Impact of alginate block type on the structure and physicochemical properties of curcumin-loaded complex biopolymer nanoparticles

In this study, core-shell complex biopolymer nanoparticles loaded with curcumin were fabricated using a simple pH-driven method. An aqueous solution containing curcumin, zein, sodium caseinate, and sodium alginate was prepared under a strongly alkaline condition (pH 12) and then acidified (pH 4). This led to the formation of curcumin-loaded complex biopolymer nanoparticles with a hydrophobic core (zein) surrounded by a hydrophilic shell (caseinate-alginate). The nanoparticles formed from beta-D-mannuronic acid residues blocks (MM-blocks) had the smallest hydrodynamic diameter (202 nm), highest encapsulation efficiency (98 g/100 g), and best waterdispersibility. Transmission electron microscopy showed that the complex biopolymer nanoparticles had a core-shell structure. Fluorescence and FTIR spectroscopy were used to provide insights into the nature of the molecular hydrogen bonding and electrostatic interactions within the complex biopolymer nanoparticles. Overall, the curcumin-loaded complex biopolymer nanoparticles fabricated from MM-blocks had the best longterm storage and salt stability. These results may be useful for creating colloidal delivery systems that enhance the dispersibility, stability, and bioactivity of hydrophobic nutraceuticals.In this study, core-shell complex biopolymer nanoparticles loaded with curcumin were fabricated using a simple pH-driven method. An aqueous solution containing curcumin, zein, sodium caseinate, and sodium alginate was prepared under a strongly alkaline condition (pH 12) and then acidified (pH 4). This led to the formation of curcumin-loaded complex biopolymer nanoparticles with a hydrophobic core (zein) surrounded by a hydrophilic shell (caseinate-alginate). The nanoparticles formed from beta-D-mannuronic acid residues blocks (MM-blocks) had the smallest hydrodynamic diameter (202 nm), highest encapsulation efficiency (98 g/100 g), and best waterdispersibility. Transmission electron microscopy showed that the complex biopolymer nanoparticles had a core-shell structure. Fluorescence and FTIR spectroscopy were used to provide insights into the nature of the molecular hydrogen bonding and electrostatic interactions within the complex biopolymer nanoparticles. Overall, the curcumin-loaded complex biopolymer nanoparticles fabricated from MM-blocks had the best longterm storage and salt stability. These results may be useful for creating colloidal delivery systems that enhance the dispersibility, stability, and bioactivity of hydrophobic nutraceuticals.A