Fluorescein Bis(methylene)]bis[N-(carboxymethyl)glycine] is an intermediate used in the synthesis of Calcein AM (C125400), which is a hydrophobic non-fluorescent probe that can permeate the plasma membrane and can be hydrolyzed to Calcein (sc-202090), which is an extremely fluorescent and negatively charged molecule. Calcein-AM can be used to stain living cells and in cytoplasmic Schwann cells has been observed to fluoresce bright green. Calcein-AM has been reported to be a neutral substrate for P-glycoprotein (Pgp) and multidrug resistance protein (MRP) and has been used in flow cytometry studies to analyze the function of P-gp and MRP.
