A pH-Responsive System Based on Fluorescence Enhanced Gold Nanoparticles for Renal Targeting Drug Delivery and Fibrosis Therapy

Background Stimuli-responsive gold nano-assemblies have attracted attention as drug delivery systems in the biomedical field. However, there are challenges achieving targeted delivery and controllable drug release for specific diseases. Materials and Methods In this study, a glutathione (GSH)-modified fluorescent gold nanoparticle termed AuLA-GSH was prepared and a Co2+-induced self-assembly drug delivery platform termed AuLA-GSH-Co was constructed. Both the pH-responsive character and drug loading behavior of AuLA-GSH-Co were studied in vitro. Kidney-targeting capability was investigated in vitro and in vivo. Finally, the anti-fibrosis efficiency of AuLA-GSH-Co in a mouse model of unilateral ureteral obstruction (UUO) was explored. Results AuLA-GSH-Co was sensitive to pH changes and released Co2+ in acidic conditions, allowing it to have controllable drug release abilities. AuLA-GSH-Co was found to improve cellular uptake of Co2+ ions compared to CoCl2 in vitro. AuLA-GSH exhibited specific renal targeting and prolonged renal retention time with low non-specific accumulation in vivo. Moreover, the anti-fibrosis efficiency of AuLA-GSH-Co was higher compared to CoCl2 in a mouse model of unilateral ureteral obstruction (UUO). Conclusion AuLA-GSH-Co could greatly enhance drug delivery efficiency with renal targeting capability and obviously relieve renal fibrosis, providing a promising strategy for renal fibrosis therapy.