Membrane-permeant form of Rhod-2 that can be loaded into cells via incubation. Because of the relatively low water solubility of the AM ester, the mild detergent Pluronic F-127 is often used as a dispersing agent to facilitate dye loading. Rhod-2/AM itself does not bind Ca2 , but it is readily hydrolyzed to Rhod-2 by endogenous esterases once it enters cells.