Abstract: A composition for facilitating delivery of biological agents, comprising a supramolecular complex including as constituents a block copolymer, having at least one nonionic, water soluble segment and at least one polyionic segment, and at least one charged surfactant having hydrophobic groups, the charge of the surfactant being opposite to that of the polyionic segment of the block copolymer. The constituents of the complex are bound by interaction between the opposite charges thereof and between surfactant hydrophobic groups. The complex may include an anionic surfactant having a biological activity, in which case the net charge of such anionic surfactant is no more than about 10.