Multifunctional Gold Nanoparticle-Based Fluorescence Resonance Energy-Transfer Probe for Target Drug Delivery and Cell Fluorescence Imaging.

Drug delivery system has a profound significance for imaging capabilities and monitoring apoptosis process precisely in cancer therapeutic field. Herein, we designed cysteamine (CS)-stabilized gold nanoparticles, CS-gold nanoparticles (AuNPs)-doxorubicin (DOX), for fluorescence-enhanced cell imaging and target drug delivery. For cancer therapy, DOX was incorporated to CS-AuNPs by disulfide linkages which could be cleaved by glutathione (GSH) in cancer cells specifically. In addition, red-emissive DOX was quenched effectively by particular quenching effect of fluorescence resonance energy transfer from DOX to AuNPs, rendering monitoring target drug release by visual luminescence. The released DOX-SH acted as an indicator for cancer cells with red fluorescence and was further used for stimuli-responsive drug therapy. After an overall investigation of detection for GSH, proapoptosis for cancer cells, and inhibition for tumor tissues in vivo, the CS-AuNPs-DOX nanoprobe shows an obviously enhanced performance. This proposal provides an intelligent strategy for cell imaging and drug delivery, which serves as a promising candidate for anticancer therapeutic applications.