DLS characterization of AuNC@BSA (a) and AuNC@GSH (c), and their HRTEM images (b, d), respectively. (e) The illustration of experiment procedure of systemic distribution and elimination, the two AuNCs were i.v. injected into wild type (WT) mice and obtained the samples at different time points for measurements. (f, g) The AuNCs in circulation were evaluated by ICP-MS. (h) The FLI of brains at multiple time points. The color scale ranges from 1 × 108 to 6 × 108, and unit is (p/sec/cm2/sr)/(μW/cm2). The AuNCs in brains were semi-quantified by FLI (i, j) and quantified by ICP-MS (k, l). In the whole picture, the AuNC@BSA-associated statistic data showed in red curves, while the orange ones for AuNC@GSH, the same below.