Gelation Mechanism Research Articles

Tailoring the properties of castor oil polyurethanes organogels with green oligoesters

Castor oil (CO) can react with isocyanate to form polyurethane organogels, whose hydrophobicity can be regulated by functionalization with “green” oligoesters of bio-dicarboxylic acids. Here, we elucidated the gelation mechanism induced by the oligoesters to gain control of the gels’ mechanical properties and solvent confinement capacity. This can be useful in cleaning Cultural Heritage items, a socioeconomically important application, and other scientific/technological sectors. During gelation, the oligoesters react with isocyanate to form aggregates whose compatibility with CO is regulated by the oligoesters’ hydrophobicity. This allows fine control of gelation time and of the gels’ micro- and nanostructure structure, where the presence of oligoesters in solid-like regions regulates rheological behaviour and mechanical resistance. The gels’ solvent upload capacity also depends on the oligoesters’ hydrophobicity, which can favour chain relaxation over Fickian diffusion during swelling. Finally, the swollen organogels were used to remove organic varnishes/coatings from painted wood and glass, demonstrating potential as sustainable cleaning tools for works of art.

Effect of Chemical Composition of Metal-Organic Crosslinker on the Properties of Fracturing Fluid in High-Temperature Reservoir.

To investigate the effect of the chemical composition of a metal-organic crosslinker on the performances of fracturing fluid in high-temperature conditions, four zirconium (Zr) crosslinkers and one aluminum-zirconium (Al-Zr) crosslinker with a polyacrylamide were used. The crosslinkers possessed the same Zr concentration, but they differed in component amounts and the order of the addition of the crosslinker components, leading to different chemical compositions in the crosslinkers. The fracturing fluids prepared by different tested crosslinkers were compared in terms of properties of rheological behavior, sand-carrying ability, microstructure, and gel breaking characteristics. The results showed that the fracturing fluids prepared by zirconium lactic acid, ethanediamine, and sorbitol crosslinkers offered the slowest viscosity development and highest final viscosity compared to the zirconium lactic acid crosslinker and the zirconium lactic acid and ethanediamine crosslinker. The zirconium sorbitol, lactic acid, and ethanediamine crosslinker exhibited a faster crosslinking rate and a higher final viscosity than the zirconium lactic acid, ethanediamine, and sorbitol crosslinker; the crosslinker showed crosslinking density and crosslinking reactivity, resulting in more crosslinking sites and a higher strength in the fracturing fluid. The Al-Zr-based crosslinker possessed better properties in temperature and shear resistance, viscoelasticity, shear recovery, and sand-carrying ability than the Zr-based crosslinker due to the synergistic crosslinking effect of aluminum and zirconium ions. The tertiary release gelation mechanism of the Al-Zr-based fracturing fluid achieved a temperature resistance performance in the form of continuous crosslinking, avoiding the excessive crosslinking dehydration and reducing viscosity loss caused by early shear damage. These results indicated that the chemical compositions of metal-organic crosslinkers were important factors in determining the properties of fracturing fluids. Therefore, the appropriate type of crosslinker could save costs without adding the additional components required for high-temperature reservoirs.

Sustained release behavior of lysozyme based on konjac glucomannan/κ-carrageenan composite hydrogels

In this study, the gelation mechanism of konjac glucomannan (KGM)/κ-carrageenan (KC) composite hydrogels at different mass ratios and its controlled release ability to lysozyme (Ly) were investigated. With the increase of KGM proportion, water holding capacity (WHC) and hardness first increased and then decreased, and reached the maximum when the mass ratio of KGM to KC was 1:2. Rheological tests showed that the viscoelasticity of the composite hydrogels can be effectively adjusted by changing the mixing ratio of KGM and KC. Fourier transform infrared spectroscopy (FTIR) and thermogravimetry confirmed that the thermal stability of the composite hydrogels was enhanced by hydrogen bonding as the main interaction force between KGM and KC. The porous gel network was observed by scanning electron microscope (SEM). With the increase of KGM ratio, the pore size first decreased and then increased. In addition, adjusting the ratio of KGM and the pH of release environment can enhance the controlled release effect of KC on Ly by the in vitro release experiment of Ly. Overall, these findings provide a theoretical basis for the development of performance-enhanced composite hydrogels for drug-controlled release.

Underlying the mechanisms of incorporation of κ-carrageenan on the formation of low-salt myofibrillar protein gels during heating process: Perspective on the dynamic changes of protein structures and molecular interactions

This study aimed to systematacially investigate the effects of κ-carrageenan (KC) concentration on the formation of myofibrillar protein (MP) gels under low-salt condition based on the dynamic changes of protein structures and molecular interactions during heating process. The results indicated that incorporating KC markedly improved the water holding capacity (WHC) and gel strength of MP gels (P < 0.05). Those properties were most improved by adding 0.4% KC with WHC of 71.44% and gel strength of 1.62 N. During the heating process, when the temperature was above 50 °C, KC addition significantly increased the turbidity and particle size and decreased solubility of MP in a concentration-dependent manner, as well as exhibiting higher surface hydrophobicity at 0.2% KC concentration (P < 0.05), indicating that KC accelerated the rate of aggregation of MP during heating process. The dynamic rheological behaviors indicated that the addition of KC promoted the early unfolding and aggregation of MP at a relatively lower temperature, which was verified by the fluorescence denaturation mechanism results. Moreover, the addition of KC significantly promoted the heat-induced conformational transition of MP from α-helix companied with β-sheet and β-turn, which was due to the interaction between MP and KC accelerating the formation of MP gels during the heating process. Intermolecular forces results revealed that the aggregation of myosin head and cross-linking of myosin tail of MP added KC was enhanced by ionic bonds, hydrophobic interactions, and disulfide bonds, which facilitated the better gel performance. Our present results provided a comprehensive understanding of gelation mechanism of MP-KC mixed gels under low-salt condition, with implications for the practical application of KC in meat processing.

Gelation behavior and mechanism of low methoxyl pectin in the presence of erythritol and sucrose: The role of co-solutes

Co-solutes such as sucrose and sugar alcohol play a significant part in low methoxyl pectin (LMP) gelation. To explore their gelation mechanism, we investigated the gelation behavior of LMP in the presence of erythritol and sucrose with Ca2+. Results revealed that the introduction of erythritol and sucrose improved the hardness of the gels, fixed more free water, accelerated the rate of gel structuring, and enhanced the gel strength. FT-IR confirmed the reinforced hydrogen bonding and hydrophobic forces between the pectin chains after introducing co-solutes. And it could be observed clearly by SEM that the cross-linking density of gel network enhanced with co-solutes. Furthermore, gel disruption experiments suggested the presence of ionic interaction, hydrogen bonding, and hydrophobic forces in LMP gels. Finally, we concluded that the egg-box regions cross-linked only by LMP and Ca2+ were too weak to form a stable gel network structure. Adding co-solutes could increase the amount of cross-linking between pectin chains and enlarge the cross-linking zones, which favored the formation of a dense gel network by more hydrogen bonding and hydrophobic forces. Sucrose gels had superior physicochemical properties and microstructure than erythritol gels due to sucrose's excellent hydration capacity and chemical structure characteristics.

Use of ozone oxidation in combination with deacetylation for improving the structure and gelation properties of konjac glucomannan

In this study, oxidized deacetylated konjac glucomannans with different degrees of oxidation were prepared by a combination of deacetylation and ozone oxidation. Carboxyl groups were found to be introduced into the modified konjac glucomannan while acetyl groups were removed. The backbone, branched chains, and crystal structure of modified konjac glucomannan were not significantly affected. The whiteness was enhanced to 97–99 % and the thermal degradation temperature was up to 250 °C after modification. The solubility of the modified konjac glucomannan (oxidized for 60 min) was significantly increased to 84.56 % (p < 0.05), while its viscosity and swelling power were notably decreased owing to the changes in molecular weight (from 106 to 104) and functional groups. Rheological analysis showed that oxidized deacetylated konjac glucomannan has the ability to form soft-textured gels and the potential to develop dysphagia foods. Future studies should focus on the gelation mechanisms of oxidized deacetylated konjac glucomannan.

RETRACTED: The current advances, challenges, and future trends of plant-based yogurt

BackgroundRising global population and protein demand challenge traditional animal protein sources, emphasizing sustainability and environmental concerns. Plant proteins emerge as viable, eco-friendly alternatives, spotlighting plant-based yogurts (PBYs) for their potential. However, their broader acceptance hinges on overcoming the challenges of taste, functionality, and nutrition. Addressing these is crucial for their market success. Scope and approachThis review summarizes the mechanisms of gel formation and flavor generation in PBYs made from various plants compared to milk-based yogurts (MBYs) produced from traditional animal milk. It discusses the current state and challenges of PBY research, including aspects of processing, nutrition, and product quality. Based on this, future research directions for PBYs are proposed. Key findings and conclusionsThe texture and flavor of PBYs are influenced by plant proteins' gelation and fermenting microbes' metabolic activities. Compared to MBYs, PBYs offer unique nutritional benefits, such as higher unsaturated fatty acid content and lower cholesterol levels. However, challenges remain in achieving the desired taste and texture, as well as addressing consumer concerns about anti-nutritional factors and nutritional imbalances in some plant sources. Future research should focus on broadening raw materials, applying new technologies, product innovation, strain selection, nutritional enhancement, health function studies, sensory optimization, and gelation mechanism exploration to advance plant-based food sustainability.

Thermosensitive injectable polysaccharide-based hydrogels: Gelation mechanisms, synthetic strategies, biomedical applications, and challenges

In recent years, thermosensitive polysaccharide-based injectable hydrogels have gained increasing attention in biomedical applications, including wound healing, drug delivery, and cartilage repair. These hydrogels have favorable biocompatibility, biodegradability, and tunable physical and chemical properties. Thermosensitive polysaccharide-based injectable hydrogels are a class of intelligent soft matter material. They can undergo a reversible liquid-solid transition when exposed to temperature stimuli. Therefore, their precursor solutions can be accurately inserted into target sites with irregular geometries in a minimally invasive way and then transformed into gels in situ by the organism’s temperature stimulation to deliver biologically active molecules. This review summarizes the recent developments of thermosensitive injectable polysaccharide-based hydrogels. The focus is on the mechanism of sol-gel phase transition, as well as the design and preparation of thermosensitive polysaccharides and their applications in biomedical fields. In addition, the outlook of the challenges in biomedical applications is provided at the end of the paper.

Impact of α-, β-, γ-cyclodextrins on recyclable catalytic reduction of silver nanoparticles loaded on cyclodextrin/alginate

Metallic nanoparticles (MNPs) synthesized through the ionotropic gelation mechanism using alginate (Alg) and cyclodextrins (CDs) have exhibited remarkable efficacy in physicochemical characterization and catalytic performance in the recent reports. This study delves into the impact of cyclodextrin structures on the synthesis, properties, and recyclable catalytic capabilities of nanocomposites containing silver nanoparticles (AgNPs) loaded onto CDs/Alg. The AgNPs were biogenically synthesized using an aqueous extract of Arctium lappa as a green reductant. Varying CDs led to AgNPs with mean sizes ranging from 7.0 to 18.0 nm within the nanocomposites. The crystalline structure of AgNPs was confirmed through HRTEM and SAED measurements. The recyclable catalytic potential of the nanocomposites was assessed for the reduction of toxic organic compounds, including 4-nitrophenol, methyl orange, and rhodamin B. Notably, the AgNPs@α-CD/Alg nanocomposite emerged as an outstanding catalyst, excelling in both catalytic performance and recyclability. These results underscore the substantial impact of cyclodextrin structure on the catalytic properties and efficiency of AgNPs-based nanocomposites.

Effects of cellulose diameter on the formation and rheological properties of edible walnut oleogels structured by cellulose nanofiber

Oleogel of edible vegetable oils structured by cellulose nanofiber (CNF) via emulsion-templated method has attracted many interests due to its potential substitute of saturated or trans-fats in food industry. The gelation mechanism of liquid oil is dominated by different intermolecular non-covalent interactions, while the type and strength of these interactions are greatly influenced by the structure and properties of the gelator factors. Here, the effect of different CNF diameter ranges (5–10 nm, 10–20 nm and 20–60 nm) was investigated for CNF-based walnut oil oleogels, under the same fiber length and surface carboxyl content of CNFs. The results showed that CNFs with diameters of <20 nm exhibited better emulsification properties, and effectively restrained droplet size increasing and aggregation, compared to CNF with diameter of 20–60 nm. The resultant oleogels with smaller CNF diameter exhibited higher oil-binding capacity (OBC, ∼85%) and better thermal stability of the resultant oleogels. More compact structure and stronger mechanical strength of oleogels were achieved with CNF diameters of <20 nm, which was verified by stronger textural hardness of the oleogels (0.46 N), as well as higher storage modulus (up to 1.1 × 105 Pa) and apparent viscosity in rheological measurement. The enhanced OBC and structure strength of oleogels with smaller CNF diameter could be attributed to the enhanced hydrogen bonding interactions between CNF molecules and CNFs with oil molecules during oleogelation, as the rigorously fibrillation exposed more surface hydroxyl groups as accessible hydrogen bonding sites during CNF preparation. This study improved the understanding about gelling properties of CNFs with different fiber diameters and provided an empirical basis for the construction of CNF-based oleogels with tunable hydrogen bonding interactions.

ABC block copolymer micelles driving the thermogelation: Scattering, imaging and spectroscopy

Thermoresponsive polymers have attracted much scientific attention due to their capacity for temperature-driven hydrogel formation. For biomedical applications, such as drug delivery, this transition should be tuned below body temperature to facilitate controlled and targeted drug release. We have recently developed a thermoresponsive polymer that forms gel at low concentrations (2 w/w%) in aqueous media and offers a cost-effective alternative to thermoresponsive systems currently being applied in clinics. This polymer is an ABC triblock terpolymer, where A, B, and C correspond to oligo(ethylene glycol) methyl ether methacrylate with average Mn 300 g mol−1 (OEGMA300), n-butyl methacrylate (BuMA), and di(ethylene glycol) methyl ether methacrylate (DEGMA). To investigate the self-assembly and the gelation mechanism in diluted solutions, we used small-angle neutron scattering (SANS) on 1 w/w% (below the gelation concentration) and 5 w/w% solutions (above the gelation concentration). As a comparison, we also investigated the solutions of the most studied thermoresponsive polymer, namely, Pluronic F127, an ABA triblock bipolymer made of ethylene glycol (A) and propylene glycol (B) blocks. SANS revealed that the in-house synthesised polymer forms elliptical cylinders, whose length increases significantly with temperature. In contrast, Pluronic F127 solutions form core-shell spherical micelles, which slightly elongate with temperature. Transmission electron microscopy images support the SANS findings, with tubular/worm structures being present. Variable-temperature circular dichroism (CD) and proton nuclear magnetic resonance (1H NMR) spectroscopy experiments reveal insights on the tacticity, structural changes, and molecular origin of the self-assembly.

Copper Ion-Inspired Dual Controllable Drug Release Hydrogels for Wound Management: Driven by Hydrogen Bonds.

Bacterial infections and inflammation progression yield huge trouble for the management of serious skin wounds and burns. However, some hydrogel dressing exhibit poor wound-healing capabilities. Additionally, little information is given on the molecular theory of hydrogel gelation mechanisms and drug release performance from drug-polymer network in the water environment. Herein, cationic guar gum (CG) is first mixed with dipotassium glycyrrhizinate (DG), and then crosslinked Cu2+ to strengthen the mechanical strength followed by encapsulating mussel adhesive protein (MAP) as composite dressings. Intriguingly, CG-Cu2+ 0.5-DG10 possessed proper rheological properties and mechanical strength predominantly driven by strong CG-H2O-Cu2+ and Cu2+-CG hydrogen bonding interaction. Weak DG-CG hydrogen bonding only controlled DG release in the initial 4 h, while strong hydrogen bonding is the main force regulating the sustained release of Cu2+ within 48 h. The incorporation of MAP further loosened the tight crosslinking of CG-Cu2+ 0.5-DG10. The screened CG-Cu2+ 0.5-DG10/MAP possessed excellent self-healing, injectability, antibacterial, anti-inflammatory, cell proliferation-promotion activities with high biocompatibility. Therefore, CG-Cu2+ 0.5-DG10/MAP hydrogel expedited wound closure on S. aureus-infected full-thickness skin wound model and lowered necrosis progression to the unburned interspaces on a rat burn model. The results highlight the promising translational potential of Cu2+-inspired hydrogels for the management of burns and infected wounds.

Effect of salting and dehydration treatments on the physicochemical and gel properties of hen and duck egg yolks, plasma and granules.

Salted hen egg yolks are less oily and less flavorful than salted duck egg yolks. However, hen eggs have a more adequate market supply and have a broader application prospect than duck eggs. In the present study, egg yolks, plasma, and granules were dehydrated by adding 1% NaCl to simulate traditional curing process of salted egg yolk. The changes in the pickling process of hen egg yolks (HEY) and duck egg yolks (DEY) plasma and granules were compared to reveal the gelation mechanism and the underlying causes of quality differences in salted HEY and DEY. Salted HEY can be compared with the changes in DEY during the pickling process to provide a theoretical basis for the quality improvement of salted HEY to salted DEY. The results showed that both plasma and granules were involved in gel formation, but exhibited different aggregation behaviors. Based on the intermolecular forces, the HEY proteins achieved aggregation mainly through hydrophobic interactions and DEY proteins mainly through covalent binding. According to spin-spin relaxation time, HEY gels immobilized a large amount of lipid and interacted strongly with lipids. DEY gels showed much free lipid and had weak interaction with lipid. The microstructure showed that HEY proteins were easily unfolded to form a homogeneous three-dimensional gel network structure after salting, whereas heterogeneous aggregates were formed to hinder the gel development in DEY. Changes in protein secondary structure content showed that pickling can promote the transformation of the α-helices to β-sheets structure in HEY gels, whereas more α-helices structure was formed in DEY gels. The present study has demonstrated that different gelation behaviors of hen and duck egg yolk proteins (especially in plasma) through salting treatment led to the difference in the quality of salted HEY and DEY. © 2024 Society of Chemical Industry.

Progress of Carrageenan‐Based Films and Coatings for Food Packaging Applications

ABSTRACTAs a polysaccharide extracted from marine red algae, carrageenan has the advantages of biodegradability, nontoxicity and water solubility over petroleum‐based plastics for use as films and coatings for keeping food fresh. Aqueous solutions of carrageenan can be cast into films on plates and then made into food packaging bags, as well as coated directly onto food surfaces, all of which are referred to as ‘wraps’. To overcome the inherent limitations of carrageenan as a packaging material, physical and chemical modifications have been studied. The mechanical, thermal, barrier and antibacterial properties of modified carrageenan make it widely applicable for extending the shelf life of food products and monitoring its freshness. The research progress of carrageenan‐based wraps in recent years has been reviewed in terms of preparation methods, physicochemical properties, gelation mechanisms and applications, and the factors affecting the drying rate of them have been analysed. Finally, applications and future research directions of carrageenan are summarized and discussed to provide useful guidelines for further research.

Interaction mechanism and binding mode between different polyphenols and gellan gum

To investigate the impact of different polyphenols on the gel properties of gellan gum (GG) and the interaction mechanism, experiments and virtual molecular simulations were conducted based on nine representative polyphenols. Rheological analysis revealed that all the GG/polyphenol composite hydrogels were pseudoplastic fluids with a low viscosity. The storage modulus (G′) of hydrogel containing only GG was 28.3 Pa at 0.1 Hz. The addition of gallic acid (GA), puerarin (PUE) or cyanidin cation (CC) significantly increased the G′ of the hydrogel by 4.9-fold, 3.3-fold, and 2.6-fold, respectively. The introduction of GA reduced the water holding capacity (WHC) of the hydrogel to 62.0 %, while the other eight polyphenols increased the WHC to nearly 100 %. Regular, intact and dense honeycomb mesh structures were observed in the GG/GA, GG/PUE, GG/CC and GG/catechin microstructures. The molecular docking results indicated that, among the nine polyphenols, PUE had the strongest affinity for GG with an interaction energy of −18.64 kcal/mol. According to the results of molecular dynamics simulation, the total energy of the composite system interacting with water corresponded well with the G′ of the composite hydrogels. The GG/GA system with the highest G′ had the lowest total energy of −15655.82 kJ/mol. Hydrogen bonds were the main driving force for improving the strength and maintaining the structural stability of the composite hydrogels. Therefore, this study confirmed the various effects of nine polyphenols on GG hydrogels and provided a novel basis for investigating the synthesis and gelation mechanism of polysaccharide-polyphenol composite hydrogels.

Labile assembly of a tardigrade protein induces biostasis.

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Preparation and Mechanistic Exploration of Fermented Shrimp Surimi Gel Utilizing Enterococcus lactis S-15

This study aimed to utilize Enterococcus lactis S-15 for the preparation of fermented shrimp gels. The gel properties and the gelation mechanism of proteins were investigated under acid-induced denaturation and protein degradation, and the quality of the gel was evaluated. Results showed that the pH of the shrimp surimi decreased from 7.35 to 4.74. The optimal gel strength observed at 24 h of fermentation was 326.41 g × cm, and disulfide bonds played a crucial role in the fermented gel. The fermented gel exhibited higher cooking loss rates and freeze-thaw loss rates compared to the heat-induced gel (control). However, fermented gels exhibited high overall acceptability both before and after cooking. The volatile basic nitrogen content in the fermented gel remained below 28.00 mg/100 g, within the safe range, and no histamine was detected. The results provide valuable data for the development and reprocessing of fermented shrimp surimi gel.

Nanotechnology at Work: Hydrogel Drug Delivery Architectures

Hydrogels represent three-dimensional, interconnected networks known to absorb substantial amounts of H2O but at the same time, being insoluble in the aforementioned solvent. Their exceptional hydrophilic nature, biocompatibility and diverse therapeutic potential position them as highly promising biomaterials within biological and biomedical fields. These materials, on account of their innoxious innate characteristics and safe utilization, have garnered widespread acceptance across tremendous and diverse biomedical applications ranging from traditional therapies to state-of-the-art advancements. This extensive review incorporates a spectrum of varied types of hydrogels, elaborating on both their chemical, physical aspects and also throws light on the rheological, analytical and spectroscopic tools employed for their characterization. It also continues to elaborate on the various mechanisms of gelation for facilitating a better understanding of the topic under discussion. The review also discusses the different strategies which are substantiated in recent times to expand the utilisation of hydrogels. The primary intent of this review is to render a comprehensive understanding of hydrogels as an ideal drug delivery system to undergraduates, graduates, biomedical students and researchers across the globe. It also targets to unravel the fundamental, applied and general aspects of hydrogels, offering valuable insights to help individuals associated with multidisciplinary research and application spheres.&#x0D; Keywords: Gelation, Biocompatibility, Cross-linking, Smart hydrogels, Polymerization, Architecture, Polymer network

Reversibility in the Physical Properties of Agarose Gels following an Exchange in Solvent and Non-Solvent.

Agarose forms a homogeneous thermoreversible gel in an aqueous solvent above a critical polymer concentration. Contrary to the prevailing consensus, recent confirmations indicate that agarose gels are also stable in non-solvents like acetone and ethanol. A previous study compared gel characterisations and behaviours in water and ethanol, discussing the gelation mechanism. In the current work, the ethanol gel is exchanged with water to explore the potential reversibility of the displacement of water in agarose. Initially, the structure is characterised using 1H NMR in DMSO-d6 and D2O solvents. Subsequently, a very low yield (0.04) of methyl substitution per agarobiose unit is determined. The different gels after stabilisation are characterised using rheology, and their physical properties are compared based on the solvent used. The bound water molecules, acting as plasticizers in aqueous medium, are likely removed during the exchange process with ethanol, resulting in a stronger and more fragile gel. Next, the gel obtained after the second exchange from ethanol back to water is compared with the initial gel prepared in water. This is the first time where such gel has been characterised without undergoing a phase transition when switching from a good solvent to a non-solvent, and vice versa, thereby testing the reversibility of the solvent exchange. Reversibility of this behaviour is demonstrated through swelling and rheology experiments. This study extends the application of agarose in chromatography and electrophoresis.

Research progress of methylcellulose-based thermosensitive hydrogels applied in biomedical field

Methylcellulose is a semi-flexible cellulose ether derivative, whose hydrogels are thermosensitive and reversible, with good biocompatibility and adjustable function, and its application has attracted much attention in the biomedical field. In this paper, the application of methylcellulose-based thermo-sensitive hydrogels in biomedical field was reviewed. Based on the mechanism of gelation and influencing factors of methylcellulose, this paper focused on the recent advances in biomedical applications of methylcellulose-based hydrogels, including drug delivery, regenerative medicine, and other related fields. The current achievements in these fields were summarized in the form of lists in this paper to provide ideas and tendencies for future research. Finally, the future development of multifunctional methylcellulose-based hydrogel materials with improved performance was also discussed.