Template synthesized nanotubes for biomedical delivery applications.

This review details the advances made in alumina template-synthesized nanotubes and nano test tubes as delivery vehicles for biomedical applications. Most current research has focused on spherical nanoparticles because they are easier to make; however, cylindrical particles or nanotubes offer many advantages over spherical particles. One advantage is that the template is tunable, which means the pore diameter and template thickness can be controlled, resulting in larger payload capacities for nanotubes. Another advantage is that template synthesized nanotubes can be differentially functionalized on their inner and outer surfaces. Inner and outer surface nanotube modification for use in drug extraction, antibody-antigen interactions and magnetization is discussed. Recent advances made in covalent capping ('corking') nanotubes to prevent premature payload leakage are also covered. Although many applications for nanotubes have already been discovered, many new and exciting paths await exploration.