Fabrication of chitosan hydrochloride and carboxymethyl starch complex nanogels as potential delivery vehicles for curcumin

[Display omitted] •Chitosan hydrochloride-carboxymethyl starch nanogels were successfully prepared.•The spherical shape of nanogels was verified by transmission electron microscopy.•Rheological measurements exhibited that the nanogels behaved as viscoelastic solids.•The nanogels showed high encapsulation efficiency of curcumin. The purpose of this research was to prepare nanogels by covalent cross-linking carboxymethyl starch (CMS) and chitosan hydrochloride (CHC) as novel delivery systems for curcumin. The spherical structure of CHC-CMS nanogels was verified by transmission electron microscopy. Fourier transform infrared spectroscopy confirmed that the amide linkage was formed between CHC and CMS. X-ray diffraction data exhibited that the crystalline structure of CHC was destroyed after covalent cross-linking with CMS, which further confirmed that the CHC-CMS nanogels were formed. Furthermore, the nanogels behaved as viscoelastic solids over the entire frequency range. Meanwhile, the nanogels showed excellent pH-sensitivity and high encapsulation efficiency of curcumin (89.49%–94.01%). Compared to free curcumin, curcumin encapsulated in nanogels displayed sustained release profile in simulated gastrointestinal conditions. These results suggested that the nanogels had been successfully fabricated and could be used as ideal carriers for curcumin and other bioactive compounds in functional foods.