The TBI was performed based on the previously reported procedures with modifications43 (link). Briefly, the benchmark stereotaxic impactor was mounted on a stereotaxic frame at 45° (David Kopf Instruments, Tujunga, CA, USA). Anesthetized mice were placed on a customized foam mold in prone position. To induce TBI, the tip was driven towards mouse head at a speed of 4.0–4.5 mm/s, a dwell time of 0.2 s set by the electronic control box and an impact depth of 3 mm adjusted by the stereotaxic device. After 2 h recovery, 4–6-week-old C57BL/6 was intravenously injected with 200 μL anti-CD11b-PEGylated PbS/CdS CSQD (O.D. = 0.5 at 808 nm) and monitored by wide-field system and oblique NIR-II LSM mounted with a 5X illumination objective and a 10X imaging objective 24 h post injection. The Z scanning increment, exposure time and excitation and emission wavelengths were summarized in Supplementary Table 2.