On a site-specific delivery system based on core–shell structured magnetic particles: Preparation and characterization

Abstract In the present work, core–shell structured submicro particles with light-switch of azobenzene were developed as a site-specific delivery system. The core was composed of magnetic Fe3O4 submicro particles, providing the magnetism-guiding and targeting function, and the outer shell was composed of mesoporous silica structure, providing solid mesoporous channels, large surface area, tunable pore sizes and volumes for cargo molecules. The light switch of azobenzene was covalently grafted onto the backbone of the outer shell. The core–shell structured submicro particles were characterized and identified by SEM, TEM, XRD, IR spectra, N2 adsorption/desorption isotherms, UV–Vis absorption and emission spectra. Experiment data confirmed the successful preparation of core–shell structured submicro particles with light-switch of azobenzene. The magnetic core was as wide as ∼160 nm and the outer shell was found to own mesopores to load cargo molecules. The controllable release character of these submicro particles was also investigated. With the help of light-switch of azobenzene, controllable release of cargo molecules was successfully realized.