The Orthogonal α-meso-Linked bisBODIPY Photosensitizers Demonstrate Effective Two-Photon Fluorescence Imaging and Photodynamic Therapy

Hypoxic tumor microenvironments pose significant challenges to the clinical translation of cancer photodynamic therapy (PDT). While heavy atom-free Type-I boron dipyrromethenes (BODIPYs) photosensitizers can alleviate this challenge by reducing oxygen dependency, but they remain scarce. Herein, heavy-atom-free alpha,meso-linked bisBODIPYs were designed and synthesized. These bisBODIPYs exhibit remarkable red-shifted emission (lambda emmax similar to 670 nm), large Stokes shifts (similar to 4480 cm(-1)) and they are capable of producing both superoxide anion (O-2(center dot-)) and singlet oxygen (O-1(2)) in solution and cells. Additionally, they offer a wide PDT treatment window, ranging from 0.26 to 83.5 mu M. Furthermore, these bisBODIPYs also demonstrate superior two-photon fluorescence, promising for surgical navigation and integrating diagnosis with treatment.