Synthesis and characterization of mesoporous Gd₂O₃ nanotube and its use as a drug-carrying vehicle

Gd₂O₃ nanotubes were constructed for the first time by assembling highly crystalline Gd₂O₃ nanoparticles through the use of combined soft template and sol-gel methods. Amphiphilic block copolymer was used as structure-directing agent and gadolinium isopropoxide as inorganic precursor in non-aqueous solution. The amphiphilic copolymer molecules are known to undergo self-organization above a critical micelle concentration, forming micellular architecture that further provides a structurally ordered active site for the nucleation and growth of Gd monomers. The resulting self-assembly of the Gd₂O₃ nanocrystals led to the formation of Gd₂O₃ tubular nanostructure after pyrolytic removal of the template. Transmission electron microscopy analysis indicated a mesoporous channel array along the [110] direction of the nanotubes where the wall of nanotube is well organized by the assembly of a highly crystalline framework of Gd₂O₃ nanocrystals. This Gd₂O ₃ nanotube exhibited weak superparamagnetic property and was found to be able to carry and elute a model molecule, i.e. ibuprofen (IBU), in a controllable manner via an external magnetic field. The mechanism of IBU release from the nanotubes with and without the use of magnetic stimulus was proposed.