Development, Characterization, Stability and Bioaccessibility Improvement of 7,8-Dihydroxyflavone Loaded Zein/Sophorolipid/Polysaccharide Ternary Nanoparticles: Comparison of Sodium Alginate and Sodium Carboxymethyl Cellulose

In this study, two polysaccharides [sodium alginate (ALG) and sodium carboxymethyl cellulose (CMC)] were selected to establish zein/sophorolipid/ALG (ALG/S/Z) and zein/sophorolipid/ALG (CMC/S/Z) nanoparticles to encapsulate 7,8-dihydroxyflavone (7,8-DHF), respectively. The results showed that polysaccharide types significantly affected performance of ternary nanoparticles, including CMC/S/Z possessed lower polydispersity index, particle size and turbidity, but higher zeta potential, encapsulation efficiency and loading capacity compared to ALG/S/Z. Compared to zein/sophorolipid nanoparticles (S/Z), both ALG/S/Z and CMC/S/Z had better stability against low pH (pH 3~4) and high ionic strengths (150~200 mM NaCl). Hydrophobic effects, electrostatic interactions and hydrogen bonding were confirmed in ternary nanoparticles fabrication via Fourier-transform infrared spectroscopy. Circular dichroism revealed that CMC and ALG had no evident impact on secondary structure of zein in S/Z, but changed surface morphology of S/Z as observed by scanning electron microscope. Encapsulated 7,8-DHF exhibited an amorphous state in ternary nanoparticles as detected by X-ray diffraction and differential scanning calorimetry. Furthermore, compared to S/Z, ALG/S/Z, and CMC/S/Z remarkably improved the storage stability and bioaccessibility of 7,8-DHF. CMC/S/Z possessed a greater storage stability for 7,8-DHF, however, ALG/S/Z exhibited a better in vitro bioaccessibility of 7,8-DHF. This research provides a theoretical reference for zein-based delivery system application.

Self-Healing Hydrogels Based on Sodium Carboxymethyl Cellulose/Poly(vinyl alcohol) Reinforced with Montmorillonite

Currently, self-healing hydrogels prepared from the green process have been studied for various applications, especially in the biomedical field. This work fabricated the self-healing hydrogel based on sodium carboxymethyl cellulose/poly(vinyl alcohol)/montmorillonite by acidifying the mixture with citric acid. SEM measurements showed well-dispersed montmorillonite in the hydrogels. Cytotoxicity values >100% were seen with montmorillonite added, which indicated cell growth and no cell toxicity. Montmorillonite addition not only reinforced the networks but also improved self-healing ability. The tensile strength of the original uncut hydrogel with montmorillonite (P1C8M1) was 61 kPa, whereas the healed hydrogel showed 57 kPa. The hydrogel healed completely within 10 days, without any cracks, i.e., a 93% healing efficiency, or higher than the ~60% of the non-reinforced hydrogel. This confirmed strong hydrogen bond formation between the polymer and montmorillonite. The self-healing ability of this non-toxic hydrogel, reinforced with montmorillonite, makes it valuable for use in biomedical fields.