Photoactive Hybrid AuNR‐Pt@Ag2S Core–Satellite Nanostructures for Near‐Infrared Quantitive Cell Imaging

The quantitative detection of microRNA (miR) and multimode‐imaging‐induced photothermal therapy in vivo have become the focus of much attention. Platinum (Pt) decorated gold nanorods (AuNR‐Pt) and Ag₂S core–satellite (AuNR‐Pt@Ag₂S) multifunctional nanostructures are fabricated to quantify intracellular miRs (miR‐21), near‐infrared fluorescence cell quantitative imaging, and tumor ablation in vivo. When combined with miR‐21, the nanoassembly displays significant fluorescence intensity in the second window of the near‐infrared region (1000–1700 nm) after 808 nm excitation. The Ag₂S fluorescence intensity has a good linear relationship with the amount of intracellular miR in the range of 0.054–20.45 amol ng_RNA ^?1 and a limit of detection of 0.0082 amol ng_RNA ^?1. The nanoassembly is also used to develop multimodal bioimaging, including near‐infrared, X‐ray computed tomographic, and photoacoustic imaging in HeLa‐tumor‐bearing mice. Moreover, the tumors are completely eliminated by the high photothermal capacity of the AuNR‐Pt@Ag₂S assembly. This nanoassembly provides a multifunctional nanoplatform for the ultrasensitive detection of miRs and tumor diagnosis and therapy in vivo.