Low density lipoprotein/pectin complex nanogels as potential oral delivery vehicles for curcumin

Development of delivery systems from natural protein/polysaccharide complexes is of particularly interests for applications in food, pharmaceutics and biomedicine. In this study, novel nanogels smaller than 60 nm were prepared from egg yolk low density lipoprotein (LDL) and pectin complexation via a pH- and heat-induced facile process. The nanostructure of egg yolk LDL was elucidated for the first time under different pH conditions and its complexation with pectin was comprehensively investigated. Under optimized condition, the prepared nanogels had a diameter of 58 nm and zeta potential of -41 mV, with spherical shape, smooth surface, and homogeneous size distribution, as evidenced by dynamic light scattering, scanning and transmission electron microscopes. The Fourier transform infrared spectrum revealed that hydrophobic and electrostatic interactions were the driving forces to form nanogels. The innovative Nano Spray Drying technology was studied and optimized to obtain nano-size powder of nanogels which exhibited excellent re-dispersibility in water, overcoming the drying challenge (irreversible gelation) of egg yolk LDL and greatly expanding its practical applications. Curcumin was adopted as a model compound to investigate the drug delivery potential of LDL/pectin nanogels. The mass ratio of curcumin/LDL played an essential role in determining the particle size and encapsulation efficiency. The LDL/pectin nanogels had excellent stability under simulated gastrointestinal conditions with the presence of digestive enzymes and enabled controlled release of curcumin. The novel LDL/pectin nanogels have promising features for oral delivery of nutrients and drugs. (C) 2016 Elsevier Ltd. All rights reserved.