Long-wavelength absorbing and mitochondria or lysosome organelle-targeting photosensitizers with flexible or rigid terminus for fluorescence imaging and high-performance photodynamic therapy

Abstract

In this study, two chlorin photosensitizers (PSs) having long-wavelength absorbing (λmax 707 and 709 nm) and mitochondria or lysosome organelle-targeting abilities have been developed for use in photodynamic therapy (PDT). We simply modified two PSs, PS1 (N-propyl unit as a flexible terminus) and PS2 (N-propargyl unit as a rigid terminus), which displayed near-infrared absorption and fluorescence emission and high 1O2 quantum yield (0.720 and 0.593), indicating a suitable PS for PDT, resulting in high-performance photodynamic activity with low IC50 values (0.31–0.36 μM against A549 and HeLa cells). Importantly, PS1 and PS2 exhibited excellent mitochondrial or lysosomal organelle-targeting ability with high Pearson's correlation coefficient values (∼0.9). The excellent PDT effect of PS1 and PS2 was confirmed by fluorescence images of intracellular reactive oxygen species generation as well as live/dead staining images. Therefore, these two PSs have great potential as fluorescence imaging materials and PDT reagents.