A micelle formable from at least one nanotube in a process of self-assembly, the nanotube comprising an amphophilic nanotube (2, 8, 14) made from one or more species selected from the group of carbon, silicon, a noble metal, silicon dioxide and titanium dioxide. A part of the nanotube (2, 8, 14) is functionalised and a surfactant molecule or emulsifying agent is attached to the functionalised part. The nanotube (2, 8, 14) may have magnetic properties. A therapeutic agent may be incorporated in the micelle. The micelle may be coated to form a capsule (24). The capsule (24) can be introduced to the human or animal body for treatment of tumors or targeted drug delivery when a magnetic field or near-IR radiation is applied.
