Enhancing the bioaccessibility of hydrophobic bioactive agents using mixed colloidal dispersions: Curcumin-loaded zein nanoparticles plus digestible lipid nanoparticles

• Mixed colloidal dispersions were developed to increase curcumin bioavailability.
• Curcumin was encapsulated in zein nanoparticles fabricated by antisolvent precipitation.
• These curcumin-loaded nanoparticles were mixed with curcumin-free lipid nanoparticles.
• The lipid nanoparticles increase the bioaccessibility of the curcumin.

The potential of mixed colloidal dispersions for increasing the bioaccessibility of a hydrophobic bioactive agent (curcumin) was examined. Curcumin was encapsulated within zein nanoparticles (fabricated by antisolvent precipitation) to obtain a high loading capacity and good chemical stability. These protein nanoparticles were then mixed with digestible lipid nanoparticles (fabricated by microfluidization) designed to increase curcumin bioaccessibility by forming mixed micelles in the small intestine. Changes in particle properties (size, charge, and organization) were measured as the mixed colloidal dispersions were passed through a simulated gastrointestinal tract: mouth; stomach; and small intestine. Curcumin bioaccessibility increased with increasing lipid nanoparticle concentration in the mixed colloidal dispersions, which was attributed to an increase in the solubilization capacity of the mixed micelle phase. This study suggests that delivery systems containing mixed colloidal particles (protein and lipid nanoparticles) may be designed to increase the bioaccessibility of lipophilic bioactive agents.