Magnetic aligned vesicles.

Self-assembled magnetic vesicles based on cationic double-chain dimethyldioctadecylammonium (DODMA(+)) encapsulating two kinds of magnetic polyoxometalates, K(10)[Co(4)(H(2)O)(2)(PW(9)O(34))(2)].20H(2)O ({Co(4)P(2)W(18)}) and Mo(72)(VI)Fe(30)(III)O(252)L(102).180H(2)O with L=H(2)O/CH(3)COO(-)/Mo(2)O(8/9)(n-) ({Mo(72)Fe(30)}), were fabricated in mixed-solvent solution (CHCl(3)+CH(3)OH, 4:1 v/v). The vesicles were characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). SEM and TEM images show that three-dimensional hollow shells of the magnetic vesicles can survive after solvent evaporation. The room-temperature magnetic properties were measured, indicating that {Co(4)P(2)W(18)} and {Mo(72)Fe(30)} retain their magnetic properties after embedding in the vesicles. Interestingly, the self-assembled magnetic vesicles can be aligned under an external magnetic field, which make them ideal candidates as magnetic biosensors for drug-releasing materials. Copyright 2009 Elsevier Inc. All rights reserved.