Two-photon microscopy (TPM) is a fluorescence imaging technique which provides greater tissue penetration, limits the excitation volume, and induces less photobleaching, phototoxicity and photodamage.
Mitochondria play a crucial role in cell metabolic processes such as energy production, cell signaling, Ca2+ regulation, production in reactive oxygen spec ies and triggering of cell death.The mitochondrial function depends on its pH. Mitochondrial pH plays a significant role in driving force for the mitochondrial cation homeostasis, production of ATP and neurotransmission an insulin secretion.
Here, we report two mitochondria-targetable two-photon fluorescent pH sensitive probes (CMP-1 and CMP-2) allowing for a quantitative measurement of mitochondrial pH in living cells and tissues. In the probe architecture, we assimilated the donor OH group at the C-8 position of the benzochromene scaffold which enhance the dipole moment and offer larger intramolecular charge transfer (ICT) process. Benzochromene scaffolds of CMP-1 and CMP-2 are different. CMP-1 is bent-π-shaped and CMP-2 is linear-π-shaped. Because conjugation of CMP-2 is larger than CMP-1, the ICT process in CMP-2 would enhance and the pH monitoring with CMP-2 would be occurred in red region which is ruled out the autofluorescence and helpful for enhanced the spectral separation from cellular absorption in biological trial.
