Preparation Of Hydrogels Research Articles

‘Click’ hydrogels from renewable polysaccharide resources: Bioorthogonal chemistry for the preparation of alginate, cellulose and other plant-based networks with biomedical applications

Click chemistry refers to a class of highly selective reactions that occur in one pot, are not disturbed by water or oxygen, proceed quickly to high yield and generate only inoffensive byproducts. Since its first definition by Barry Sharpless in 2001, click chemistry has increasingly been used for the preparation of hydrogels, which are water-swollen polymer networks with numerous biomedical applications. Polysaccharides, which can be obtained from renewable resources including plants, have drawn growing attention for use in hydrogels due to the recent focus on the development of a sustainable society and the reduction of the environmental impact of the chemical industry. Importantly, plant-based polysaccharides are often bioresorbable and exhibit excellent biocompatibility and biomimicry. This comprehensive review describes the synthesis, characterization and biomedical applications of hydrogels which combine the renewable and biocompatible aspects of polysaccharides with the chemically and biomedically favorable characteristics of click crosslinking. The manuscript focuses on click hydrogels prepared from alginate and cellulose, the most widely used polysaccharides for this type of hydrogel, but also click hydrogels based on other plant-derived polymers (e.g. pectin) are discussed. In addition, the challenges are described that should be overcome to facilitate translation from academia to the clinic.

Assessment of chitosan-PVA hydrogels infused with marine collagen peptides for potential wound healing applications

Ideal wound dressings should show enhanced moisture management at the wound site, antibacterial and physical barrier, and mechanical robustness. Additionally, it should be easy to apply to the wound and be biocompatible and non-toxic. In this study, a linker-free freeze-thaw procedure was used to create an array of chitosan/PVA hydrogels blended with commercially available marine collagen peptides. Marine collagen peptides (CP) are easily available as by-products of the marine food industry and are an inexpensive and novel source of biomaterial in this field. The different weight ratios of chitosan, PVA, and CP influenced the hydrogel properties such as swelling, gel content, evaporation, and mechanical properties. Furthermore, SEM and ATR-FTIR were used to characterize the hydrogels generated under ideal conditions. After 24 h, the optimum hydrogel (chitosan:PVA:CP ratio of 1:5:1) showed a water absorption capacity of up to 900 %, a gel content of 80 %, and a 40 % evaporation rate. The physical interactions between marine collagen peptide and gel-forming components were validated by ATR-FTIR spectra, and the hydrogel kept a sufficient porous structure for potential wound dressing application. To test the mechanical integrity of the hydrogels, compression testing was carried out showing a compressive modulus of up to ∼40 kPa. The addition of marine collagen peptide in the chitosan/PVA hydrogel increased its wettability, antimicrobial capabilities, and hemostatic properties. Furthermore, the hydrogel preparation procedure is simple and does not use toxic chemicals, serving as a model for developing safe and effective hydrogel wound dressing.

POLYMER BIOCOMPOSITES IN THE FORM OF HYDROGEL USED FOR THE TREATMENT OF PRESSURE SORES

This paper presents research related to the development of hydrogel polymer biocomposites (chitosan and alginate) with an analgesic medication (lidocaine hydrochloride). The pharmaceutical availability of lidocaine hydrochloride from the hydrogel preparations was evaluated for transdermal systems in accordance with the Polish Pharmacopoeia, XI Edition. The rheological tests showed that these preparations had the characteristics of non-Newtonian, pseudoplastic liquids, for which the viscosity decreases as the shear rate increases. The developed hydrogel preparations showed bacteriostatic and bactericidal effects against both Escherichia coli and Staphylococcus aureus. The release of lidocaine hydrochloride from the tested hydrogel was a complex process that followed first-order kinetics. The rate of release could be influenced by appropriate selection of the composition of the biocomposite.

Preparation and characterization of smart hydrogels (magnetic field responsive)

Iron nanoparticles were prepared by using the co-precipitation process, and then used to fabricate magnetic field-responsive hydrogel films. The magnetic nanoparticles' structural, physical-chemical, morphological, and magnetic characteristics and the effect of hydrogel films' coating concentration were studied. The properties of the hydrogel film responsive to the magnetic field were investigated using Fourier analysis spectroscopy infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and a vibration sample magnetometer (VSM). The results indicated that all samples showed good inter-integration of the constituent materials and their functional groups. The hydrogel film samples which were polycrystalline, had broad diffraction peaks and showed constant particle size with nearly spherical particles with rounded edges. The SEM image of the magnetic nanoparticles with and without coating was established for the accumulation of numerous nanoparticles with a 17 nm mean diameter. In addition, the magnetic properties of the magnetic field-sensitive hydrogel films were evident and sufficient for drug delivery to the desired location.

Formulation and Characteristics of Film Forming Hydrogel (FFH) of Yellow Root Extract (Arcangelisia Flava (L.) Merr.) As Wound Healing for Burns

The aim of this study was to determine the effect of different concentrations of yellow root extract (Arcangelisia Flava (L.) Merr.) and film-forming hydrogel (FFH) polymer on the physicochemical characteristics and stability of the preparation. The method for making FFH is carried out using varying concentrations (%) of 0,5 extract, 1, and 1,5, as well as variations in concentration (%) of PVP and PVA (2,8:15,2; 2,8:17,2; 2,8:19,2). F1 – F9 were evaluated for physicochemical characteristics, including organoleptic, pH, spreadability, adhesive power, drying time, viscosity, stickiness, and mechanical properties. Next, freeze-thaw stability and data analysis were carried out using the LSD test at a confidence level of 95%. This research indicates that the FFH formulation of yellow root extract has good characteristics in the F1 formula with an extract concentration of 0.5% and a concentration (%) of PVP and PVP polymer (2.8:15.2), which meets all physicochemical characteristic tests. The results of data analysis using SPSS showed that the extract concentration and polymer concentration had a significant effect (0.05<0.05) on the characteristics and stability of the Yellow Root Extract Film Forming Hydrogel (FFH) preparation.

Microwave-Assisted Synthesis of Corn Husk-Based Hydrogels Grafted with Acrylamide

Corn husk waste contains cellulose, which has the potential as a raw material for hydrogel preparation. Hydrogels can be applied as water purification, diapers, and superabsorbents. This study aimed to synthesize hydrogel from corn husk cellulose grafted with acrylamide monomer using a microwave-assisted grafting method. Potassium peroxodisulfate (PPD) was used as an initiator, and the effects of acrylamide and PPD on hydrogel swelling capacity were investigated. The process involved drying and crushing corn husks into powder, then mixing the powder with acrylamide and PPD for microwave grafting to form a polymer, which was then ground into powder. The grafted polymer was combined with carrageenan to create bead gels soaked in distilled water and urea to measure swelling capacity. Results showed that swelling capacity increased with more acrylamide and decreased with more PPD. The highest swelling capacity reached 1016.16% in water and 961.6% in urea. FTIR analysis confirmed the successful grafting of acrylamide onto corn husk cellulose by detecting changes in the infrared spectrum. Based on FTIR and swelling capacity data, it was concluded that the grafting process was completed using the microwave method with PPD as the initiator.

Self-Polymerized Tough and High-Entanglement Zwitterionic Functional Hydrogels.

Zwitterionic hydrogels exhibit great potential in biomedical applications due to their antifouling properties and biocompatibility. However, the single-network structure of pure zwitterionic hydrogels leads to a low toughness and strength, limiting their application in biomedical fields. In this work, a high entanglement sulfobetaine methacrylate-dopamine hydrogel (SBMA-DA-PE) with low cross-linker content and high monomer concentration is prepared by using a dopamine oxidative radical polymerization method. Compared to a regular zwitterionic hydrogel, the SBMA-DA-PE hydrogel exhibits a 5-fold increase in tensile fracture stress and a 10-fold increase in compressive fracture stress. The SBMA-DA-PE hydrogel possesses excellent mechanical properties (the maximum compressive stress ≥4.85MPa, the maximum compressive strain ≥90%). Besides, the non-covalent interactions between catechol or ortho-quinones within the SBMA-DA-PE hydrogel, combined with strong intermolecular electrostatic interactions, endow the SBMA-DA-PE hydrogel with great self-healing capabilities and fatigue resistance. The SBMA-DA-PE hydrogel demonstrates low swellability and possesses good antifouling properties. Furthermore, the good printability and conductivity of the tough SBMA-DA-PE hydrogel endows it with new possibilities for developing biological 3D scaffolds and electronic devices. Overall, this work provides new insights into the preparation of zwitterionic hydrogels with high mechanical strength and multi-functionality for biomedical applications.

Preparation of photo-crosslinked microalgae-carboxymethyl chitosan composite hydrogels for enhanced wound healing

Integrating microalgae into wound dressings has proven effective in promoting chronic wound healing through photosynthesis-induced oxygen release. However, challenges such as high crosslinking temperatures and prolonged gel molding processes limit microalgae growth and reduce the overall therapeutic impact. In this work, inspired by cell-symbiotic photo-crosslinked hydrogels, we present a novel photo-crosslinked microalgae carboxymethyl chitosan composite hydrogel. This hydrogel completes crosslinking at room temperature within 30 s, enhancing chronic wound healing. The composite gel incorporates photosynthesizing unicellular microalgae (Chlamydomonas reinhardtii) and the antimicrobial agent ciprofloxacin during preparation. In light, the gel continues to photosynthesize, releasing oxygen while simultaneously acting as an antibacterial agent. This dual action results in the upregulation of CD31 and VEGFA levels and the downregulation of HIF-1α levels in diabetic wounds. The wound closure rate reached approximately 96.70 % on day 12 in the composite gel group, compared to only 78.98 % in the control group. Therefore, the composite gel promotes healing by reducing local hypoxia, encouraging angiogenesis, and lowering infection risk. These results suggest that photo-crosslinked microalgae composite gels provide an effective strategy for localized oxygen delivery to promote wound healing and offer a viable method for rapidly preparing living biomaterials under suitable conditions.

Preparation of double network antibacterial hydrogel modified by hydroxamic acid gelatin/polyacrylamide and high efficiency uranium extraction from seawater

Uranium extracted from seawater can solve the problem of the shortage of uranium on land and provide potential resources for the nuclear power industry. However, the high salinity and low uranium concentration in seawater, coupled with the presence of competing ions and bacteria, pose significant challenges to this technology. In this study, a hydroxyl oxime acid modified gelatin/polyacrylamide double network (Gel/PAM(DN)-HA) hydrogel developed for efficient uranium extraction from seawater. The adsorption capacity of Gel/PAM(DN)-HA hydrogel for uranium in 15 ppm uranium solution was as high as 397.04 mg-U/g-Ads, with a reuse rate of 78.46 % ± 5.84 % after 5 cycles of adsorption-desorption. Gel/PAM(DN)-HA was immersed in natural seawater for 24 days to evaluate its adsorption capacity. Gel/PAM(DN)-HA demonstrated an impressive uranium extraction capacity of 4.801 mg·g−1. Antibacterial experiments demonstrated that Gel/PAM(DN)-HA can effectively inhibit the Escherichia coli (E. coli ATCC25922) and Staphylococcus aureus (S. aureus ATCC6538). The results highlight the adsorbent's significant potential for extensive utilization in extracting uranium from seawater.

Preparation of injectable self-healing hydrogels using carboxymethyl chitosan and oxidized dextran with incorporating quercetin-loaded PF127 micelles for wound healing

Rapid achievement of the irregularly shaped post-wound closure is closely related to the effectiveness of clinical hydrogel-based wound dressings to inhibit microbial invasion and promote wound healing. Herein, an injectable and self-healing hydrogel with rapid gelation was engineered based on carboxymethyl chitosan (CMCS) and oxidized dextran (Odex). The hydrophobic drug, quercetin, with antioxidant and antibacterial effects, was loaded in the PF127 micelles with an encapsulation efficiency of 59.06 %, and then quercetin-loaded PF127 micelles were ingeniously incorporated into the hydrogels. The prepared composite hydrogels not only showed a stable and sustained release behavior of quercetin, but also possessed excellent antioxidant activities and antibacterial properties against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Moreover, the composite hydrogels with microstructure (150–250 μm) also exhibited self-healing and injectable properties. In addition, the survival rates of NIH 3T3 cells when cultured with hydrogel extract were all over 80 %, illustrating the excellent biocompatibility of hydrogels. Therefore, our prepared multifunctional composite hydrogels showed a broad prospect as wound dressings for treating acute skin injuries.

Plasma‐Assisted Preparation and Properties of Chitosan‐Based Magnetic Hydrogels

Chitosan‐based magnetic hydrogel has become a research hotspot in the field of material science due to the driven deformation or movement under the action of magnetic field. The unique properties make it show great application potential in medicine, biosensing, environmental protection, and other fields. Herein, the chitosan‐based nanomagnetic composite hydrogels are prepared by plasma assistance. The surface morphology, infrared spectra, mechanical properties, swelling ratio, water absorption, porosity, and degradation of the prepared hydrogels are investigated. The results prove the superiority of plasma‐assisted preparation of magnetic chitosan hydrogels and provide a new method for the design of smart hydrogels.

Preparation of sulfated arabinogalactan-loaded hydrogel for wound healing in mouse burn model

Sulfation of polysaccharides can affect their biological activity by introducing sulfate groups. Skin burns occur regularly and have a great impact on normal survival. In this study, sulfated arabinogalactan (SAG) was prepared by sulfation, and polyvinyl alcohol (PVA) was used to prepare hydrogels for the treatment of scalded skin in mouse. The results show that the main chain of SAG consists of →3-β-D-Galactose (Gal)-(1, →3, 6)-β-D-Gal-(1 and →4)-β-d-Glucose (Glc)-(1. The chain is a neutral polysaccharide composed of T-β-L-Arabinose (Araf)-(1→, with a molecular weight of 17.9 kDa. At the same time, PVA + SAG hydrogel can promote the scald repair of mouse skin by promoting collagen deposition and angiogenesis, and regulating the TLR4/MyD88/NF-κB signaling pathway. Interestingly, the effect of SAG on promoting the repair of scald wounds is enhanced after AG is derivatized by sulfation. Therefore, the preparation of SAG by sulfation can promote scald repair, and has great application potential in the field of food and medicine.

Synthesis, characterization and application of hydrogel for cancer treatment

The purpose of this review paper is to provide a comprehensive overview of hydrogels in cancer therapy. This aims to explore the definition of hydrogels and their unique characteristics of hydrogel, role of hydrogel in cancer therapy, cancer therapy treatment approaches, challenges in cancer therapy, that make them suitable for use in cancer treatment. It seeks to emphasize on the integration of innovative approaches and new technologies in addressing the challenges of conventional cancer therapies and to highlight their potential to revolutionize cancer treatment approaches. The review will delve into different types of hydrogels, methods of preparation of hydrogel including natural and synthetic hydrogels, providing insights into their characteristics, synthesis methods, and tenability. Furthermore, it will examine the diverse applications of hydrogels in cancer therapy, such as drug delivery systems, tissue engineering, localized therapy, and combination therapies.

Preparation and Stability Study of an Injectable Hydrogel for Artificial Intraocular Lenses.

Currently available intraocular lenses (IOLs) on the market often differ significantly in elastic modulus compared to the natural human lens, which impairs their ability to respond effectively to the tension of the ciliary muscles for focal adjustment after implantation. In this study, we synthesized a polyacrylamide-sodium acrylate hydrogel (PAH) through the cross-linking polymerization of acrylamide and sodium acrylate. This hydrogel possesses excellent biocompatibility and exhibits several favorable properties. Notably, the hydrogel demonstrates high transparency (94%) and a refractive index (1.41 ± 0.07) that closely matches that of the human lens (1.42). Additionally, it shows strong compressive strength (14.00 kPa), good extensibility (1400%), and an appropriate swelling ratio (50 ± 2.5%). Crucially, the tensile modulus of the hydrogel is 2.07 kPa, which closely aligns with the elastic modulus of the human lens (1.70-2.10 kPa), enabling continuous focal adjustment under the tension exerted by the ciliary muscles.

Facile One-Pot Preparation of Polypyrrole-Incorporated Conductive Hydrogels for Human Motion Sensing.

Conductive hydrogels have been widely used in soft robotics, as well as skin-attached and implantable bioelectronic devices. Among the candidates of conductive fillers, conductive polymers have become popular due to their intrinsic conductivity, high biocompatibility, and mechanical flexibility. However, it is still a challenge to construct conductive polymer-incorporated hydrogels with a good performance using a facile method. Herein, we present a simple method for the one-pot preparation of conductive polymer-incorporated hydrogels involving rapid photocuring of the hydrogel template followed by slow in situ polymerization of pyrrole. Due to the use of a milder oxidant, hydrogen peroxide, for polypyrrole synthesis, the photocuring of the hydrogel template and the growing of polypyrrole proceeded in an orderly manner, making it possible to prepare conductive polymer-incorporated hydrogels in one pot. The preparation process is facile and extensible. Moreover, the obtained hydrogels exhibit a series of properties suitable for biomedical strain sensors, including good conductivity (2.49 mS/cm), high stretchability (>200%), and a low Young's modulus (~30 kPa) that is compatible with human skin.

Preparation of Composite Hydrogels Based on Cysteine-Silver Sol and Methylene Blue as Promising Systems for Anticancer Photodynamic Therapy.

In this study, a novel supramolecular composite, "photogels", was synthesized by mixing of cysteine-silver sol (CSS) and methylene blue (MB). A complex of modern physico-chemical methods of analysis such as viscosimetry, UV spectroscopy, dynamic and electrophoretic light scattering, scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that MB molecules are uniformly localized mainly in the space between fibers of the gel-network formed by CSS particles. Molecules of the dye also bind with the surface of CSS particles by non-covalent interactions. This fact is reflected in the appearance of a synergistic anticancer effect of gels against human squamous cell carcinoma even in the absence of light irradiation. A mild toxic influence of hydrogels was observed in normal keratinocyte cells. Photodynamic exposure significantly increased gel activity, and there remained a synergistic effect. The study of free-radical oxidation in cells has shown that gels are not only capable of generating reactive oxygen species, but also have other targets of action. Flow cytometric analysis allowed us to find out that obtained hydrogels caused cell cycle arrest both without irradiation and with light exposure. The obtained gels are of considerable interest both from the point of view of academics and applied science, for example, in the photodynamic therapy of superficial neoplasms.

Effect of potassium salt type on physicochemical properties of carrageenan films and rehydrated hydrogels

This study focused on the effect of potassium salt type on the physicochemical properties of carrageenan (Car) films and rehydrated hydrogels, with the aim of developing a new method for the preparation of Car hydrogels. The addition of potassium salt decreased the tensile strength (TS) of Car films, especially those containing KI. After rehydration, the weight and thickness change ratios of the Car films decreased with salt addition, and the sequence was as follows: K2CO3 < KH2PO4 < CH3COOK < KCl < K2SO4 < KSCN < KI < C6H5K3O7. The effect of potassium salt type on the TS and thermal transition temperature of rehydrated hydrogels was opposite that on weight and thickness change ratios. The hydrogels with K2CO3, KH2PO4, CH3COOK, KCl, and K2SO4 exhibited lower transverse relaxation time (T2) and smaller pore size compared with the other hydrogels. On the other hand, the effect of potassium salt type on hydrogels prepared using Car films soaked in potassium salt solution (S-Car) was similar to that observed on hydrogels prepared using Car films with potassium salt soaked in ultrapure water (U-Car). Compared with U-Car hydrogels, the S-Car hydrogels had higher TS and thermal transition temperature and lower elongation at break, T2, pore size, and hydrogen bond intensity. In conclusion, the potassium salt type and soaking method can be used to regulate the properties of Car hydrogels and provide a theoretical basis for the design of Car hydrogels.

Properties of hydrogel for adsorbent textile dye waste based cellulose-carboxymethyl sago starch

Abstract The use of a single natural polymer in hydrogel preparations is considered insufficient to produce hydrogels that are more durable, more stable, and stronger. Blends of various natural polymers can improve each sago other’s lack of physicochemical characteristics and produce new properties. This research combines two natural polymers, cellulose and starch. Cellulose isolation from Gracilaria verrucosa seaweed using acid hydrolysis and alkaline autoclaving method produced 14.01% cellulose. This study combined the results of cellulose isolation with carboxymethyl sago starch at 0.09; 0.14 and 0.24 mol/mol AGU. The isolated cellulose-carboxymethyl sago starch has the potential as a hydrogel material with the addition of crosslinkers such as epichlorohydrin (ECH). This study aims to synthesize hydrogels from cellulose-carboxymethyl sago starch with application as a textile dye waste absorbent with a concentration of epichlorohydrin (ECH) at 7.5%. Analysis of carboxymethyl sago starch is degrees of substitution, water-soluble index (WSI), and swelling power (SP). The hydrogel properties are characterized by the degree of swelling, degree of polymerization, FTIR, and SEM, and the hydrogel adsorption ability is characterized by adsorption efficiency using a microplate reader. The research results show that hydrogel can be synthesized optimally by adding carboxymethyl sago starch (CMSS) at 0.24 mol/mol AGU. The results of FTIR analysis are also by chemical measurements (swelling and gel fraction). In contrast, for maximum colour absorption, the addition of carboxymethyl sago starch is 0.09 mol/mol AGU for purple, yellow, and black and 0.14 mol/mol AGU for green color absorption. In conclusion, the adsorption ability of hydrogel in commercial textile dyes is maximum when the carboxymethyl sago starch (CMSS) is added at 0.09 mol/mol AGU with the best adsorption efficiency at purple 86.22%, yellow 77.40%, black 73.70% and at the addition of CMSS 0.14 mol/mol AGU the best adsorption efficiency in green is 73.46%.

Thermoelectric hydrogels for self-powered wearable biosensing

Although the flourishing of the Internet of Things and artificial intelligence has accelerated the development of wearable smart bioelectronics, heavy reliance on external power remains a problem that needs to be solved. Thermoelectric materials have emerged as a promising solution, efficiently converting body heat into electrical energy to provide a stable and unrestricted power supply for wearables. Moreover, in the field of wearable thermoelectric biosensing, where flexibility is highly demanded, hydrogels with excellent electrical conductivity, flexibility and biocompatibility through structural and compositional optimization have become ideal materials for constructing biosensors and meet the diverse application needs of wearable bioelectronics. This article systematically reviews the latest research progress on thermoelectric gels for self-powered wearable biosensing, including the principles of thermoelectric operation, as well as the preparation, design, and application of thermoelectric hydrogels. The current state of thermoelectric gel-based wearable applications in the fields of temperature sensing, strain sensing, temperature-strain synergistic sensing, respiratory monitoring, and sweat analysis are displayed in the article. Finally, the paper summarizes the current challenges and prospects of thermoelectric gels in self-powered wearable bioelectronics, encouraging the rapid application and realization of thermoelectric gel-based smart wearables.

Recent Advances in Superabsorbent Hydrogels Derived from Agro Waste Materials for Sustainable Agriculture: A Review.

Superabsorbent hydrogels made from agro waste materials have the potential to promote sustainable agriculture and environmental sustainability. These hydrogels not only help reduce water consumption and increase crop yields but also contribute to minimizing waste and lowering greenhouse gas emissions. Recent research on superabsorbent hydrogels derived from agro wastes has focused on the preparation of hydrogels based on natural polymers isolated from agro wastes, such as cellulose, hemicellulose, and lignin. This review provides an in-depth examination of hydrogels developed from raw agro waste materials and natural polymers extracted from agro wastes, highlighting that these studies start with raw wastes as the main materials. The utilization strategies for specific types of agro wastes are comprehensively described. This review outlines different methods utilized in the production of these hydrogels, including physical cross-linking techniques such as dissolution-regeneration and freeze-thawing, as well as chemical cross-linking methods involving various cross-linking agents and graft polymerization techniques such as free radical polymerization, microwave-assisted polymerization, and γ radiation graft polymerization. Specifically, this review explores the applications of agro waste-based superabsorbent hydrogels in enhancing soil properties such as water retention and slow-release of fertilizers for sustainable agriculture.