A mitochondria-targeting NIR fluorescent potassium ion sensor: Real-time investigation of the mitochondrial K+regulation of apoptosisin situ

Abstract

The first NIR fluorescent mitochondria-targeting K+sensor, denoted asTAC-Rh, was developed. The produced sensor consists of a rhodamine analog as the fluorophore and triazacryptand (TAC) as the K+recognition unit. Compared to the K+sensors reported previously,TAC-Rhexhibits two unique optical properties: the largest Stokes shifts (120 nm) and the longest emission peak wavelength (720 nm). With the assistance of this novel sensor, real-time changes of K+concentrations in mitochondria during apoptosis were monitored for the first time. Moreover, it was also the first time that the relationship between mitochondrial K+flux and apoptosis was investigated in real time using fluorescence imaging.