Redox responsive curcumin-loaded human serum albumin nanoparticles: Preparation, characterization and in vitro evaluation

The purpose of this study was to fabricate redox-responsive human serum albumin (HSA) nanoparticles (NPs) through self-assembly of HSA molecules for incorporation of curcumin (CCM) as a hydrophobic drug molecule. The structural changes of HSA in self-assembly process of nanoparticle formation were investigated using fluorescence, UV-vis, circular dichroism spectroscopy and X-ray diffraction. Spectroscopy data show changes in secondary and tertiary structures of HSA in the process of nanoparticle formation, which can be indicative of the interaction of the hydrophobic drug with HSA molecules. Unlike free CCM, nanoparticulate curcumin is readily dispersed in aqueous medium. Furthermore, self-assembled HSA-CCM NPs release CCM in an environment imitating the intracellular environment with the trigger of acidic pH and redox potential. The in vitro release studies showed that at pH 7.4 only 26% CCM was released from CCM-loaded HSA NPs in 48 h. However, the release of CCM was significantly accelerated in the presence of 10 mM glutathione (GSH) at pH 7.4 or pH 5.5, in which 57% and 70% of CCM was released, respectively. The incorporation of CCM in HSA nanoparticles enhanced the cellular uptake of CCM in comparison with free CCM results in higher anticancer efficacy against MCF-7 cells.