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

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.