Preparation Of Hydrogels Research Articles

Blended ƙ-carrageenan and xanthan gum hydrogel containing ketoprofen-loaded nanoemulsions: Design, characterization, and evaluation in an animal model of rheumatoid arthritis.

This study reports the preparation of hydrogels (HG) made with xanthan gum (XG) and ƙ-carrageenan (KC) polysaccharides containing ketoprofen (KET)-loaded nanoemulsions (NK) and their evaluation in a rheumatoid arthritis (RA) model. The nano-based HGs exhibited nanometric-sized droplets (~ 100nm), an acidic pH (5.10-6.83), drug content above 85%, a suitable spreadability factor, and pseudoplastic flow behavior. The most promising blend (HGCX 2:1) demonstrated sustained KET release, reaching 81.44 ± 6.11% after 5h, and superior drug concentration in the skin layers (237.91 ± 41.0µg/g). The formulation was selected due to its enhanced bioadhesiveness, with the HG-NK formulation showing the highest bioadhesion force and occlusion factor. RA was induced by complete Freund's adjuvant (CFA) intraplantar injection into the left hind paw of male and female Swiss mice. Treatments with HGs were applied to the animals' dorsal region for 7days. Notably, HG-NK demonstrated remarkable efficacy, reversing mechanical sensitivity in male mice and significantly reducing thermal sensitivity in both genders. Moreover, HG-NK provided a significant reduction in paw edema (52-fold in males, 27-fold in females) and inflammatory markers, such as myeloperoxidase activity (32-fold in males, 14-fold in females) and lipid peroxidation (2.5-fold in males, twofold in females). The formulation also promoted greater permeation of KET across the skin. These findings underscore the significant reduction in inflammatory markers by the HG-NK formulation, highlighting its potent anti-inflammatory effects and potential as a promising therapeutic strategy for managing RA.

Preparation of Calcium Alginate-Based Hydrogels with Precisely Designed Centrosymmetric Geometries for Efficient Water Evaporation in Response to Different Solar Incidence Angles.

Hydrogels are popular materials for desalination and can significantly reduce the vaporization enthalpy of water; however, there are few reports on hydrogels with a controllable multilevel structural design for water evaporation. Herein, a calcium alginate and traditional Chinese ink-based evaporator (CIE) are proposed and fabricated using directed freezing technology to construct radial channels, followed by freeze-drying and physical cross-linking. Because of the squeezing of ice crystals and the shaping effect of the PDMS template, the prepared evaporator exhibits a sea-urchin-shaped highly geometrical centrosymmetric structure with numerous multilevel pore channels, which promotes the rapid transport of water under different solar incidence angles as the sun rotates as well as overcomes the structural shrinkage of the hydrogel caused by insufficient water supply. Additionally, the radial channels in the spherical hydrogel overcome the traditional limitation of saltwater being continuously concentrated in the same area where the evaporation rate is the highest. As a result, the urchin-structured CIE exhibits a water evaporation rate of 3.52 kg m-2 h-1 at 1 sun irradiation, which is 45.5% higher than that of the unpatterned CIE. This multilevel structural design provides a strategy for the fabrication of an all-day water hydrogel-based evaporator without structural shrinkage under solar irradiation.

Biocomposite Polyvinyl Alcohol/Ferritin Hydrogels with Enhanced Stretchability and Conductivity for Flexible Strain Sensors

Protein-based hydrogels with stretchability and conductivity have potential applications in wearable electronic devices. However, the development of protein-based biocomposite hydrogels is still limited. In this work, we used natural ferritin to develop a PVA/ferritin biocomposite hydrogel by a repetitive freeze–thaw method. In this biocomposite hydrogel, ferritin, as a nano spring, forms a hydrogen bond with the PVA networks, which reduces the crystallinity of PVA and significantly improves the stretchability of the hydrogel. The fracture strain of the PVA/ferritin hydrogel is 203%, and the fracture stress is 112.2 kPa. The fracture toughness of the PVA/ferritin hydrogel is significantly enhanced to 147.03 kJ/m3, more than 3 times that of the PVA hydrogel (39.17 kJ/m3). In addition, the free residues and iron ions of ferritin endow the biocomposite hydrogel with enhanced ionic conductivity (0.15 S/m). The strain sensor constructed from this hydrogel shows good sensitivity (gauge factor = 1.7 at 150% strain), accurate real-time resistance response, and good long cyclic working stability when used for joint motion monitoring. The results indicate that a PVA/ferritin biocomposite hydrogel prepared by a facile method has enhanced stretchability and conductivity for flexible strain sensors. This work develops a new method for the preparation of protein-based hydrogels for wearable electronic devices.

Fast fabrication of stimuli-responsive MXene-based hydrogels for high-performance actuators with simultaneous actuation and self-sensing capability.

Poly(N-isopropylacrylamide) (PNIPAM) composite hydrogels have recently emerged as promising candidates for soft hydrogel actuators. However, developing a facile and fast method to obtain multifunctional PNIPAM hydrogel actuators with simulating biological versatility remains a major challenge. Herein, we developed a fast-redox initiation system to prepare PNIPAM/sodium carboxymethyl cellulose (CMC)/T3C2Tx MXene nanocomposite hydrogel with multidirectional actuating behaviors and improved mechanical properties. The rapid thermoresponsive behavior of the PNIPAM/CMC/MXene layer bestows its corresponding bilayer actuator with an extraordinary actuation speed of 9.36°/s in hot water. Owing to the high photothermal conversion of MXenes, this PNIPAM/CMC/MXene hydrogel displays a range of remote-controlled actuations upon NIR light irradiation, including bending, rolling, displacement, and simulations of the sea eel's hunting behaviors in a water environment. More importantly, based on the excellent electrical properties of MXene, the PNIPAM/CMC/MXene-based hydrogel actuators have accomplished a self-sensing function by integrating the surface temperature-bending angle-the relative resistance changes during the NIR light-driven actuation process. The photothermal actuator's integrated actuation and sensing capabilities have facilitated the feedback of the contact and movement dynamics of the bioinspired artificial tongue. The straightforward preparation and multifunctional design of MXene-based hydrogel may facilitate the development of soft smart actuators.

Study on Highly Sensitive Capacitive Pressure Sensor Based on Silk Fibroin-Lignin Nanoparticles Hydrogel.

Silk fibroin (SF) hydrogel has been proven to have excellent applications in the field of pressure sensors, but its sensing performance still needs improvement. A flexible hydrogel prepared from natural macromolecular materials was developed, and lignin nanoparticles (LNPs) were introduced during the preparation of the SF hydrogel. When LNPs account for 3% of SF, the sensing unit of the SF-LNPs3% hydrogel exhibits high stress sensitivity (1.32 kPa-1), fast response speed (<0.1 s), and superior cycle stability (≥8000 cycles). The sensor can detect human motion information, such as finger bending, elbow bending, and pulse signals. When worn at the vocal cord position, it can detect the peak value of the characteristic signal during the wearer speaks. This work demonstrates that the SF-LNPs3% hydrogel has high sensitivity and shows great potential in the field of pressure sensors.

Tough, highly conductive and frost-resistant chitosan based hydrogel for flexible sensor.

Conductive hydrogels with exceptional mechanical properties have received extensive attention in flexible strain sensors. However, there is still a huge challenge in the preparation of hydrogels with high toughness, conductivity and frost resistance performance. In this study, the prepared PA-PAAM-CS (PPAC) composite hydrogels were obtained by incorporating phytic acid (PA) and chitosan (CS) into poly(acrylamide-co-stearyl methacrylate) (PAAM) polymer network. The as-prepared PPAC composite hydrogel has exhibited good mechanical properties, good electrical conductivity, frost resistance and good strain sensitivity. The flexible strain sensor assembled by the fabricated PPAC hydrogel can be used to detect human motion, including small and huge human motion, showing good sensitivity and stability in a wide temperature range. Meanwhile, the hydrogels based pressure sensors as writing board have exhibited good sensitivity to tiny changes in writing various letters. Therefore, the prepared hydrogel will have broad application prospects in wearable devices, electronic skin and multifunctional sensor components.

Preparation of 4D hydrogels with PET-RAFT and orthogonal photo-reactions

We investigated of 4D dimensional hydrogels with photo orthogonal reaction. The 4D movements were observed and discussed based on the physical properties and computer simulation.

Cascaded MXene/Metal-Organic framework system enables rapid gelation of ultrastretchable and high-toughness conductive hydrogels for multifunctional wearable electronics

Flexible conductive hydrogels have emerged as promising materials for the fabrication of advanced wearable electronics. Although various crosslinking strategies and functional materials have been introduced to prepare hydrogels with high resilience, conformal adhesion and fatigue resistance, the rapid, facile and energy-free gelation of conductive hydrogels with excellent mechanical strength remains a critical challenge. Herein, a facile and universal strategy for the rapid gelation of hydrogels is proposed via constructing a cascade catalytic system comprising MXene and Fe-MIL-88NH2 metal–organic framework to accelerate the gelation process through their synergistic enhancement effect. The cascade system not only initiates the gelation of hydrophilic monomers within 101 s, but also functions as the cross-linker and conductive filler to form a multibond network and multiple conductive pathways with oxidized sodium alginate (OSA) and Ca2+, which significantly improves the mechanical and electrical performance of the hydrogels, including high stretchability (2200 %), toughness (1.15 MJ/m−3(−|-)), tunable adhesion, stability, excellent fatigue resistance (1500 cycles) and superior conductivity (3.51 S m−1). With high strain sensitivity (gauge factor = 9.51) and low detection limit, hydrogel-based wearable sensors are capable of accurately and consistently monitoring of the movements and electrophysiological signals from the human body. By harmonizing the preparation and performance of hydrogels, this universal strategy sheds new light on the construction of next-generation of advanced wearable electronics.

Design and electrospinning synthesis of red luminescent-highly anisotropic conductive Janus nanobelt hydrogel array films

A new strategy for the preparation of conductive hydrogels by a simple method with high anisotropic conductivity is proposed.

Carboxymethylated yeast β-glucan: Biological activity screening in zebrafish, sprayable hydrogel preparation, and wound healing study in diabetic mice

Yeast β-glucan exhibits dramatic potential as wound healing regent owing to its various biological properties including immunomodulatory, anti-inflammatory, and antioxidant. But, the poor water solubility of yeast β-glucan limits its application. In this study, some carboxymethylated yeast β-glucans (CMGs) with different substitution degree was prepared. The effect of substitution degree on biological activities of carboxymethylated yeast β-glucan was investigated using zebrafish model. CMG3 with substitution degree 0.55 showed anti-inflammatory, antioxidant, and immunomodulatory activities in zebrafish. CMG3 also showed potential ability to promote angiogenesis and caudal fin regeneration. The cytotoxicity of CMG3 was investigated on L929 cells and the effect of CMG3 on cell migration was studied by scratch test. The hemolysis ratio of CMG3 was determined, and the in vitro antioxidant activity was studied. Next, CMG3 was used to prepare a sprayable hydrogel through a simple method, and the wound healing ability was studied using a streptozotocin-induced diabetic mice model. The results indicated that CMG3-based sprayable hydrogel could accelerate wound healing in a diabetic mice and influence the expression of biomarkers related to inflammatory, macrophage polarization, and angiogenesis.

Alginate-Based Hydrogels with Amniotic Membrane Stem Cells for Wound Dressing Application.

Chronic wounds are a common clinical problem that necessitate the exploration of novel regenerative therapies. We report a method to investigate the in vitro wound healing capacity of an innovative biomaterial, which is based on amniotic membrane-derived stem cells (AMSCs) embedded in an alginate hydrogel matrix. The aim of this study was to prepare an sodium alginate-based hydrogel, cross-linked calcium chloride (CaCl2) with the active ingredient AMSC (AMSC/Alg-H) and to evaluate its in vitro effectiveness for wound closure. This hydrogel preparation involved combining sterile solutions of AMSC, sodium alginate, and CaCl2, followed by rinsing with serum-free media. The cells were cultured in different 6-well plates, namely sodium alginate, calcium chloride, AMSC, Alg-H, and AMSC/Alg-H, in complete medium with 10% FBS. The hydrogel was successfully formulated, as confirmed by characterization techniques including Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), Cytotoxicity Studies, TGF-β1 Level Measurement by ELISA, and Cell Scratch Wound Assay. Cryo-EM characterization of the Alg-H preparation successfully demonstrated the encapsulation of MSCs. FTIR and DSC analyses indicate that crosslinking transpires in Alg-H encapsulating AMSC. The AMSC/Alg-H preparation showed no significant difference in toxicity compared to HaCaT cells (p < 0.05), indicating it was not toxic to HaCaT cells. Furthermore, in the scratch wound assay test at 24hours, the AMSC/Alg-H preparation achieved 100% wound closure, outperforming both AMSC and Alg-H alone. In vitro assessment revealed that AMSC/Alg-H significantly enhanced key wound healing processes, including cell proliferation and migration, compared to Alg-H. Our study demonstrated the promising potential of AMSC/Alg-H as an enhanced regenerative therapy for in vitro wound healing. AMSC/Alg-H was able to maintain the viability of AMSCs and facilitate the formation of tissue-like structures.

Silica hydrogels as a carbon-free solid media for the culture of diverse organisms.

Bacteriological agar plates are commonly used to carry out experiments for the selective growth of microorganisms and the isolation of single-strain colonies. However, the presence of agar itself may be a confounding factor since it may serve as a source of carbon and energy. Moreover, there have been ongoing constraints on the production and sourcing of agar. These concerns have led to an interest in the development of agar substitutes. Silica hydrogels are entirely inorganic carbon-free polymeric materials that lack any source of micronutrients. Herein, a revised method for the preparation of silica hydrogels as a solid culture medium is reported. These gels can be formulated with a range of nutrient-rich or minimal media supplemented with various carbon sources, and can be manipulated in the same manner as agar gels. Their use for the culture and isolation of diverse microorganisms, including both Gram-positive and Gram-negative bacteria, yeast, and filamentous fungi is demonstrated. These silica hydrogels supplemented with either antibiotics or other molecules of interest can also be used for microbial selection experiments.

Molecular mechanisms of the geroprotective action of magnesium hyaluronan in inflamaging human skin fibroblasts

Introduction. The study of the molecular mechanisms of skin aging is one of the key problems of dermatocosmetology. Inflamaging is a chronic low–level inflammation that occurs with age. This condition is characterized by a change in the expression of proteins involved in the processes of aging and skin regeneration. Hyaluronic acid preparations containing metals have shown their geroprotective effect in the conditions of inflamaging. The aim of the studyto identify key biomarkers of cell aging (the development of inflamaging), as well as to study the effect of a hyaluronic acid-based drug with the presence of magnesium in chelated form (Magniderm-09) on human skin fibroblasts in an inflamaging model to assess its possible geroprotective effect. Material and methods. The study was performed on a culture of skin fibroblasts in a model of inflamaging induced by genotoxic stress. To assess the expression of molecular markers, immunohistochemical analysis of levels of Ki-67, collagen I, III and IV, LOX, ubiquitin, CCN1, IL-8, MMP-3, NF-kB, SIRT1, CD44 was performed. Results. The modeling of inflamaging revealed a decrease in the expression of Ki-67, all types of collagen, LOX, CCN1, SIRT1, CD44, as well as an increase in proinflammatory cytokines – IL-8, NF-kB, MMP-3 and ubiquitin. Administration of the drug "Magniderm-09" returned expression levels to normal values, which indicates its geroprotective effect. Conclusion. A correlation has been revealed between the chemical composition of a hyaluronic acid-based hydrogel preparation with the presence of magnesium in chelated form and the molecular biological changes accompanying the process of cellular aging.

Characterization of Biopolymer Hydrogels Prepared with Water Exposed to Indirect Plasma Treatment.

This study aimed to evaluate the influence of indirect-plasma-treated water (IPTW) in the preparation of hydrogels. Three commonly used natural, biodegradable polymers with the ability to form gels were selected: gelatin, carrageenan, and sodium alginate. The pH, gelling temperature, texture profile, swelling degree, and color of hydrogels were evaluated, and the polymers were subjected to Fourier-transform infrared (FTIR) spectroscopy. The morphology of the hydrogels was investigated using Scanning Electron Microscopy (SEM). Additionally, the physiochemical properties of the water media, which were distilled water (DW) and IPTW, were analyzed. The results indicated that the gels prepared using IPTW were characterized by a lower pH, higher hardness and lower gelation temperature. After 48 h of swelling ratio (SR) testing, gelatin and alginate hydrogels made with IPTW were characterized by lower SR, while an inverse relationship was found in the case of SR of carrageenan gels. The FTIR analysis confirmed changes in the water binding ability. The use of IPTW also significantly affected the microstructure of the tested materials. A statistically significant change in the color of IPTW gel samples was also noted. The results showed that IPTW induces physicochemical changes in hydrogels, which can lead to the enhancement of their practical applications.

Crystalline‐Constrain Enables Preparation of Hierarchical Porous Hydrogels with High Porosity and Good Mechanics

Crystalline‐Constrain Enables Preparation of Hierarchical Porous Hydrogels with High Porosity and Good Mechanics

Electroconductive Nanocellulose, a Versatile Hydrogel Platform: From Preparation to Biomedical Engineering Applications.

Nanocelluloses have garnered significant attention recently in the attempt to create sustainable, improved functional materials. Nanocellulose possesses wide varieties, including rod-shaped crystalline cellulose nanocrystals and elongated cellulose nanofibers, also known as microfibrillated cellulose. In recent times, nanocellulose has sparked research into a wide range of biomedical applications, which vary from developing 3D printed hydrogel to preparing structures with tunable characteristics. Owing to its multifunctional properties, different categories of nanocellulose, such as cellulose nanocrystals, cellulose nanofibers, and bacterial nanocellulose, as well as their unique properties are discussed here. Here, different methods of nanocellulose-based hydrogel preparation are covered, which include 3D printing and crosslinking methods. Subsequently, advanced nanocellulose-hydrogels addressing conductivity, shape memory, adhesion, and structural color are highlighted. Finally, the application of nanocellulose-based hydrogel in biomedical applications is explored here. In summary, numerous perspectives on novel approaches based on nanocellulose-based research are presented here.

Fast-Swelling Tamarind Xyloglucan/PVA Hydrogels with Interconnected Macroporous Structures for Biomedical Applications.

This work demonstrates the preparation of fast-swelling hydrogels based on poly(vinyl alcohol) (PVA) and tamarind xyloglucan (XG), utilizing freeze-drying to achieve an interconnected macroporous structure. Although XG is non-toxic and abundant, it has poor mechanical properties. Therefore, XG was mixed with PVA and crosslinked with citric acid (CA). Without XG, the crosslinked PVA sample contained partially aligned channels several hundred microns wide. The addition of XG (25% w/w) reduced the structural order of the hydrogels. However, the addition of XG improved the swelling ratio from 308 ± 19% in crosslinked PVA to 533.33% in crosslinked PVA/XG. XG also increased the porosity, as the porosity of the crosslinked PVA, XG, and PVA/XG samples was 56.09 ± 2.79%, 68.99 ± 2.06%, and 66.49 ± 1.62%, respectively. Resistance to compression was decreased by the incorporation of XG but was increased by CA crosslinking. The determination of the gel fraction revealed that CA crosslinking was more effective for the PVA component than the XG component. The swelling of all hydrogels was very rapid, reaching equilibrium within 10 s, due to the interconnected macroporous structure that allowed for capillary action. In conclusion, the prepared hydrogels are non-cytotoxic and well suited for biomedical applications such as drug delivery, wound dressings, and hygienic products.

Preparation and Properties of the Sodium Hyaluronate Composite Hydrogel for Medical Cosmetology.

As society advances, an increasing number of people are focusing on the antiaging process of the body and seeking ways to maintain youthful facial features. Intradermal injection has been used to effectively improve the rough and wrinkled skin, playing a role in skin rejuvenation. However, the main component of intradermal injection products is cross-linked sodium hyaluronate (SHA), which has biological toxicity and potential carcinogenicity. In this study, amino acids were used as hyaluronidase inhibitors and combined with non-cross-linked SHA to prepare a synergically stable SHA composite hydrogel. The effects of amino acids on the viscosity and enzyme activity of the hydrogel were investigated. To determine the stability and antioxidant properties of the composite hydrogel, the effects of the introduction of stabilizer and antioxidant on the hydrogel properties were systematically studied. The results of the in vitro study showed that the introduction of amino acids effectively reduced the activity of hyaluronidase, addressing the problem of rapid hydrolysis and the short half-life of SHA hydrogel invivo. In addition, the results revealed that NaCl stabilizer, niacinamide, and vitamin B12 antioxidants effectively maintained the stability and antioxidant properties of the hydrogels. In vivo results showed that SHA composite hydrogels had no irritating effect on the skin, and the subcutaneous experiments of mice showed that SHA composite hydrogel still retained a high content after 4 weeks. Therefore, the SHA composite hydrogels have promising applications in the field of medical cosmetology.

Preparation of Electrochromic Hydrogels Based on Anderson-Type POMs-Viologen Compounds with Photochromic and Thermochromic Properties.

Currently, color-changing materials with multiple responses have emerged as a prominent research focus. In this work, two Anderson-type POMs-viologen compounds were successfully synthesized under solvothermal conditions, namely, (1,3-bcby)·[AlMo6(OH)6O18]·(en)0.5·H2O (1) and (1,3-bcby)·[Co2(H2O)6TeMo6O24]·2H2O (2) (1,3-bcby = 1,1'-bis(3-cyanobenzyl)-4,4'-bipyridine dichloride, en = ethylenediamine). Compound 1 shows a two-dimensional supramolecular lattice structure through the hydrogen bonding of dissociated water molecules. In compound 2, by utilizing the connection of Co atoms, a two-dimensional layered framework is constructed. Owing to the widespread application of viologen compounds in color-changing materials, an investigation was performed for exploration of the photochromic and thermochromic responses of 1 and 2 upon exposure to light and heat. The study reveals that compound 1 exhibits an exceptional reversible photochromic property, while compound 2 demonstrated equally impressive thermochromic behavior. The filter paper prepared by compound 1 was successfully applied to ink-free, erasable printing. Furthermore, ECH-1 and ECH-2 (two types of electrochromic hydrogels), were prepared through varying concentrations of compounds 1 and 2. Notably, ECH-1 exhibits a rapid response time and substantial coloring efficiency. ECH-1 and ECH-2 have been integrated into smart windows, demonstrating their capacity to modulate indoor temperatures effectively.

Preparation of self-healing pHEMA hydrogels using dynamic covalent crosslinkers

Preparation of self-healing pHEMA hydrogels using dynamic covalent crosslinkers