Hollow chain-like SiO2/ZnO nanocomposites: Electrospinning synthesis, defect-related luminescence, and applications for drug delivery

A variety of mesoporous SiO2/ZnO hollow nanochains with different molar ratios of Zn/Si have been synthesized by electrospinning followed by a subsequent calcination process. The hollow nanochains consist of long nanotubes that are strung together with nanobeads, and exhibit a typical mesoporous structure, large specific surface area, and high biocompatibility. The SiO2/ZnO nanocomposites show intense defect-related luminescence with blue emission under ultraviolet excitation, which make them possible to monitor and track the drug release process and the fate of the material when used as an inorganic drug carrier. The drug loading reveals that the SiO2/ZnO nanocomposites shows high drug loading efficiency and the release pattern displays a sustained release process after the initial burst. In particular, the SiO2/ZnO hollow nanochains are stable in normal physiological environment and can collapse and decompose in acid buffer solution, which can simultaneously accelerate the drug release process and achieve the pH-responsive drug release pattern. The as-synthesized nanocomposites may act as a promising drug carrier for tumor-targeted therapy due to their well-defined morphology, good biocompatibility, high drug loading capacity, pH-responsive release pattern, eminent biodegradability, and potent anti-cancer effect.