Pickering emulsions stabilized by colloidal gel particles complexed or conjugated with biopolymers to enhance bioaccessibility and cellular uptake of curcumin

Abstract

The aim of this study was to investigate the fate of curcumin (CUR)-loaded Pickering emulsions with complex interfaces during in vitro gastrointestinal transit and test the efficacy of such emulsions on improving the bioaccessibility and cellular uptake of CUR. CUR-loaded Pickering emulsions tested were whey protein nanogel particle-stabilized Pickering emulsions (CUR-E WPN ) and emulsions displaying complex interfaces included 1) layer-by-layer dextran sulphate-coated nanogel-stabilized Pickering emulsions (CUR-DxS+E WPN ) and 2) protein+dextran-conjugated microgel-stabilized Pickering emulsions (CUR-E WPDxM ). The hypothesis was that the presence of complex interfacial material at the droplet surface would provide better protection to the droplets against physiological degradation, particularly under gastric conditions and thus, improve the delivery of CUR to Caco-2 intestinal cells. The emulsions were characterized using droplet sizing, apparent viscosity, confocal and cryo-scanning electron microscopy, zeta-potential, lipid digestion kinetics, bioaccessibility of CUR as well as cell viability and uptake by Caco-2 cells. Emulsion droplets with modified to complex interfacial composition ( i.e. CUR-DxS+E WPN and CUR-E WPDxM ) provided enhanced kinetic stability to the Pickering emulsion droplets against coalescence in the gastric regime as compared to droplets having unmodified interface ( i.e. CUR-E WPN ), whereas droplet coalescence occurred in intestinal conditions irrespective of the initial interfacial materials. A similar rate and extent of free fatty acid release occurred in all the emulsions during intestinal digestion ( p > 0.05 ), which correlated with the bioaccessibility of CUR. Striking, CUR-DxS+E WPN and CUR-E WPDxM significantly improved cellular CUR uptake as compared to CUR-E WPN ( p < 0.05 ). These results highlight a promising new strategy of designing gastric-stable Pickering emulsions with complex interfaces to improve the delivery of lipophilic bioactive compounds to the cells for the future design of functional foods.

New Insights into the Formulation and Polymerization of Pickering Emulsions Stabilized by Natural Organic Particles

“…Other linear polysaccharides, as dextran or alginate also showed ability to stabilize direct emulsions under a particulate form following a bottom-up conceptualization 64,[84][85][86] . The peculiarity of these linear polymers is that they can selfassemble into particles with very small average diameters (hundreds of nanometers) with very narrow size distributions.…”

Rheology, Microstructure, and Storage Stability of Emulsion-Filled Gels Stabilized Solely by Maize Starch Modified with Octenyl Succinylation and Pregelatinization

“…Oil-in-water (O/W) emulsions are commonly used in the food and pharmaceutical industries for protecting lipophilic nutraceuticals from adverse environmental conditions, such as pH, oxygen, and light [ 1 ]. Many researchers have recently striven to develop food emulsions stabilized by biopolymers, such as proteins, polysaccharides, and their complexes [ 2 , 3 ]. When biopolymers are applied as emulsion stabilizers, they act as emulsifiers, weighting agents, and reducing coalescence by coating oil droplets [ 4 , 5 , 6 ].…”

Controlled Release of Curcumin from HPMC (Hydroxypropyl Methyl Cellulose) Co-Spray-Dried Materials

“…Many methods have been reported to increase the solubility of curcumin and promote its bioavailability. Relative techniques include the preparation of colloids, proteinbased complexes, solid dispersions, nanoemulsions [6][7][8], and so forth. However, most of these methods have complex processes and poor physical stability and many risks such as drug leakage and potential toxicity of excipients and reagents [6], which limits the clinical application.…”