Preparation Of Hydrogels Research Articles

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.

Preparation of hydrogel from the hydroalcoholic root extract of Premna integrifolia L. and its mediated green synthesis of silver nanoparticles for wound healing efficacy

The current investigation concentrated on the fabrication of silver nanoparticles through the root of Premna integrifolia L. The antibacterial and wound healing effects of their silver nanoparticles-hydrogel and root extract-hydrogel were evaluated. The hydroalcoholic root extract of P. integrifolia was enriched with crocetin, ferulic acid, oleanolic acid, oleic acid, syringic acid, and vanillin. The silver nanoparticles were biosynthesized through secondary metabolite-enriched hydroalcoholic root extract (5 %) when mixed with 1 mM AgNO3 and kept under sunlight for 10 minutes. They showed an optimum surface plasmon resonance (SPR) at 447 nm. The aldehyde, phenol, and primary amine groups of the extract reduce silver cations into nanoparticles. The nanoparticles band gap of 2.06 eV showed their semi-conductance behavior. The nanoparticles were spherical, uniformly distributed, and stable. The nanoparticles had a good roughness profile and 57.55 % elemental silver. The silver nanoparticles-hydrogel (10 %) showed an efficient 11±0.11 nm zone of inhibition of S. aureus in comparison to the root extract-hydrogel (10 %), i.e., 9±0.15 nm. The nanoparticles-hydrogel and the root extract-hydrogel did not show noticeable symptoms of acute dermal toxicity. The nanoparticles-hydrogel (10 %) and the root extract-hydrogel (10 %) healed 99.9 % and 97.3 % of the S. aureus- infected wound, respectively. The nanoparticle-hydrogel efficiently induced re-epithelialization in the dermis of S. aureus-infected wound compared to the extract-hydrogel. The nanoparticle-hydrogel enhanced the rate of wound closure.

Photosensitized Reduction and Polymerization for One-Step Preparation of Leucomethylene Blue Hydrogel as a Visual Indicator for Both Gaseous and Dissolved Oxygen.

Oxygen is crucial for many chemical and biological processes, and its facile detection is of great significance in our daily lives. In this study, we report a leucomethylene blue (LMB)-encapsulated hydrogel visual indicator for the detection of both gaseous and dissolved Oxygen (DO). The photosensitization of methylene blue (MB) not only lead to its reduction to colorless LMB but also resulted in hydrogel polymerization, thus allowing the one-step preparation of the LMB-hydrogel. Meanwhile, the photosensitized reduction of MB was quite fast (5000-fold faster than the classical glucose reduction). In this manner, the blue color of MB could be completely decayed within only 1 min. Also, the efficient polymerization triggered by MB photosensitization ensured the rapid preparation of LMB hydrogels within 10 min. By placing the oxygen indicator in air or water, oxygen can specifically oxidize the colorless LMB-hydrogel to the blue MB-hydrogel. When coupled with a smartphone, the oxygen indicator exhibited a linear response to DO in the range 0.23-10 mg/L with a detection limit of 0.077 mg/L. The LMB-hydrogel indicator was successfully explored for visual evaluation of vacuum degree during food packaging. The LMB-hydrogel, with the advantages of low cost, ease of preparation, as well as facile use, is a promising visual indicator for both gaseous and dissolved oxygen, especially for in-house usage.

Rapid preparation of injectable dual-network hydrogels for biomedical applications using UV-triggered sulfhydryl click reactions

The use of hydrogels to mimic natural cartilage implantation can effectively solve the current problems of insufficient cartilage donors and low rate of injury healing. In particular, injectable hydrogels are less invasive in clinical applications and better able to fill uneven injury surfaces. Here, we prepared NorCS and CS-SH by modifying chitosan with 5-norbornene-2-carboxylic acid and N-Acetyl-L-cysteine, respectively. Dual-network hydrogels were prepared by using UV-triggered thiol-ene click reaction between NorCS and CS-SH and the metal coordination between SA and Ca2+. The prepared hydrogels can be cross-linked quickly and exhibit excellent degradability, self-healing and injectable properties. At the same time, the hydrogel also showed good cytocompatibility and could significantly restore the motor function of mice. This study provides an effective strategy for preparing injectable hydrogels capable of rapid cross-linking.

Preparation and properties of hydrogels with different forms of nanocellulose and low methoxyl pectin

Preparation and properties of hydrogels with different forms of nanocellulose and low methoxyl pectin

Gels/Hydrogels in Different Devices/Instruments-A Review.

Owing to their physical and chemical properties and stimuli-responsive nature, gels and hydrogels play vital roles in diverse application fields. The three-dimensional polymeric network structure of hydrogels is considered an alternative to many materials, such as conductors, ordinary films, constituent components of machines and robots, etc. The most recent applications of gels are in different devices like sensors, actuators, flexible screens, touch panels, flexible storage, solar cells, batteries, and electronic skin. This review article addresses the devices where gels are used, the progress of research, the working mechanisms of hydrogels in those devices, and future prospects. Preparation methods are also important for obtaining a suitable hydrogel. This review discusses different methods of hydrogel preparation from the respective raw materials. Moreover, the mechanism by which gels act as a part of electronic devices is described.

Single-Component Cellulose Acetate Sulfate Hydrogels for Direct Ink Writing 3D Printing.

Hydrogels, typically favored for 3D printing due to their viscoelasticity, are now trending toward ecofriendly alternatives amid growing environmental concerns. In this study, we crafted cellulose-based hydrogels, specifically employing cellulose acetate sulfate (CAS). By keeping the acetyl group substitution degree (DSacetyl = 1.8) and CAS molecular weight constant, we varied rheological properties by adjusting sulfate group substitution (DSsulfate = 0.4, 0.7, and 1.0) and CAS concentration (2-5 wt %). Rheological characterizations, including shear-thinning, yield stress, and thixotropy, were performed to identify optimal conditions for formulating CAS hydrogel ink in direct ink writing for 3D printing under selected experimental conditions. Based on rheological findings, CAS hydrogels with DSsulfate 0.7 and concentration of 4 wt % was used for 3D printing, with subsequent evaluation of printing metrics. Additionally, the effect of ionic cross-linking using Ca2+ ions on the structural integrity of 3D-printed structures was evaluated, demonstrating effective preservation through reinforced polymer networks. The shrinking and swelling behaviors of the 3D-printed structures were also significantly affected by this ionic cross-linking. Building on these findings, this work could broaden the range of cellulose derivatives available for the preparation of cellulose-based hydrogels for 3D printing.

Photo-crosslinking methacrylated-amylopectin/polyacrylamide hydrogels loading curcumin for applications as degradable, injectable, and antibacterial wound dressings

The preparation of biodegradable and antibacterial hydrogels has important clinical value. In this work, a novel strategy has been developed to prepare degradable hydrogel dressings without chemical crosslinking agent using methacrylate anhydride (MA)-modified amylopectin (APMA) and polyacrylamide (PAM). After introducing CC bonds, APMA/PAM hydrogels can be formed under light irradiation. This strategy improves the gelling ability of AP and degradation properties of the hydrogel by avoiding the addition of crosslinking agent. The degradation rate of APMA/PAM hydrogel is 74.04 ± 0.69 % within 12 weeks, while that of APMA/PAM hydrogel containing crosslinking agent is only 38.5 ± 0.1 %. The APMA/PAM hydrogel loading curcumin (Cur) (APMA/PAM-Cur) exhibits high antibacterial efficiency of 98.29 ± 0.41 % and 97.18 ± 0.81 % against S. aureus and E. coli, respectively, with light irradiation. Animal experiments show that the APMA/PAM-Cur hydrogel reduces the infiltration of inflammatory factors, increases the density of collagen, and makes the newly formed granulation tissue thicker and tighter. This study not only proves the promising potential of the APMA/PAM-Cur hydrogel as degradable and antibacterial wound dressing for clinical treatment, but also provides a new strategy for developing low-cost, degradable, and antibacterial wound dressings and reducing antibiotic abuse and environmental pollution caused by medical waste.

Light Switchable Bioorthogonal Reaction Manifold for Modulation of Hydrogel Properties.

Chemical reaction systems that can occur via multiple pathways in a controllable fashion are highly attractive for advanced materials applications and biological research. In this report, we introduce a bioorthogonal reaction manifold based on a chalcone pyrene (CPyr) moiety that can undergo either red-shifted photoreversible [2 + 2] cycloaddition or thiol-Michael addition click reaction. By coupling the CPyr to a water-soluble poly(ethylene glycol) end group, we demonstrate the efficient polymer dimerization and cleavage by blue light (λ = 450 nm) and UV light (λ = 340 nm), respectively. In the absence of light, CPyr rapidly reacts with thiols in aqueous environments, enabling fast and efficient polymer end-group functionalization. The chemical reaction manifold was further employed in polymer cross-linking for the preparation of hydrogels whose stiffness and morphology can be modulated by different photonic fields or the addition of a thiol cross-linker. The photoreversible cycloaddition and thiol-Michael addition click reaction can be used in conjunction for spatial and temporal conjugation of a streptavidin protein. Both cross-linking conditions are nontoxic to various cell lines, highlighting their potential in biomaterials applications.