Templated-assisted one-dimensional silica nanotubes: synthesis and applications

Silica (SiO(2)) is one of the most frequently used inorganic materials. This review covers the research progress in the synthesis of one-dimensional silica nanotubes as well as the newest aspects of silica nanotubes in applications where their structural attributes are exploited. The synthetic methods for well-defined silica nanotubes and a variety of specific silica nanotubes including hollow silica nanotubes, mesoporous silica nanotubes, chiral or helical silica nanotubes are summarized. One-dimensional tubular silica nanomaterials display structures that differ from those of other kinds of nanostructured silica materials and provide unique features such as very uniform diameter, open at both ends. In addition, sol-gel process and silane chemistry offer the reliable and robust surface modification or functionalization of silica nanotubes. Attractively, end functionalization of silica nanotubes may be able to control drug release, resulting in their wide applications in controlled drug and gene delivery; also their distinctive inner and outer surfaces can be differentially functionalized making silica nanotubes ideal multifunctional nanostructure candidates for biomedical applications in various areas such as biosensing, bioseparation and biocatalysis.