Mild Enzyme-Induced Gelation Method for Nanoparticle Stabilization: Effect of Transglutaminase and Laccase Cross-Linking

Abstract

Low-environment-sensitive nanoparticles were prepared by enzymatic cross-linking of electrostatic complexes of dextran-grafted whey protein isolate (WPI-Dextran) and chondroitin sulfate (ChS). The effect of transglutaminase (TG) and laccase cross-linking on nanoparticle stability was investigated. Covalent TG cross-linking and grafted dextran cooperatively contributed to the stability of nanoparticles against dissociation and aggregation under various harsh environmental conditions (sharply varying pH, high ionic strength, high temperature, and their combined effects). However, fragmentation induced by laccase treatment did not promote nanoparticle stability. Structural characterization showed that the compact structure promoted by TG-induced covalent isopeptide bonds repressed dissociation against varying environmental conditions and thermal-induced aggregation. Furthermore, the increasing α-helix and decreasing random coil contents benefited the formation of disulfide bonds, further contributing to the enhanced stability of nanoparticles cross-linked by TG, whereas weak hydrophobic interactions and hydrogen bonding as evidenced by the increase in β-sheet and microenvironmental changes were not able to maintain the stability of nanoparticles treated with laccase. Encapsulated cinnamaldehyde presented sustained release from TG-cross-linked nanoparticles, and the bioaccessibility was considerably enhanced to 50.7%. This research developed a novel mild strategy to enhance nanoparticle stability in harsh environments and digestive conditions, which could be an effective delivery vehicle for hydrophobic nutrients and drug applications in food and pharmaceutical industries.

Protein Nanoparticles: Uniting the Power of Proteins with Engineering Design Approaches

“…As another work, electrostatic complexes of dextran‐grafted whey protein isolates (WPI) and chondroitin sulfate (Chs) were stabilized by TG. [ 250 ] The crosslinked complexes exhibited exceptional stability over a wide range of pH (1–10) and at high ionic strength. The complexed nanoparticles remain stable even after heating at 90 °C for 30 min.…”

Properties and thermal stability of Pickering high internal phase emulsion prepared by TGase cross‐linked collagen fibres

“…For instance, the primary, secondary, tertiary and quaternary structure of collagen will be destroyed and denatured after being heated, resulting loose structure (Wang et al ., 2017). Cross‐linking can form more stable structure for proteins (Zeugolis & Raghunath, 2011; Bansal et al ., 2021; Liu et al ., 2021a). The methods for protein cross‐linking mainly include physical, chemical and enzymatic cross‐linking, among which, enzymatic cross‐linking has been an important part for protein modification.…”

“…The methods for protein cross‐linking mainly include physical, chemical and enzymatic cross‐linking, among which, enzymatic cross‐linking has been an important part for protein modification. At present, the most widely used enzymes that can catalyse protein cross‐linking are transglutaminase (TGase), lipoxygenase, polyphenol oxidase, peroxidase and so on (Liu et al ., 2021a; Sellami et al ., 2021). Among them, one of the commonly used enzymes is TGase (Adamiak & Sionkowska, 2020).…”