Fabrication of hollow-structured composite microspheres with amphiphilic and superparamagnetic properties

Solvent etching is a general method for the fabrication of hollow-structured nano/micro-spheres with multiple functions. In this study, we report a facile route for the preparation of hollow composite microspheres, which are amphiphilic and superparamagnetic. In a template of magnetic composite microspheres, P(St-AA)/Fe3O4/PAA, P(St-AA) was selectively etched, resulting in a hydrophobic hollow structure with a shell of hydrophilic polymeric brushes. The effects of etching on the morphology, hollow structure, saturation magnetization, amphiphilic property and cytocompatibility were investigated. Characterization showed that the hollow composite microspheres obtained possessed a well-defined spherical structure, a high saturation magnetization, amphiphilic properties and good cytocompatibility, making them promising as a potential biomaterial in magnetic resonance imaging and drug delivery systems.