JC-1 (CBIC2) is a fluorescent lipophilic carbocyanine dye. It has been used to measure mitochondrial membrane potential. JC 1 can be used in a probe for measuring mitochondrial membrane potential by flow cytometry.

JC-1 fluorescence is usually excited by the 488nm laser wavelength common in flow cytometers[1]. JC-1 (2.5μM) exposed to murine L1210 lymphoblasts, can be detected the presence of both cytoplasmic JC-1 monomer and mitochondrial J-aggregates in these cells. Fluorescent labeling of mitochondria with either JC-1 (1 μg/mL, 15 min), reveals that are distributed irregularly, resulting in regions of high and low mitochondrial content within astrocytes[2]. JC-1 is avidly accumulated in sensitive K562 cells where it displays both a green cytoplasmic and red mitochondrial fluorescence. JC-1 is poorly accumulated in resistant K562 cells, which displays only a slight green fluorescence[4]. JC-1 has been shown to interact with α-synuclein at the acidic C-terminal region with a Kd of 2.6 μM. JC-1 itself does not accelerate the protein aggregation of α-synuclein in the absence of iron, insted, it decelerates the aggregation process by extending the lag phase approx[3].