Au‐Doped Ag₂Te Quantum Dots with Bright NIR‐IIb Fluorescence for In Situ Monitoring of Angiogenesis and Arteriogenesis in a Hindlimb Ischemic Model

Abstract Fluorescence located in 1500–1700 nm (denoted as the near‐infrared IIb window, NIR‐IIb) has drawn great interest for bioimaging, owing to its ultrahigh tissue penetration depth and spatiotemporal resolution. Therefore, NIR‐IIb fluorescent probes with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. Herein, a novel NIR‐IIb fluorescent probe of Au‐doped Ag₂Te (Au:Ag₂Te) quantum dots (QDs) is developed via a facile cation exchange method. The Au dopant concentration in the Ag₂Te QDs is tunable from 0% to 10% by controlling the ratio of supplied Au precursor to Ag₂Te QDs, resulting in a wide range of PL emission in the NIR‐IIb window and a much‐enhanced PL intensity. After surface modification, the Au:Ag₂Te QDs possess bright NIR‐IIb emission, high colloidal stability and photostability, and decent biocompatibility. Further, in vivo monitoring of the process of angiogenesis and arteriogenesis in an ischemic hindlimb is successfully performed.