Hemp Protein Isolate-Based Natural Thermal-Reversible Hydrogel as a Novel Wound Dressing Material.

Hydrogels, due to their excellent microstructure and mechanical strength, have become a novel biomaterial in wound dressing. However, plant proteins have never been considered because of their poor original gelling performances and insufficient rheological properties. Here, we reported the fabrication of a plant protein-based thermal-reversible gel using a reverse micelle-extracted hemp protein isolate (HPI). A systematic study was conducted to fully reveal their microstructure, rheological properties, and anti-inflammatory effect to lay a foundation for this newly developed plant protein hydrogel as a potential natural wound dressing. By modulating protein concentration (4% HPI) and temperature (85 °C), a thermal-reversible HPI gel appeared as a filament structure with the major molecular driving force of hydrophobic interactions and hydrogen bonds. By characterizing the rheological properties, lower gel strength and wider linear viscoelastic regime were determined in the thermal-reversible HPI gel compared with a thermal-irreversible HPI gel. Besides, large amplitude oscillatory shear data identified the thermal-reversible gel as a soft gel which demonstrated intracycle strain stiffening and shear thinning behavior. Moreover, the thermal-reversible HPI gel is nontoxic and has benefits in neutrophil growth with injectability and perfect wound coverage. This study opens a novel means to form a natural thermal-reversible hydrogel that can be a new material source for wound dressing.

Antifungal activity, mycotoxin inhibitory efficacy, and mode of action of hop essential oil nanoemulsion against Fusarium graminearum.

This work aims to investigate antifungal, mycotoxin inhibitory efficacy of the hop essential oil (HEO) nanoemulsion and their mode of action (MOA) against Fusarium graminearum isolate, a fungal pathogen causing Fusarium Head Blight (FHB) in cereal crops. The HEO, primarily consisting of terpenes and terpenoids, was encapsulated in nanoemulsion droplets. Physically stable HEO-in-water nanoemulsion was fabricated using 0.5 wt% of tween 80 and 5 wt% oil phase comprising 30 % of Ostwald ripening inhibitor and 70 % of HEO. In terms of antifungal effect, HEO nanoemulsion could not only effectively inhibit mycelial growth and spore germination of F. graminearum isolates, but also remarkably suppress the production of deoxynivalenol (DON) and its derivatives in rice culture by applying 750 µg of HEO/g rice. Our studies on the MOA showed that HEO nanoemulsion could alter the contents of total lipid and chitin in outer cell membrane as well as damaging cytoplasmic membrane.

Alginate-based double-network hydrogel improves the viability of encapsulated probiotics during simulated sequential gastrointestinal digestion: Effect of biopolymer type and concentrations.

The impact of secondary polysaccharide, i.e., low methoxyl pectin (LMP) or κ-carrageenan (KC), and its concentration (0.2, 0.4, and 0.6%) on particle size, shape, morphological, textural properties and swelling behavior of sodium alginate (ALG)- based double-network hydrogel particles, as well as the viability of encapsulated probiotics Lactobacillus rhamnosus GG (LGG) in simulated sequential gastrointestinal (GI) digestion was investigated. We found the addition of LMP impaired the sphericity of double-network hydrogel particles, while the incorporation of KC increased the particle size. The FT-IR results indicated the miscibility and cross-linking capacity of the two polysaccharides in forming double-network hydrogel particles. With respect to the swelling behavior in simulated GI digestion, all hydrogel particles shrank in simulated gastric fluid (SGF) but swelled in simulated intestinal fluid (SIF). Among the two types of double-networking, ALG-KC hydrogel particles showed noticeable shrank in SGF in conjunction with the reduced swelling in SIF, which was unfavorable for protection and the controlled release of probiotics. In the case of death rate of encapsulated LGG, the presence of LMP at a lower level (0.2 or 0.4%) exhibited protective effect against LGG death during the sequential GI digestion, while addition of KC demonstrated an opposite role.

Spatial Distribution and Solvent Polarity-Triggered Release of a Polypeptide Incorporated into Invertible Micellar Assemblies.

Extracting, stabilizing, or delivering biomacromolecules such as proteins and peptides in organic phases have potential applications in biocatalysis, protein extraction, and food antioxidation. However, most current delivery/stabilization platforms face various limitations such as protein/peptide molecular size, platform stability/reusability, and/or potential damage to the cargos. A potential solution to these problems is micellar self-assemblies from amphiphilic invertible polymers, which have recently been demonstrated to be powerful as molecular hosts to deliver both small molecular drugs and functional polypeptides in the aqueous phase. To better understand the function of biomacromolecules and predict the usefulness of the formed invertible micellar assemblies (IMAs) as biomacromolecular hosts in organic phases, it is critical to characterize the spatial distribution, structure, and dynamics of biomacromolecules in the IMA including those upon release. However, the background signals of the IMAs limit the application of most peptide characterization approaches. In this work, we overcome the technical barriers by using site-directed spin labeling electron paramagnetic resonance to probe the spatial arrangement and release of a model, the hemagglutinin (HA) peptide, in the IMAs formed from two different amphiphilic invertible polymers. By site-specifically probing three residues along the peptide chain, for the first time, we depict the possible spatial distribution of HA within the IMAs. By triggering the disassembly of the IMAs with a thermodynamically good solvent (in this study, acetone), we detailed the stability of IMAs in toluene and the peptide release conditions once the polarity of the medium changes. Our findings are important for the application of peptides/proteins at the polar-nonpolar interface or using this interface to extract or deliver biomacromolecules. Our work also demonstrates the power of SDSL-EPR on probing peptide or micelle dynamics, which can be generalized to understand proteins or other biomacromolecules in micellar polymer assemblies in varied applications.

[Study on all-round evaluation of biocompatibility of biomaterial].

Biocompatibility has always been the focal point in the study of biomaterials applied to medical apparatus. But at present, the standard system hasn't formed completely to evaluate the biomaterials. In recent years scientists tend to use general standard of evaluation. In this article, based on the recalcification time, the adhesion of platelets as well as the total quantity of plasma protein and some other evidences, combining with the Analytic hierarchy process (AHP), the method of general evaluation on the biocompatibility of anticoagulant biomaterials was discussed.

[Characterization of anticoagulant biomaterial and its development].

Good anticoagulant biomaterials need good surface chemical properties, good mechanics performances and particularly good characteristics of biocompatibility, including tissue compatibility and hemocompatibility. In order to understand with greater clearness the anticoagulant biomaterial, we have to characterize them by different methods. In this paper, the approaches to assessing and displaying the characteristics of anticoagulant biomaterial are reviewed in three aspects, namely the surface chemical properties and structure, the mechanics performances the and the biocompatibility of anticoagulant biomaterial.

Stabilization of soybean oil bodies by enzyme (laccase) cross-linking of adsorbed beet pectin coatings.

Soybean oil bodies are naturally coated by a layer of phospholipids and oleosin proteins, which protect them from in vivo environmental stresses. When oil bodies are incorporated into food products, they encounter new environmental stresses such as changes in pH, ionic strength, and temperature. Consequently, additional protection mechanisms are often needed to stabilize them. The purpose of this study was to determine whether soybean oil bodies could be stabilized by coating them with a layer of cross-linked anionic polysaccharide (beet pectin). The beet pectin layer was cross-linked via its ferulic acid groups using laccase (an enzyme that catalyzes the oxidation of phenolic groups). Oil body suspensions were prepared that contained 1 wt % oil and 0.06 wt % beet pectin at pH 7 and were then adjusted to pH 4.5 to promote electrostatic deposition of the beet pectin molecules onto the surfaces of the oil bodies. Laccase was then added to promote cross-linking of the adsorbed beet pectin layer. Cross-linked pectin-coated oil bodies had similar or better stability than uncoated oil bodies to pH changes (3 to 7), NaCl addition (0 to 500 mM), and freeze-thaw cycling (-20 °C for 22 h; +40 °C for 2 h). These pectin-coated oil bodies may provide a convenient means of incorporating soybean oil into food and other products.