Physicochemical and morphological transformations of chitosan nanoparticles across the gastrointestinal tract and cellular toxicity in an in vitro model of the small intestinal epithelium.

Nanoscale chitosan materials exhibit nano-specific properties that make them useful in agri-food and biomedical applications. Chitosan nanoparticles (Chnps) are being explored as nanocarrier platforms to increase oral bioavailability of drugs and nutraceuticals, but little is known of their fate and transformations in the gastrointestinal tract (GIT), or of their potential toxicity. Here, the fate in the GIT of Chnps, soluble starch-coated Chnps (SS-Chnps), and bulk chitosan powder (Chp) and their cytotoxicity, were assessed using a simulated digestion and a cellular model of the small intestinal epithelium. Physico-chemical characterization revealed dissolution of Chp, but not of Chnps or SS-Chnps, during the gastric phase of digestion, stability of the starch coating of SS-Chnps in the oral and gastric phases, and agglomeration of all materials during the small intestinal phase. A slight but significant (10%, p<0.01) increase in cytotoxicity (LDH release) was observed with exposure to digested Chnps, but not Chp or SS-Chnps.