Preparation, characterization, and properties of lutein block polyethylene glycol copolymer loading with lutein nanoparticles

In this paper, lutein block polyethylene glycol (lutein-b-PEG) copolymers were synthesized by hydrophilic modification of lutein with carboxylated polyethylene glycol (CT-PEG). The unreacted lutein was loaded into micelles formed by self-assembly of block copolymers to prepare composite nanoparticles. The results of FT-IR, 1 H NMR, gel permeation chromatography (GPC), UV–vis and critical micellar concentration (CMC) showed that the double terminal carboxyl group ratio of CT-PEG reached 50.31%, and lutein-b-PEG was successfully synthesized without destroying the structure of lutein. Compared with lutein, the retention rate of lutein composite nanoparticles increased from 4.32 to 81.3% after 30 days of storage in the dark. In addition, the saturation solubility and bioaccessibility of lutein nanoparticles were increased 35 times and 5.2 times, respectively, due to micellar formation and improved water solubility. These findings indicated that the lutein composite nanoparticles modified with PEG significantly improved the chemical stability, water solubility, and bioaccessibility of lutein. Graphical abstract Preparation and properties of lutein block polyethylene glycol copolymer loading with lutein nanoparticles