Abstract
Up to date, the way in which metal nanoparticles are cleared in vivo has yet to be elucidated well. Herein, we report a novel intestinal goblet cell-mediated in vivo clearance pathway to remove metal nanoparticles. Typical metal nanoparticles such as triangular silver nanoplates, magnetic nanoparticles, gold nanorods, and gold nanoclusters were selected as representative examples. These metal nanoparticles were prepared, characterized, and injected via tail vein into a mice model with common bile duct (CBD) ligation. The feces and urines were collected for 7 days to be followed by the sacrifice of the mice and collection of the intestinal and gastric tissues for further analysis. The results showed that all four selected metal nanoparticles were located inside the goblet cells (GCs) of the whole intestinal tissue and were excreted into the gut lumen through the secretion of intestinal GC. Moreover, triangular silver nanoplates and gold nanorods were located inside the gastric parietal cells (PCs). Importantly, nanoparticles did not cause obvious pathological changes in intestinal tissues. In this study, we confirmed that the blood corpuscles are involved in the GCs secretion pathway. Furthermore, we found that the secretion of nanoparticles from intestinal GCs and PCs is accelerated by diarrhea induced via Chinese herbs. In conclusion, metal nanoparticles such as triangular silver nanoplates, magnetic nanoparticles, gold nanorods, and gold nanoclusters can be cleaned away by intestinal GCs and PCs. This novel pathway of in vivo clearance of metal nanoparticles has a great potential for future applications such as new drug design and development, nanoparticle-based labeling and in vivo tracking, and biosafety evaluation of in vivo nanoparticles.