A pH-Induced Reversible Assembly System with Resveratrol-Controllable Loading and Release for Enhanced Tumor-Targeting Chemotherapy.

In this report, we present a pH-induced reversible assembly system (PIRAS) based on ferritin (Ft) for targeted tumor therapy. It has been developed to easily load and release of the anticancer drug resveratrol (RV), based on its natural pH-sensitivity and unique hollow cavity of Ft. A tumor-specific target peptide Arg-Gly-Asp (RGD) was conjugated onto the surface of RV-loaded Ft (RV@Ft), to form biocompatible nanoparticles (RV@Ft-RGD). The pH-sensitivity of Ft allows it to be denatured into a hollow porous nanosphere under acidic condition and renatured into a sealed hollow nanosphere under neutral condition. Using pH manipulation, RV@Ft-RGD, with a ~ 21 nm diameter, showed a high RV loading ratio of 79.6%. pH-triggered RV release was then measured at a ratio of 50.3% at pH5.0 over 24 h. Under neutral condition, the RV@Ft-RGD showed excellent stability over 20 days. Confocal fluorescence imaging showed that RV@Ft-RGD had a high cell uptake ratio and co-localization with the lysosome, mainly due to the RGD-mediated target effect. Based on the high drug loading, pH-triggered release, and tumor cell targeting effect, RV@Ft-RGD showed great cell-killing ability in vitro and in vivo. The biocompatibility in vitro and in vivo was also demonstrated to be excellent, without systematic toxicity. The design concept of PIRAS based on Ft significantly inhibits tumor growth and simultaneously further broadens the application of Ft in nanomedicine.