Self-Assembly/Disassembly of Nanostructures Confers "Off/On" Signal for Molecular Imaging

Molecular imaging (MI) plays an important role in both clinical diagnosis and laboratorial research. Developing a "smart" strategy with higher sensitivity for more precise imaging is of great significance but remains challenging. If employed for MI, the self-assembly/disassembly of nanostructures carries five characteristic superiorities in its specific response to a physiological environment: lower toxicity, longer circulating time, higher imaging efficiency, higher signal-to-noise ratio, and ease of functionalization. This review focuses on recent approaches involving the self-assembly/disassembly of nanostructures for the MI of biological events by using different modalities (e.g., magnetic resonance imaging, optical imaging, plasmonic and photoacoustic imaging). We envision that by incorporating multiple imaging modes to the monomer/nanostructures for self-assembly/disassembly, researchers should be able to use this "smart" system for more precise MI in the near future.