Zinquin ethyl ester is a cell membrane-penetrating and selective fluorescent probe for zinc ions that measures intracellular levels of Zn(2+) and Ca(2+) ions and can be used to stain early embryos.

RPE cell uptake of Zn2+ experiment
a. Solution preparation: Use DMSO to prepare a 10 mM Zinquin ethyl ester stock solution. For example, weigh 1 mg of Zinquin ethyl ester and add 0.4825 mL of DMSO.
Note: The prepared stock solution should be stored in aliquots to avoid repeated freezing and thawing. Unused stock solution should be divided into aliquots of single-use volume and stored at -20℃ in the dark.
b. Operation steps:
1. RPE cells were incubated with 0 ~ 18 nM Zn2+ in serum-free MEM without Zn2+ detection level for 60 minutes.
2. After removing extracellular Zn2+ from the culture, the cells were loaded with 2.5 mM zinc fluorescent sensor Zinquin ethyl ester for 30 minutes.
3. Observe the fluorescent Zinquin-Zn2+ complex under a fluorescence microscope with excitation at 364 nm and emission at 385 nm.