Poloxamer 407 (F127) is a nonionic surfactant that is 100% active and relatively non-toxic to cells at low concentrations, and frequently used with dye AM esters such as Indo-1 AM, Fura-2 AM, Calcein AM, Fluo-3 AM, Fluo-4 AM, Quest Fluo-8 AM and Quest Rhod-4 AM, etc. to improve their water solubility. Poloxamer 407 is also a lipoprotein lipase inhibitor[1][2].