cytometry experiments suggest that BDPTPA NPs are able to generate high photo-toxicity and induce apoptosis of osteosarcoma cells, while presenting negligible dark-toxicity towards osteosarcoma cells as well as normal human cells. Cell migration and transwell experiments demonstrate that BDPTPA NPs can inhibit the migration of osteosarcoma cells. Due to the enhanced permeability and retention (EPR) effects, BDPTPA NPs can accumulate in tumor tissue in 6 h. Pharmacokinetic studies in rats indicate that BDPTPA NPs eliminate much more slowly than BDPTPA in 10% DMSO. Under the irradiation of an 808 nm laser, in in vivo experiments, BDPTPA NPs can significantly inhibit tumor growth without side effects towards normal tissues. BDPTPA NPs show good biosafety and excellent therapeutic effect both in vitro and in vivo, indicating their great potential for treatment of osteosarcoma.