Figure 8.

(A) Intramolecular spirolactam of RC-TPP is fluorogenically opened by a proton to release the amide form. (B) RC-TPP (20 μM) fluorescence emission in a buffer with a pH range of 4.5 to 9.0 (λ_ex = 425 nm for coumarin and λ_ex = 585 nm for rhodamine). (C) RC-TPP-loaded Tom20-GFP⁺ HeLa cells were treated without or with CCCP (20 μM). Colocalization of Tom20-GFP (green) and mitochondrial RC-TPP (blue) is shown in cyan. Scale bar = 10 mm. Reproduced with permission from ref (80). Copyright 2017 Royal Society of Chemistry.