Fig. 2. COT-conjugated mitochondrial dyes exhibit minimal phototoxicities in HeLa cells. (A) Chemical structures of PKMR and PKMDR. (B) Absorbance and emission spectra of PKMR and PKMDR in methanol. (C) Phototoxicity of PKMR and MTR CMXRos in HeLa cells (averaged, n = 3), measured by cell survival rate after green light illuminations (531/40 nm, 1.7 W cm⁻²). (D) Phototoxicity of PKMDR and MTDR in HeLa cells (averaged, n = 3), measured by cell survival rate after red light illuminations (628/40 nm, 1.9 W cm⁻²).