Generation, Characterization, and Application of Hierarchically Structured Self-Assembly Induced by the Combined Effect of Self-Emulsification and Phase Separation

Hierarchically structured magnetic single-hole hollow spheres (MSHS) have been successfully obtained via a facile self-assembly strategy. This methodology allows the double emulsions generated via the combined effect of self-emulsification and phase separation to provide confinement for directing the self-assembly of magnetic nanoparticles (MNPs). The resulting MSHS fully capitalize on both the multifunctional properties of MNPs and container features of single-hole hollow spheres. Moreover, the magnetic properties showed obvious improvement and can be tuned by modulating the assembled structure. Thus, MSHS can be used as a smart platform with multiple functionalities including image contrast enhancement, selective encapsulation for biomacromolecules, on-demand release, and magnetically guided transport. This strategy is very promising in the design of hierarchically structured assemblies for desired applications in biomedicine and other fields.