Natural Hydrogels Research Articles

Agarose Micro/Nanostructured Surfaces: A Step Toward an Innovative Solution for Platelet Storage Bags

AbstractIn addressing the critical limitations associated with platelet storage, the study investigates an innovative solution aimed at preventing the unwanted activation of platelets within storage bags. This activation is a key factor that currently restricts the shelf life of platelet products to only 72 h, leading to extreme waste production and high costs. Here, highly effective surfaces are identified for minimizing surface‐induced platelet activation. Using thermal nanoimprint lithography (T‐NIL), a new method is demonstrated for patterning reproducible agarose micro/nanostructures (a natural hydrogel with anti‐platelet adhesive properties) including dots, chains, pills, and squares. The agarose (3%) structured surfaces displayed outstanding flexibility and hydrophilic behavior that prevented platelet adhesion as confirmed by confocal microscopy. Importantly, pill‐shaped structures effectively maintained their ability to prevent platelet adhesion, even after a long cell‐contacting duration. Atomic force microscopy indicated that the effectiveness of dampening platelet adherence is determined by the shape, size, height, and aspect ratio of the structures. A model is provided to explain how the different shapes affect wettability and thereby hinder platelet adherence. The developed anti‐adhesive agarose structured surfaces show promise to revolutionize platelet storage, provide vital insights into biomaterials research, and demonstrate the potential of tailored agarose surfaces in biomedical applications.

A versatile natural gelatin-based hydrogel for emergency wound treatment through hemostasis, antibacterial, and anti-inflammation

Emergency wounds are often accompanied by bacterial infection, oxidative stress, and excessive inflammation due to the inability to quickly close and stop bleeding, resulting in chronic wounds that are difficult to heal. Clinically, surgical suturing is the fastest method for wound closure, but it is only suitable for wounds with small bleeding volumes and causes unsightly scar formation. Consequently, there is a critical need for hemostatic dressings versatile enough to address a spectrum of diverse and intricate wounds, especially in emergency scenarios. In this study, we constructed a unique versatile natural gelatin-based hydrogel with hemostasis, antibacterial, and anti-inflammation properties. The hydrogel was composed of 4-(4-(hydroxymethyl)-2-methoxy-5-nitrophenoxy) butyrylethylenediamine-modified methacrylated gelatin (GelMA-NB) and epigallocatechin gallate-grafted polylysine (EPL-EGCG), which imparts adhesion, antibacterial and antioxidant properties to the hydrogel. Simultaneously, the hydrogel was loaded with GelMA microspheres encapsulating natural resveratrol (RES@GM). This combination not only exhibited outstanding hemostatic capabilities but also preserved the anti-inflammatory potential of RES. In different animal models, the hydrogel exhibited outstanding hemostatic and wound healing effects, down-regulated the expression of IL-1βto promote inflammatory regulation and potential for angiogenesis and anti-scar. In conclusion, unique versatile natural gelatin-based hydrogel suitable for various complex wounds provides a promising strategy for emergency wound dressing applications.

Radiation synthesis of high conductivity hydrogel based on tragacanth gum/poly (ionic liquids) for multimodal sensors and supercapacitor

Natural polymer-based hydrogels have found extensive use in flexible sensing, energy storage, and other fields because of their environmental sustainability and biocompatibility. Nonetheless, numerous challenges persist in the development of hydrogels with outstanding conductivity solely from natural polymers. Herein, we have successfully synthesized hydrogels based on natural polymer (tragacanth gum) and ionic liquids (1-vinyl-3-ethylimidazolium bromide) using a convenient and efficient one-step ionizing radiation method (TG/PIL hydrogels). The TG/PIL hydrogels exhibit high ionic conductivity (7.1 S m−1 at 25 °C), and can be used for multimodal sensors, including strain and temperature sensors. It has exceptional capabilities in monitoring human motor behavior, capturing subtle facial expressions and pulses beat. TG/PIL hydrogel can also accurately sense changes in the temperature of the external environment, and have significant thermal sensitivity within the range of 40 to 60 °C (−3.22 % /°C). Furthermore, the high conductivity of TG/PIL hydrogels enables them to exhibit outstanding performance in supercapacitor electrolytes, it has good stability in a certain load bearing range, temperature range, folding angle range. This work offers a straightforward technique for creating a multimodal hydrogel sensor, with promising applications in flexible wearable devices, energy storage, and beyond.

A tissue-adhesive, mechanically enhanced, natural Aloe Vera-based injectable hydrogel for wound healing: Macrophage mediation and collagen proliferation

Macromolecule hydrogels made from natural extracts have received much attention because of their favorable biocompatibility and wound healing properties. However, their clinical applications are limited by their insufficient mechanical strength and low adhesion properties. To overcome these limitations, we developed a novel injectable Aloe vera hydrogel (PDMA-GelMA@AV). By integrating gelatin methacrylate (GelMA) and polydopamine methacrylamide (PDMA), we significantly improved the mechanical and adhesion properties of the hydrogel. The PDMA-GelMA@AV hydrogel degraded in a simulated wound environment, which was synchronized with the sustained release of the bioactive components of A. vera. In vitro and in vivo analyses revealed that this hydrogel has good biocompatibility. In vitro studies also revealed that the sustained release of the active ingredients of A. vera promoted fibroblast proliferation and migration and increased the expression of key proteins and mRNAs required for wound healing. In addition, it modulated LPS-stimulated macrophages and decreased the expression of TNF-α, IL-1β and iNOS while increasing the expression of TGF-β and ARG. In vivo experiments further confirmed the efficacy of hydrogels in wound healing applications. These findings offer a novel perspective on the application of natural macromolecules as hydrogel-based delivery vehicles in wound care.

Construction of natural hydrogels consisting of oxidized dextran, quaternized chitosan and cuttlefish ink nanoparticles for treating diabetic oral ulcers

Construction of natural hydrogels consisting of oxidized dextran, quaternized chitosan and cuttlefish ink nanoparticles for treating diabetic oral ulcers

Natural and synthetic hydrogels for dye removal

In recent years, dyes have been classified as recalcitrant contaminants in wastewater, exhibiting significant toxicological characteristics for flora, fauna, and humans. Various techniques are currently being studied for the remediation of water contaminated with dyes. Among the most relevant alternative technologies are bioadsorption, biocoagulation, the use of composite materials, advanced oxidation processes, etc. However, these methods have some disadvantages. Similarly, the use of hydrogels specifically designed for the treatment of contaminated water is a viable and effective alternative. This is due to their ability to adsorb large amounts of water, high porosity, and multiple active sites. This research describes dyes, their classification,toxicity, and ecotoxicity. Additionally, it presents some alternative treatments for water remediation, emphasizing the design of hydrogels based on synthetic and natural macromolecules. These hydrogels are proposed as promising materials for the removal of dyes from contaminated water. The aim of this research is to highlight synthetic and natural hydrogels as promising materials for the decontamination of water from dyes.

Exos-Loaded Gox-Modified Smart-Response Self-Healing Hydrogel Improves the Microenvironment and Promotes Wound Healing in Diabetic Wounds.

Wound management has always been a challenge in the clinical treatment of diabetes. In this study, glucose oxidase (GOx) is grafted onto natural pullulan polysaccharides, and oxidization is carried out to form a self-healing hydrogel using carboxymethyl chitosan by means of reversible Schiff base covalent bonding. The smart-response drug release properties of this natural self-healing hydrogel are demonstrated in diabetic wounds by taking advantage of two key factors, namely the pH-responsive nature of Schiff base bonding and the fact that GOx reduces the pH in diabetic wounds. To further enhance the biological functions of the hydrogel dressing, exosomes (Exos) are introduced into the hydrogel system. The GOx present in the hydrogel system improves the high-glucose microenvironment of diabetic wounds, releasing H2O2 to impart antimicrobial effects, and ensuring that the hydrogel realizes a smart-response function. The carboxymethyl chitosan component used to construct the hydrogel plays an effective antibacterial role. Moreover, the Exos loaded into the hydrogel effectively promotes neovascularization of the wound. The Exos also regulates macrophage polarization and reduces the levels of persistent inflammation in diabetic wounds. These results suggest that this smart responsive, multifunctional, and self-healing hydrogel dressing is ideal for the management of diabetic wounds.

Gelatin-Based Polymers Can Be Processed to Highly Resilient Biocompatible Porous Hydrogel Scaffolds for Soft Tissue Regeneration Applications

Tissue regeneration relies on the mechanical properties of the surrounding environment, and it has already been shown that mechanostimulation is highly dependent on the stiffness of the native biological tissue. The main advantage of injectable hydrogels in medical applications is their ability to be delivered through minimally invasive techniques. Natural polymer-based hydrogels have been widely used in biomedical applications, due to their high biocompatibility, low immunogenicity, and similarity to soft tissues. However, the crucial combination of low stiffness with high resilience has not been achieved for natural polymers. The current study focuses on the development of novel gelatin-based injectable hydrogels for soft tissue regeneration applications, elucidating the effects of the formulation parameters on the resilience, microstructure, biocompatibility, and mechanical properties. Non-foamed hydrogels demonstrated resilience of at least 95%, while porous hydrogels maintained resilience above 90%, allowing them to withstand mechanical stresses and dynamic conditions within the body. The adjustable modulus of these hydrogels provides the necessary flexibility to mimic the mechanical properties of soft and very soft tissues, without compromising resilience. Environmental Scanning Electron Microscopy (ESEM) observations of the porous hydrogels indicated round interconnected pore structures, desired for cell migration and nutrient flow. Biocompatibility tests on fibroblasts and pre-adipocytes confirmed high biocompatibility, both directly and indirectly. In summary, structuring these new hydrogels for achieving adjustable stiffness, along with the excellent resilience and biocompatibility, is expected to enable this new technology to fit various soft tissue regeneration applications.

A natural composite hydrogel laden with mesenchymal stromal cells for osteochondral repair: Comparison between casting and 3D bioprinting

Synovial joints, and particularly the osteochondral unit, are prone to lesions, with high risk of degeneration towards osteoarthritis. Various treatment strategies have been developed, including surgical techniques and cellular therapies, but they all show limitations. In this context, tissue engineering approaches, particularly 3D bioprinting, are promising for generating osteochondral tissue substitutes for joint repair. In this work, two biofabrication techniques, casting and extrusion-based 3D bioprinting, of an optimized formulation of a gelatin/alginate/fibrinogen bioink loaded with murine mesenchymal stromal cells (MSCs) were compared for the generation of cartilage and bone substitutes. Cell viability, proliferation and differentiation were characterized. Both techniques showed similar results in terms of viability and proliferation, but only the 3D bioprinted constructs allowed for differentiation towards the chondrogenic or osteogenic lineage using specific culture media. Bioprinting of biphasic osteochondral constructs comprising a cartilage compartment on top of a bone compartment was also explored. The study highlights the potential of our natural composite hydrogel bioink and extrusion-based 3D bioprinting for the generation of osteochondral tissue substitutes. Although further optimizations are needed, the study laid the groundwork for future advancements in osteochondral tissue engineering.

Advances of natural hydrogel-based vascularization strategies for soft tissue repair

Regeneration of soft tissues, especially those requiring complex vascularization, is a major challenge in the field of tissue engineering. The current types of tissue engineering scaffolds include sponges, electric spinning silk, hydrogels, and 3D printed biomaterials. Among them, hydrogels have the unique property of mimicking extracellular matrix (ECM), which can provide a relatively stable microenvironment for cellular activities and facilitate cell adhesion, proliferation, and differentiation; thus, have become a promising scaffold. In this paper, we present a review of the commonly used types of natural hydrogels and their applications as scaffolds in tissue vascularization. First, we enumerate the importance and advantages of several types of commonly used hydrogels of natural origin in terms of fabricating vascularized tissues or organs. Second, we discuss two different formation modalities of blood vessels, as well as natural hydrogel-based vascularization strategies, including carrying growth factors, stem cell delivery, special scaffold structures and pharmaceutical-enhanced strategy. In addition, we describe the crosslinking strategies of hydrogels as scaffolds for regeneration of vascularized soft tissues, as well as the factors affecting it. Finally, new insights are provided for the development of natural hydrogel-based vascularized soft tissue regeneration research.

Silk fibroin/chitosan thiourea hydrogel scaffold with vancomycin and quercetin-loaded PLGA nanoparticles for treating chronic MRSA osteomyelitis in rats

Chronic osteomyelitis presents significant treatment challenges, necessitating an efficient system for infection elimination and bone repair. This study developed a natural hydrogel scaffold using silk fibroin (SF) and chitosan thiourea (CST), incorporating vancomycin (VC) and quercetin (QC) loaded PLGA nanoparticles (NPs) for dual-purpose treatment. SF/CST hydrogel scaffolds exhibited homogeneous porosity and smaller interconnected pore size than pure SF and pure CST hydrogel scaffolds. Optimal PLGA/QC NPs measured 206 nm in size, displayed spherical morphology, had uniform distribution, and achieved 87 % QC loading. The release study showed sustained long-term release of VC and QC from the hydrogel scaffolds for over 20 days. Biocompatibility tests indicated that hydrogel scaffolds promoted osteoblast adhesion without cytotoxicity, with QC-containing scaffolds enhancing osteoblast growth. Antibacterial tests confirmed retained VC activity against methicillin-resistant Staphylococcus aureus (MRSA) in SF/CST. An experimental study assessed the efficacy of the hydrogel scaffolds in a MRSA-infected rat osteomyelitis model. Radiographic scores demonstrated a significant reduction for SF/CST-VC-PLGA/QC NPs compared to control, indicating reduced osteomyelitis effects. Macroscopic evaluations showed notable reductions in gross pathological effects for VC-containing groups. Histopathological assessments revealed significantly lower osteomyelitis scores and higher healing scores in the SF/CST-VC-PLGA/QC NPs, with reduced inflammatory cell infiltration and more organized connective tissue formation. In conclusion, SF/CST-VC-PLGA/QC NPs is an effective dual drug delivery system for osteomyelitis treatment, demonstrating significant antibacterial activity, enhanced bone regeneration, and reduced infection rate.

Sodium alginate-g-polyacrylamide hydrogel for water retention and plant growth promotion in water-deficient soils

Natural polymer-based hydrogels are preferred as soil water retention agents due to their inherent biocompatibility and biodegradability. Generally, these natural polymers are chemically modified by graft polymerization of vinyl monomers to improve their water absorption and retention properties. Among the polysaccharides used to prepare natural hydrogels, those based on sodium alginate (Alg) stand out for their high-water absorption and retention capacity, as well as for their ability to promote plant growth. The main objective of this study was to develop a biodegradable alginate-based hydrogel as a water retainer to promote plant growth under water deficit conditions. The synthesis was achieved by grafting poly(acrylamide) (PAM) onto Alg backbone, using bisacrylamide as chemical crosslinker and different ratios of alginate:acrylamide (Ac). In addition, Eucalyptus nitens seedlings were used as a model plant to evaluate the effect of alginate-g-polyacrylamide (Alg:PAM) hydrogel application to the growing medium on plant survival, growth, and physiological responses under both well-watered and water-deficient soil conditions. The maximum degree of swelling (65 g/g) was obtained for the hydrogel prepared. The pseudo-second order model described the water uptake kinetics of the hydrogel. The degradability of Alg:PAM hydrogel reached up to 85 % in 5 weeks in soil and occurs by breaking the glycosidic bonds of the alginate. The E. nitens seedlings cultivated with different doses of Alg:PAM hydrogel (4:1 Alg:Ac) showed higher values of height and root diameter relative growth, survival and photosynthetic responses in comparison to non-treated plants. The results indicate that Alg:PAM hydrogel (4:1 Alg:Ac) has promising applications in forestry as a water retention and seedling growth promoter under water deficient conditions.

Natural polysaccharide hydrogel with bioadhesion characters to synergistically enhance berberine's antibacterial effect by regulating the PTS system of Staphylococcus aureus

The global spread of Staphylococcus aureus (S. aureus) not only causes significant economic losses but also poses a serious threat to public health. Consequently, there is an urgent need for multidimensional strategies to develop antimicrobial dressings to combat bacterial infections. In response, we have developed a plant polysaccharide antibacterial hydrogel formed through the self-assembly of edible Kudzu powder (KP) and the natural star molecule berberine (BBR). Rheological tests show that natural polysaccharide KP-BBR hydrogel (BBR@KP) exhibits excellent injectability and adhesion. And the degradation of the hydrogel exceeded 90 % within 3 days. The synergistic effect of these two ingredients enhances the antibacterial activity of BBR and can increase the MIC of BBR to 0.05 mM. Specifically, KP promotes the affinity of the Phosphoenolpyruvate Phosphotransferase System (PTS) of S. aureus, enabling KP, with its bioadhesive properties, to adhere to the bacterial surface and continuously release BBR. Subsequently, BBR effectively exerts its antibacterial effect by inhibiting the synthesis of histidine and isoleucine. Furthermore, the BBR@KP hydrogel exhibits negligible cytotoxicity and hemolytic toxicity, underscoring its favorable biosafety profile. This synergistic natural antibacterial hydrogel, formulated through a green and straightforward methodology, not only holds promise for broad clinical applications but also provides novel perspectives for the utilization and development of plant polysaccharides in the biomedical field.

Bioprinting of Cells, Organoids and Organs-on-a-Chip Together with Hydrogels Improves Structural and Mechanical Cues.

The 3D bioprinting technique has made enormous progress in tissue engineering, regenerative medicine and research into diseases such as cancer. Apart from individual cells, a collection of cells, such as organoids, can be printed in combination with various hydrogels. It can be hypothesized that 3D bioprinting will even become a promising tool for mechanobiological analyses of cells, organoids and their matrix environments in highly defined and precisely structured 3D environments, in which the mechanical properties of the cell environment can be individually adjusted. Mechanical obstacles or bead markers can be integrated into bioprinted samples to analyze mechanical deformations and forces within these bioprinted constructs, such as 3D organoids, and to perform biophysical analysis in complex 3D systems, which are still not standard techniques. The review highlights the advances of 3D and 4D printing technologies in integrating mechanobiological cues so that the next step will be a detailed analysis of key future biophysical research directions in organoid generation for the development of disease model systems, tissue regeneration and drug testing from a biophysical perspective. Finally, the review highlights the combination of bioprinted hydrogels, such as pure natural or synthetic hydrogels and mixtures, with organoids, organoid-cell co-cultures, organ-on-a-chip systems and organoid-organ-on-a chip combinations and introduces the use of assembloids to determine the mutual interactions of different cell types and cell-matrix interferences in specific biological and mechanical environments.

Structure regulation of oxidized soybean cellulose nanocrystals/poly-acrylamide hydrogel and its application potential in wound dressing

The development of functional dressings based on natural polysaccharide-based hydrogels remains a great challenge, and the specific roles of gel composition and drug-controlled release mechanisms were unclear. In this study, oxidized soybean cellulose nanocrystals (CNCs)/poly-acrylamide (PAM) hydrogel was prepared. The proportion of CNCs, crosslinkers, and water in the system was regulated to fine-tune the rheological performances, texture properties, transparency, and micro-network structures of CNCs/PAM hydrogel, and further explored its application potential in the field of wound dressings. It was found that CNCs improved the rigidity and adhesion of hydrogels, crosslinkers improved the network density, and water promoted the softening and fluidity of hydrogels. The effective filling of CNCs in the composite hydrogel was verified by FTIR, XRD, and NMR. Furthermore, the pH responsiveness and drug-loading potential of the smart hydrogel were tested by swelling and drug-controlled release experiments, elucidating drug-release dynamic mechanisms during the wound healing process. The inhibition zones (>7 mm) of gram-positive/negative bacteria and cell viability (>100 %) assay showed satisfactory biocompatibility, as the hydrogel effectively accelerated wound healing in a wound model. These results elucidated the regulation mechanism of the structures of CNCs/PAM hydrogel and revealed the application potential of CNCs/PAM hydrogel in wound dressings.

Biocompatible chitin-based Janus hydrogel membranes for periodontal repair

Periodontal defects caused by severe periodontitis are a widespread issue globally. Guided tissue regeneration (GTR) using barrier membranes for alveolar bone repair is a common clinical treatment. However, most commercially available collagen barrier membranes are expensive and lack the antibacterial properties essential for effective bone regeneration. Herein, we report a natural polysaccharide chitin hydrogel barrier membrane with a Janus structure (ChT-PDA-p-HAP), featuring high antibacterial and protein-repelling activity on the outer side and good osteogenesis ability on the inner side. This multifunctional membrane is fabricated though a three-step process: (i) dissolution and regeneration of chitin, (ii) co-deposition with polydopamine (PDA) and poly(sulfobetaine methacrylate) (pSBMA), and (iii) coating with gelatin-hydroxyapatite (gelatin-HAP). In vitro cell experiments demonstrated the membrane's high biocompatibility and significant osteogenic activity. In vivo implantation in rats with periodontal defects revealed that the cemento-enamel junction index of the ChT-PDA-p-HAP membrane (1.165 mm) was superior to that of the commercial Bio-Gide® membrane (1.350 mm). This work presents a method for fabricating a chitin-based Janus barrier membrane, potentially expanding the use of chitin in tissue engineering. Statement of significanceThis study introduces a Janus hydrogel membrane based on chitin, tailored for guided tissue regeneration in periodontal defects. By combining antibacterial properties and osteogenic capabilities in a single membrane, the ChT-PDA-p-HAP membrane represents a significant advancement over traditional collagen barriers. Its outer surface, enhanced by Cu2+ and PDA-pSBMA coatings, resists bacterial colonization and protein adhesion effectively, while the inner side, coated with gelatin-HAP, promotes robust bone formation. In vitro experiments demonstrate high biocompatibility and substantial osteogenic differentiation, while in vivo testing in rat models confirms good therapeutic efficacy compared to commercial membranes. This multifunctional approach not only utilizes chitin's abundant natural resource but also integrates simple coating techniques to enhance therapeutic outcomes in periodontal tissue engineering, offering promising avenues for broader biomedical applications.

Cutting-Edge Hydrogel Technologies in Tissue Engineering and Biosensing: An Updated Review.

Hydrogels, known for their unique ability to retain large amounts of water, have emerged as pivotal materials in both tissue engineering and biosensing applications. This review provides an updated and comprehensive examination of cutting-edge hydrogel technologies and their multifaceted roles in these fields. Initially, the chemical composition and intrinsic properties of both natural and synthetic hydrogels are discussed, highlighting their biocompatibility and biodegradability. The manuscript then probes into innovative scaffold designs and fabrication techniques such as 3D printing, electrospinning, and self-assembly methods, emphasizing their applications in regenerating bone, cartilage, skin, and neural tissues. In the realm of biosensing, hydrogels' responsive nature is explored through their integration into optical, electrochemical, and piezoelectric sensors. These sensors are instrumental in medical diagnostics for glucose monitoring, pathogen detection, and biomarker identification, as well as in environmental and industrial applications like pollution and food quality monitoring. Furthermore, the review explores cross-disciplinary innovations, including the use of hydrogels in wearable devices, and hybrid systems, and their potential in personalized medicine. By addressing current challenges and future directions, this review aims to underscore the transformative impact of hydrogel technologies in advancing healthcare and industrial practices, thereby providing a vital resource for researchers and practitioners in the field.

Comprehensive characterization of natural polysaccharide-based hydrogels with gradient structure in concentration and stiffness

Gradient hydrogels are functionally graded biomaterials that over the last decades have garnered significant attention as valuable materials for tissue repair and regeneration. This study elucidates key factors crucially determining the character or pattern of a buoyancy-driven gradient in agarose hydrogels and also provides fundamental information regarding the complex interpretation of the formed gradient hydrogels obtained by the different characterization techniques, including rheology, UV-Vis spectroscopy, FCS, AFM, SEM. The employed techniques were successfully optimized to enhance the understanding of the gradient properties of these hydrogels. Demonstrated results showed that the agarose concentration gradient could be successfully controlled and tailored, which offers a valuable contribution to the design of gradient hydrogel. Moreover, a novel method for determining the average agarose concentration along the gradient axis is presented, improving the precision of gradient characterization. The integration of these approaches significantly enhances the comprehension of the internal structure and properties of gradient materials, contributing to advancements in their understanding and application.

Physico-Chemical and Structural Characterization of Mixed Natural Polymer Hydrogels Under Simulated Gastrointestinal Fluid

The gastrointestinal track has a varied pH, from an acidic pH in the stomach to a slightly basic pH in the intestine. The pH difference creates problems for the delivery of drugs and nutrients, as the active compounds may not survive the changing pH. Incorporating active ingredients into hydrogels can protect the compounds from degradation. Natural polymer hydrogel is preferable because of its safety and compatibility. However, a suitable formula should be optimized to facilitate suitable delivery in the gastrointestinal track. In this study, we produced hydrogels with 10 different formulas of mixed natural polymers: CMC (C), alginate (A), chitosan (X), and/or guar gum (G). The resulting hydrogels were characterized using swelling performance tests at pH 2 and 6.8, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Hydrogels with the formula of C50A25X25, C25A50X25, C25A50G25, C25A25G50, C25A50X12.5G12.5, and C25A25X25G25 are not digested at pH 2, but those hydrogels are digested at pH 6.8. The FTIR spectra of the hydrogels show functional groups of O–H, C=O, C–O, and C–H. Meanwhile, the SEM results show cracking phenomena on the surface of the hydrogels C50A25X12.5G12.5, C25A50X12.5G12.5, and C25A25X25G25. This study offers a general guide for the development of a natural polymer hydrogel as a suitable nutrient vehicle in the gastrointestinal track. Formulation of each type of nutrient should be optimized for optimum delivery to the designated part of the gastrointestinal track.

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.