Fabrication of self-antibacterial chitosan/oxidized starch polyelectrolyte complex sponges for controlled delivery of curcumin

Herein, we present novel porous polyelectrolyte complexes (PECs) physically stabilized by electrostatic interaction between chitosan (CS) and oxidized starch of two sources, i.e. potato starch (OxPS), and rice starch (OxRS). Two strategies were employed for the preparation of PECs sponges: (i) freeze-thawing of CS aqueous solution followed by freeze-drying and adsorption of the polyanion solution, cryostructuration and freeze-drying; (ii) gradual mixing the polyanion solutions with a certain volume of CS solution under fast stirring, followed by double cryostructuration of the homogeneous dispersion, at −196 °C, and at −18 °C, extraction and freeze-drying. The PEC sponges were characterized through FTIR spectroscopy and scanning electron microscopy coupled with electron dispersive X-Ray spectroscopy (SEM-EDX). The pH-dependent swelling, erosion, and curcumin (CCM) release indicated that the preparation strategy and the starch origin strongly influenced the PEC properties and stability. It was found that the OxRS-based PECs released the CCM faster than those based on OxPS. The release mechanism of CCM was estimated by linear fitting the Higuchi, the Korsmeyer-Peppas and the first order kinetic models onto the experimental data. Furthermore, the PEC sponges exhibited self-antibacterial properties associated with the presence of CS and oxidized starch.