In spite of the numerous advantages of polymer nanoparticles as oral drug delivery systems, they are suffering due to their poor resistance to the harsh gastrointestinal (GI) environments which largely restrict their applications. We report here the synthesis, purification and characterization of food nutraceuticals composed caseinophosphopeptide (CPP)-chitosan (CS) nanoparticles that were covalently cross-linked with genipin, and their structure behavior in the harsh pH and enzyme conditions in GI tract. Genipin cross-linked the CPP-CS nanoparticles internally, with little influence on their particle size and surface charge. Optimal purification of the nanoparticles from the reaction system was achieved by centrifugation operating at 2500 g for 45 min, after which, the nanoparticles could be re-dispersed with the similar physicochemical properties as their parental ones. Furthermore, the cross-linking reaction with different genipin concentrations and different reaction time were confirmed and characterized by Fourier-transform infrared spectroscopy (FT-IR). Cross-linking with genipin successfully extended the CPP-CS nanoparticles' effective scope through the entire GI pH conditions, preventing their burst in stomach acidic and their precipitation under neutral intestinal environment. Pepsin in stomach showed little impact on the colloid stability of the nanoparticles, however, trypsin in intestinal fluid induced their aggregations. The genipin cross-linked CPP-CS nanoparticles demonstrated low cytotoxicity in both human gastric BGC823 and intestinal HT29 cell cultures. Therefore, cross-linking with genipin is a simple and green method to endow the polymer nanoparticles with strong resistance to harsh GI environment, and the novel nanoparticles composed with food nutraceuticals show promise as an efficient and edible oral delivery vehicle of therapeutics.

Food nutraceuticals composed polymer nanoparticles with high resistance to the harsh gastrointestinal environments: Synthesis, purification, and structure characterization

248th National Meeting (2014)

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