Fig. 4. Real-time and multiwavelength irradiation NIR-IIc imaging demonstrated in vivo.

Real-time vascular luminescence imaging with Tm(02Er)-NPs@PEG in living mice upon 800 nm irradiation (100 mW/cm²) a at NIR-IIc region. b Vascular imaging at 40 min postinjection points with 1500 nm LP and 1700 nm LP filters, respectively. c corresponding luminescence intensity statistics of b. d, Vascular luminescence imaging with Tm- and Er-based NPs at the same concentration in NIR-IIb (1500 nm LP + 1700 nm SP filters, 1500–1700 nm) and NIR-IIc (1700 nm LP filter) subwindow. e corresponding luminescence intensity statistics of e. f Nanoprobe with a mixture of Er- and Tm-based probes at the same intensity in NIR-IIb and NIR-IIc imaging. g corresponding SBR statistics of f. h GI tract imaging in NIR-IIc (1750–2250 nm) region in living mice gavaged with Tm(30Er)-NPs@PEG upon 800 nm, 980 nm, 1208 nm, and 1530 nm irradiation (120 mW/cm² for each), respectively. i Corresponding SBR statistics of h data are presented as mean ± s.d. (n = 4). j The compiled luminescence profiles for the multiple excitations of Tm/Er-NPs. Exposure time: 100 ms.