Transcytosis‐Based Renal Tubular Reabsorption of Luminescent Gold Nanoparticles for Enhanced Tumor Imaging

Abstract Transcytosis‐based tubular reabsorption of endogenous proteins is a well‐known energy‐saving pathway that prevents nutrient loss. However, utilization of this well‐known reabsorption pathway for the delivery of exogenous nanodrugs remains a challenge. In this study, using the surface mimic strategy of a specific PEPT1/2‐targeted Gly−Sar peptide as a ligand, renal‐clearable luminescent gold nanoparticles (P−AuNPs) were developed as protein mimics to investigate the transcytosis‐based tubular reabsorption of exogenous substances. By regulating the influential factors (H + content in tubular lumens and PEPT1/2 transporter counts in tubular cells) of Gly−Sar‐mediated transcytosis, the specific and efficient interaction between P−AuNPs and renal tubular cells was demonstrated both in vitro and in vivo. Efficient transcellular transportation significantly guided the reabsorption of P−AuNPs back into the bloodstream, which enhanced the blood concentration and bioavailability of nanoparticles, contributing to high‐contrast tumor imaging.