Determination of the surface tension of block copolymer micelles by phagocytosis

This work was carried out to determine the surface tension of block copolymer micelles of 14C labelled ABA poly (oxyethylene-bi-isoprene-b-oxyethylene) which have a long circulating half life in animals. The method used was that of phagocytosis. The percentage of micelles phagocytosed by human mononuclear cells was determined in solutions of different surface tension. The values obtained were 72 mN/m which may be predicted for a particle with a long circulating half life in animals. The method also gave an estimate of the surface tension for the mononuclear cells. This technique has the advantage of determining the surface tension of highly hydrated small particles including stable micelles in an environment similar to that in which they normally exist.