Target‐Induced Core–Satellite Nanostructure Assembly Strategy for Dual‐Signal‐On Fluorescence Imaging and Raman Quantification of Intracellular MicroRNA Guided Photothermal Therapy

Abstract Integrating biological detection and treatment into one system is a smart therapeutic maneuver for efficient cancer treatment. Herein, a target‐activated core–satellite nanostructure (CS nanostructure) assembly built on gold nanobipyramids motor (AuNBPs motor)/gold nanoparticle probe (AuNP probe) exhibiting simultaneous dual signal‐on imaging, quantification of intracellular microRNA‐21 (miR‐21), and photothermal therapy (PTT) for cancer is designed. Of note, when the AuNBPs motor/AuNP probe enters into cells, miR‐21 triggers the reaction between AuNBPs motor and AuNP probe, resulting in the formation of CS nanostructure assembly. The process of assembling the CS nanostructure is accompanied with strong fluorescent signals from TAMRA and surface‐enhanced Raman scattering (SERS) signals from adenine. The fluorescent signal is leveraged to image the intracellular miR‐21 level, whereas the SERS signal is utilized for absolute quantification of intracellular miR‐21, and the CS nanostructure acts as the photosensitizer for PTT. This strategy can successfully image and quantify miR‐21 in a single cell, and also distinguish normal cells from tumor cells. Moreover, under the guidance of fluorescence signal, the assembly kills tumor cells and inhibits tumor growth via PTT. In vitro and in vivo results prove that the proposed strategy possesses enormous potential for application in the diagnosis and treatment of cancer.