Mitochondria play essential roles in cellular energy supply and produce 90% of reactive oxygen species. A mitochondrial targeted photosensitizer is greatly beneficial to improve the photodynamic therapeutic effect via apoptosis. Herein bromo-pentamethine dyes (λ_abs > 650 nm) are designed as mitochondria-localized anticancer photosensitizers. Cell experiments demonstrate that Cy-Br localizes in mitochondria with very low cytotoxicity in dark, and induces cancer cells apoptosis under light with IC₅₀ as low as 62 nM, much better than commercial Ce6 (3706 nM). Bromo-group could enhance the quantum yield of reactive oxygen species. The high efficiency might provide a new clue to develop new photosensitizers.

线粒体在细胞能量供应中起着至关重要的作用，并产生90％的活性氧。线粒体靶向光敏剂对通过细胞凋亡改善光动力治疗效果非常有利。本文溴五甲染料（λ _ABS  > 650纳米）被设计为线粒体定位的抗癌光敏剂。细胞实验表明，Cy-Br在黑暗中定位于线粒体中，具有极低的细胞毒性，并且在光照下诱导癌细胞凋亡，其IC ₅₀低至62 nM，远优于商品Ce6（3706 nM）。溴基可以提高活性氧的量子产率。高效率可能为开发新的光敏剂提供新的线索。