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In this study, polyacrylic acid grafted lutein (PAA-g-lutein) was prepared by hydrophilic modification of lutein with polyacrylic acid (PAA) through Steglish esterification method. The unreacted lutein was loaded in micelles formed by self-assembly of graft copolymers in water to form composite nanoparticles. The bioaccessibility and bioavailability of lutein nanoparticles were studied by in vitro and in vivo digestion experiments. Compared with free lutein, the saturated solubility and bioaccessibility of lutein nanoparticles were increased by 78 times and 3.6 times, respectively. The pharmacokinetics results in the mice model showed that the maximum concentration (C max) and area under concentration-time curve (AUC) of plasma of mice were increased by 3.05 and 6.07 times with lutein nanoparticles compared with free lutein. Meanwhile, the prepared lutein nanoparticles also promoted the accumulation of lutein in the liver, mesenteric adipose, and eyeballs. These results indicate that graft copolymerization of lutein with water-soluble polymers to form nanoparticles is an effective method to promote the bioavailability of lutein in vivo. Moreover, this method is simple and applicable, and can also be used for the modification of other bioactive molecules. [Display omitted] • The graft copolymer was synthesized by hydrophilic modification of lutein with polyacrylic acid by esterification reaction. • Nanocomposite particles were prepared by graft copolymer loaded lutein for self-assembly. • In vitro simulated digestion experiments indicated that lutein nanoparticles promoted the saturation solubility and bioaccessibility of lutein. • The pharmacokinetics results in the mice model proved that the modification improved the bioavailability of lutein and sustained release. [ABSTRACT FROM AUTHOR]

The chitosan-g-polyethyleneimine-g-polyethylene glycol graft copolymer was synthesized for delivery of the immunomodulatory agent polyinosinic-polycytidylic acid and the mimetic antigen ovalbumin. The 1H-NMR results showed that polyethylene glycol was successfully grafted onto chitosan-g-polyethyleneimine copolymer by Schiff base reaction in a normal physiological environment (pH 7.4), while polyethylene glycol segments were detached from copolymer in a slightly acidic environment (pH 5.0). The results of cytotoxicity showed that graft copolymer with the modification degree of 47% had very low cytotoxicity, and the cell survival rate was above 95%. Nanoparticles of chitosan-g-polyethyleneimine-g-polyethylene glycol graft copolymer and polyinosinic-polycytidylic acid with different negative/positive charge ratios were obtained by electrostatic self-assembly between graft copolymer, polyinosinic-polycytidylic acid, and ovalbumin. The agarose gel electrophoresis results showed that polyinosinic-polycytidylic acid was well coated by the graft copolymer and protected from nuclease degradation. The performance study of nanoparticles results showed that their particle size with the negative/positive charge ratio of 40 : 1 was about 58 nm, which had the best solution stability, and the encapsulation efficiency of ovalbumin was ~50%, and it also significantly promoted the secretion of TNF-α and IFN-γ. [ABSTRACT FROM AUTHOR]

PolyI:C is an immunomodulatory agent that can be used in immunotherapy, but its transportation in the body is hindered. In this study, a chitosan (CS)- graft -polyethyleneimine (PEI) copolymer (C- g -P) is prepared by an N , N ′-carbonyl diimidazole (CDI) coupling method as a drug carrier for PolyI:C and simulated antigen ovalbumin (OVA). The results of FT-IR, 1H NMR, elemental analysis and cytotoxicity studies show that PEI is successfully grafted onto CS, and a low cytotoxicity of C- g -P- x (x = 1, 2, 3) with different PEI grafting rates are obtained. C- g -P- x -PolyI:C/OVA (C- g -P- x -PO) (x = 1, 2, 3) nanoparticles are prepared by combining C- g -P- x (x = 1, 2, 3), PolyI:C and OVA by electrostatic self-assembly. The results of agarose gel electrophoresis show that PolyI:C is well coated by the graft copolymer and protected from nuclease degradation. The results show that C- g -P-1-PO nanoparticles with graft copolymer to PolyI:C (N/P) ratios of 80:1 have the best solution stability, and the OVA encapsulation efficiency is 60.6%. The nanoparticles also have a suitable size and regular shape to be absorbed by cells. In vitro immunoassay results show that PolyI:C and OVA-loaded nanoparticles promote the secretion of tumor necrosis factor α (TNF-α) and interferon γ (IFN-γ). CS- g -PEI is a reliable drug carrier for the delivery of PolyI:C and OVA, and it also provides the possibility to carry other drugs. A chitosan- graft -polyethyleneimine copolymer (CS- g -PEI) was prepared by an N , N ′-carbonyl diimidazole (CDI) coupling method as a drug carrier for PolyI:C and simulated antigen ovalbumin (OVA). Nanoparticles of CS- g -PEI-PolyI:C/OVA with good solution stability, coating effect, immune characteristics and suitable size were prepared through electrostatic self-assembly. CS- g -PEI protected PolyI:C from nuclease degradation and is a reliable drug carrier for the delivery of PolyI:C. [ABSTRACT FROM AUTHOR]