Core-satellite nanostructures and their biomedical applications

Plasmonic core-satellite nanostructures assembled from simple building blocks have attracted extensive attention since they were reported by the way of DNA-directed assembly in 1998, because of their unique enhanced and synergistic optical properties and widespread potential applications in biosensing, imaging, drug delivery, and diagnostics. In this review, we introduce the synthetic methods of core-satellite nanostructures, emphazising the bottom-up synthesis method, including DNA, molecular, protein, peptide, amino acids, metal ion-assisted assembly, electrostatic adsorption assembly, clicked-to-assembly, and in situ deposition. Than we review and discuss their morphology classification, and summarize influencing factors of morphology. This is followed by overviews on optical properties, including localized surface plasmon resonance, surface-enhanced Raman scattering, surface-enhanced fluorescence and quenching, and applications in the biomedical field. Finally, the challenges and prospects of these kinds of nanostructures are discussed.