A Rapidly Synthesized, Ultrasmall Silver Nanocluster for Near-Infrared-II Imaging and Metabolic Studies

Near-infrared-II (NIR-II) imaging has emerged as a powerful technique for high-resolution visualization of deep anatomical features, benefiting from minimized autofluorescence, diminished optical scattering, and absorption of tissue. However, the current synthesis of NIR-II nanoprobes is a time-consuming, labor-intensive process with low yields, highlighting the need for an efficient and rapid synthesis approach instead. Herein, we report DNA-templated silver nanoclusters (Ag NCs) with NIR-II emission that can be rapidly synthesized via a simple one-spot process within 2 min. The Ag NCs are about 1.6 nm in size, making it easy for them to enter into the capillaries of muscle tissue. In vivo NIR-II imaging results indicate that the Ag NCs we designed are promising probes for studying the metabolic pathways of nanoprobes after intramuscular injection. Therefore, it is expected that Ag NCs with ultrafast room temperature synthesis, excellent NIR-II emission, and ultrasmall size will be ideal probes for biological applications.