A Novel Strategy for Visualizing, Tracing, and Measuring the Gastrointestinal Absorption of Silver Nanoparticles

Abstract The silver‐based formulation has become one of the most widely used nanoagents for agrifood industry and clinical translation. However, the in vivo fate of silver nanoparticles (AgNPs) via oral exposure remains poorly understood. Here, a specific strategy is shown for tracking the gastrointestinal transformation, intestinal absorption, and organ distribution of particulate Ag after oral exposure by using the gold (Au)‐Ag core−shell NPs (Au@AgNPs). Taking advantage of both plasmonic and elemental characteristics of Au@AgNPs, the transformation of particulate Ag in the gastrointestinal tract (GIT), and later on, intestinal absorption are visualized at the single‐particle level. Furthermore, quantitative analysis reveals that the clearance rate of ingested particulate Ag from the blood and organs is much higher than that of ionic Ag, and at 6 h post‐oral administration, the former only contributed 0.08%, 1.10%, and 0.64% of the total Ag in the liver, spleen, and kidneys. Finally, the transcellular and paracellular pathways are identified as two possible mechanisms responsible for the transepithelial transport of particulate Ag. This study opens an avenue toward the examination of oral bioavailability of NPs and may have important implications in exploring the oral delivery technologies of nanoagents.