BODIPY Derivatives for Photodynamic Therapy: Influence of Configuration versus Heavy Atom Effect.

Heavy atom effect and configuration are important for BODIPY derivatives to generate singlet oxygen (1O2) for photodynamic therapy. Herein, a series of BODIPY derivatives with different halogens were synthesized. 1O2 quantum yields (QYs) and MTT assay confirm that incorporation of more heavy atoms onto dimeric BODIPY cannot effectively enhance the 1O2 QYs. Rather, the dark toxicity increases. This phenomenon can be attributed to the competition of heavy atom effect and configuration of dimeric BODIPY. In addition the BODIPY derivative with two iodine atoms (BDPI) owns the highest 1O2 QYs (73%) and the lowest phototoxicity IC50 (1 μM). Furthermore, an in vivo study demonstrates that BDPI NPs can effectively inhibit tumor growth and can be used as a promising threanostic agent for photodynamic therapy in clinic.