Enhanced cytotoxic activity of curcumin on cancer cell lines by incorporating into gold/chitosan nanogels

The present research reports the successful synthesis of curcumin loaded core-shell nanostructures composed of gold nanoparticles and chitosan. Gold nanoparticles were obtained by reducing AuCl4- in the presence of tripolyphosphate (TPP) and chitosan. The prepared gold/chitosan (gold/CS) nanogels were characterized by UV-Vis spectroscopy. The particle size of the gold/CS core-shell nanogels was determined by DLS to be 36.85 +/- 3.21 nm and the XRD analysis confirmed the crystal structure of gold. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) both confirmed the formation of spherical nanoparticles with the average particle size of about 35 nm. The results revealed drug loading and encapsulating efficiency for curcumin to be 11 +/- 3.55% and 78.66 +/- 3.05%, respectively. The drug release profile of nanocarrier was studied both in acidic and neutral buffered solutions (pH values of 5.3 and 7.4) and the results showed that the nanocarrier responded dramatically to acidic pH. Fluorescent images proved the successful internalization of the gold/CS nanostructures into Huh7 and MCF7 cells. The data from cell viability assays also demonstrated much better cytotoxic effects of the curcumin-loaded nanogels compared to free curcumin on both MCF7 and Huh7 cell lines. According to our findings, the gold/CS nanostructures can be presented to further investigations in order to find out new solutions to improve therapeutic efficiency of curcumin.