Fig. 1. Synthesis of NIR-Ⅱ Au NCs. (a) Schematics of structure and characterization of Au₂₅ clusters^[13]; (b) schematics of structure and transmission electron microscope (TEM) image of Au₂₄Cd₁ clusters^[16]; (c) enhancement of NIR-Ⅱ fluorescence of Au₂₅ clusters by doping with metals^[13]; (d) photothermal treatment of cancer with Au₄₄MBA₂₆ nanoclusters guided by NIR-Ⅱ fluorescence and photoacoustic imaging^[15]

Fig. 2. Surface modification of NIR‑Ⅱ Au NCs. (a) Synthesis process and ultraviolet fluorescent spectrum of CD-Au NC^[21]; (b) Au NCs and hydroxyapatite (HA) bind efficiently in vitro, showing obvious NIR‑Ⅱ fluorescence^[19]; (c) structural diagram of Au-PC, peritumor administration of Au-PC clusters, and draining inguinal lymph node (iLN) showing high brightness NIR‑Ⅱ fluorescence within 3 min^[23]

Fig. 3. Vascular imaging of NIR‑Ⅱ Au NCs. (a) Real-time vascular fluorescence imaging using NIR‑Ⅱ Au NCs treated with membrane chemical reactor (MCR)^[18]; (b) thrombolytic process after high-dose recombinant tissue plasminogen activator (rt-PA) is monitored by intravenous administration of NIR-Ⅱ Au NCs^[30]; (c) dynamic fluorescence imaging of skull brain of stroke mice using IR-Ⅱ Au NCs^[13]

Fig. 4. NIR-Ⅱ Au NCs for tumor targeted fluorescence imaging. (a) Significant fluorescence observed at tumor site after intravenous injection of PEG functionalized gold nanoclusters loaded with photosensitizer Ce6 (Ce6@GNCs-PEG)^[41]; (b) tumor nodules can be observed in mice with bowel cancer after oral administration of RNase-A@Au NCs^[43]; (c) Au NCs@PDA-MB nanoprobes for in vivo gastric acid inhibition imaging of mice^[42]

Fig. 5. NIR-Ⅱ Au NCs used for inflammatory and antimicrobial therapy. (a) NIR-Ⅱ Au NCs nano diagnostic agent for in vivo PA and MRI assessment^[66]; (b) schematic chemical structure of NIR‑Ⅱ Au NCs probe for monitoring acute kidney injury and NIR‑Ⅱ fluorescence intensity of kidney at different time points after intravenous injection^[74]; (c) schematic of antibacterial mechanism of Au NCs^[78]; (d) bovine serum albumin-encapsulated Au NCs (BSA@Au) possessing catalase (CAT)‑like activity and ¹O₂ producing capacity, which can be combined with laser therapy for bacterial infection to realized rapid wound healing^[20]