Nanotechnology offers tremendous potential for future biomedical technology. Due to their unique characteristics including superparamagnetic or fluorescent properties, and small size comparable to biomolecules, nanostructured materials have emerged as novel bioimaging, diagnostic, and therapeutic agents for the future medical field. Especially, the combinations of various nanostructured materials with different properties can offer synergetic multifunctional nanomedical platforms, which make it possible to accomplish multimodal imaging, and simultaneous diagnosis and therapy. Moreover, the conjugation of targeting moieties on the surface of these multifunctional nanomaterials gives them specific targeted imaging and therapeutic properties. In this tutorial review, we will summarize the recent reports on the fabrication strategies of multifunctional nanoplatforms and their applications to targeted multimodal imaging and simultaneous diagnosis and therapy.

Porous biomaterials have been widely used as scaffolds in tissue engineering and cell-based therapies. The release of biological agents from conventional porous scaffolds is typically governed by molecular diffusion, material degradation, and cell migration, which do not allow for dynamic external regulation. We present a new active porous scaffold that can be remotely controlled by a magnetic field to deliver various biological agents on demand. The active porous scaffold, in the form of a macroporous ferrogel, gives a large deformation and volume change of over 70% under a moderate magnetic field. The deformation and volume variation allows a new mechanism to trigger and enhance the release of various drugs including mitoxantrone, plasmid DNA, and a chemokine from the scaffold. The porous scaffold can also act as a depot of various cells, whose release can be controlled by external magnetic fields.