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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. [ABSTRACT FROM AUTHOR]

On‐chip integrated meta‐optics hold tremendous potential for optical imaging and display applications compatible with integrated photonic devices. Despite recent endeavors in multi‐dimensional image display, it remains a challenge to realize dynamic holography applications with on‐chip integration scheme and facile accessible tuning approach. Herein, an on‐chip hydrogel‐waveguiding platform with single‐step fabrication is demonstrated for dynamic colorful holography. By exploiting the optical tunable property of the waveguiding hydrogel, the on‐chip hydrogel metasurface enables optical concealment ON/OFF and dynamic dual‐channel holographic switch within 310 ms through a simple exhalation process. Furthermore, utilizing the waveguiding hydrogel dispersion and the correlation between extraction efficiency and relative humidity, a color‐mixed holographic image is encrypted and successfully exhibited at specific humidity condition. Beyond the conventional static on‐chip monochromatic holography, such a dynamic on‐chip hydrogel platform enjoys satisfactory humidity‐responsivity, high integration capability, full‐color potential, and zero‐order diffraction interference‐free, which suggests potential applications in active optical information concealment/encryption, full‐color holography, and next‐generation wearable AR devices. [ABSTRACT FROM AUTHOR]

Development of a carrier with controlled release manner for methotrexate (MTX), an anticancer drug with short elimination half-life of 3-10 h, is important to overcome undesired side effects of conventional systems. This study demonstrated the synthesis of a pH-sensitive magnetic hydrogel nanocomposite based on montmorillonite (MMT), magnetite (Fe3O4), and alginate (Alg) for extended release of MTX. MMT-Fe3O4 with different amounts of MMT, were prepared by growth of Fe3O4 nanoparticles on the surface of MMT. Then, the MMT-Fe3O4-MTX-Alg nanocomposite beads were prepared by coating of well dispersed MMT-Fe3O4-MTX with Alg. The characterization was investigated using FTIR, XRD, DLS, FESEM-EDX, TGA, and VSM techniques. By introducing 1 g of MMT in hydrogel beads, the encapsulation efficiency and loading content were enhanced to 99.34% and 18.71%, respectively. Pure drug exhibits a burst release of 100% within 4 h. Whereas for MMT (1)-Fe3O4-MTX-Alg, less burst release of 12.4% and 27.6% in the gastric and intestinal fluid was obtained, respectively within 4 h. This phenomenon leads to the beads remaining intact passing through the stomach, but the release rate is done at an acceptable rate at the relatively alkaline environment of the intestine. The release kinetics of MTX from the nanocomposite beads follows the Korsmeyer-Peppas model. Finally, MTT assay and RT-PCR analysis were followed on MDA-MB-231 breast cancer cells, to assess their anti-proliferative, apoptotic and antiapoptotic effects. MMT-Fe3O4-MTX-Alg significantly reduced the percentage of viable cells, with a high down-regulation in the expression level of the anti-apoptotic gene (Bcl-2), and up-regulation in the apoptotic gene (Bax). [ABSTRACT FROM AUTHOR]

A sensitive platform was constructed for on-site detection of chlorpyrifos by immobilizing a core–shell structured NaYbF 4 @NaYF 4 : Yb3+, Tm3+ UCNPs/MnO 2 composite in calcium alginate hydrogel kit. Specifically, the designed UCNPs fluorescent probe (NaYbF 4 @NaYF 4 : Yb3+, Tm3+) has the blue-violet emission. After mixing with MnO 2 nanoflakes, the blue-violet upconversion (UC) emission is quenched. Thiocholine (TCh), formed through acetylcholinesterase (AChE)-mediated catalysis, reduces MnO 2 nanoflakes to Mn2+ ions, thereby restoring the system's fluorescence. The introduction of chlorpyrifos inhibits AChE activity, accompanied by the quenching of the fluorescence signal. Based on the blue-violet UC emission signal response to chlorpyrifos, fluorescent photos were taken by smartphones. Utilizing a Python-assisted analysis platform, a "one-run" operation simultaneously captures image grayscale values, gray images, and differentiated pseudo-color images related to pesticide concentrations, enabling real-time and rapid quantitative analysis of pesticides. [Display omitted] On-site quantitative analysis of pesticide residues is crucial for monitoring environmental quality and ensuring food safety. Herein, we have developed a reliable hydrogel portable kit using NaYbF 4 @NaYF 4 : Yb, Tm upconversion nanoparticles (UCNPs) combined with MnO 2 nanoflakes. This portable kit is integrated with a smartphone reader and Python-assisted analysis platform to enable sample-to-result analysis for chlorpyrifos. The novel UCNPs maximizes energy donation to MnO 2 acceptor by employing 100 % of activator Yb3+ in the nucleus for NIR excitation energy collection and confining emitter Tm3+ to the surface layer to shorten energy transfer distance. Under NIR excitation, efficient quenching of upconversion blue-violet emission by MnO 2 nanoflakes occurs, and the quenched emission is recovered with acetylcholinesterase-mediated reactions. This process allows for the determination of chlorpyrifos by inhibiting enzymatic activity. The UCNPs/MnO 2 were embedded to fabricate a hydrogel portable kit, the blue-violet emission images captured by smartphone were converted into corresponding gray values by Python-assisted superiority chart algorithm which achieves a real-time rapid quantitative analysis of chlorpyrifos with a detection limit of 0.17 ng mL−1. At the same time, pseudo-color images were also added by Python in "one run" to distinguish images clearly. This sensor detection with Python-assisted analysis platform provides a new perspective on pesticide monitoring and broadens the application prospects in bioanalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrogels derived from fluorenylmethoxycarbonyl (Fmoc)-conjugated amino acids and peptides demonstrate remarkable potential in biomedical applications, including drug delivery, tissue regeneration, and tissue engineering. These hydrogels can be injectable, offering a minimally invasive approach to hydrogel implantation. Given their potential for prolonged application, there is a need for non-destructive evaluation of their properties over extended periods. Thus, we introduce a hydrogel characterization platform employing single-walled carbon nanotubes (SWCNTs) as near-infrared (NIR) fluorescent probes. Our approach involves generating supramolecular self-assembling hydrogels from aromatic Fmoc-amino acids. Integrating SWCNTs into the hydrogels maintains their structural and mechanical properties, establishing SWCNTs as optical probes for hydrogels. We demonstrate that the SWCNT NIR-fluorescence changes during the gelation process correlate to rheological changes within the hydrogels. Additionally, single particle tracking of SWCNTs incorporated in the hydrogels provides insights into differences in hydrogel morphologies. Furthermore, the disassembly process of the hydrogels can be monitored through the SWCNT fluorescence modulation. The unique attribute of SWCNTs as non-photobleaching fluorescent sensors, emitting at the biologically transparent window, offers a non-destructive method for studying hydrogel dynamics over extended periods. This platform could be applied to a wide range of self-assembling hydrogels to advance our understanding and applications of supramolecular assembly technologies. [ABSTRACT FROM AUTHOR]

Hypothermic preservation (HP) is highly desired for the maintenance of the viability of living cell specimens, e.g. rare cells in whole-blood samples or therapeutic cells, in an unfrozen state. However, the extension of the viable preservation time is a challenge because of the multiple injuries suffered by hypothermically preserved cells. Here, based on a dynamic bond crosslinked zwitterionic hydrogel, we established a sensing preservation system that could monitor the levels of reactive oxygen species (ROS) via real-time electronic signals and intelligent control of antioxidant addition, to completely prevent an excess of ROS in the whole-cell specimen. Furthermore, the hydrogel-based system can counter the extracellular-matrix-loss-induced anoikis of living cells. Based on the design aimed at affording protection against two primary HP injuries (i.e. ROS overproduction and anoikis) to cells, this system extended the preservation time of cell specimens under refrigerated conditions to 24 days. After preservation, the use of a mild cell retrieval process guaranteed the activity of the preserved living cells. This work not only possesses the potential to facilitate intelligent cell-based clinical applications, but also paves the way for the preparation of living materials that can host programmed cells with long-term survival. An intelligent system based on a zwitterionic sensing hydrogel is established, which can afford ultra-long hypothermic cell-preservation times of up to 24 days. The system enables the real-time monitoring of ROS overproduction and intelligent antioxidant addition, because of the merging of the smart hydrogel with a computer intelligent detection and control system. Furthermore, the automatic addition of an antioxidant according to the ROS-signal changes produced by the ZBA hydrogel effectively prevented HP lesions, including ROS over-production and ECM loss, in the preserved living cells. Subsequently, the system could also be gently dissociated, to retrieve the preserved cells. This work provides a solution for the real-time monitoring and long-term HP of living specimens, which holds the promise of benefiting cell-based medicine and the development of genetically programmed cell-based living materials. [Display omitted] [ABSTRACT FROM AUTHOR]

The application of adhesive conductive hydrogel materials in flexible sensors has been extensively studied. However, existing adhesive hydrogel sensor materials have problems such as poor adhesion, low conductivity, and difficulty in balancing mechanical and adhesive properties, which limit their practical applications. In this study, we propose a simple and economical method to fabricate double‐network hydrogels for flexible strain sensors by dissolving acrylamide (AM), chitosan (CS), polyethylene glycol (PEG) and gelatin (Gel) in a mixed solvent of deionized water and a food‐grade phosphate. The prepared AM/CS/PEG/Gel (ACPG) hydrogel exhibits excellent toughness (maximum stress of 154 kPa, maximum elongation of 2256%), self‐adhesiveness (maximum adhesion strength to wood of 17.2 kPa), and high conductivity (2.33 S/m). Compared with similar adhesive hydrogels, the conductivity of ACPG hydrogel is significantly improved. Therefore, ACPG hydrogel can be used as an ideal material for flexible sensors, and has broad application potential in wearable devices and human‐computer interaction. [ABSTRACT FROM AUTHOR]

Bioinspired synthetic materials can be designed as reliable, cost‐effective, and fully controlled alternatives to natural biomaterials for treating damaged tissues and organs. However, several hurdles need to be overcome for clinical translation, particularly for biomaterials gelled in situ. These include the potential toxicity of chemical crosslinkers used in the materials' assembly or breakdown products they generate and the challenges of fine‐tuning the mechanical properties of the materials. Here, a minimalistic, adhesive soft material is developed by screening hundreds of potential formulations of self‐assembling, custom‐designed collagen‐like peptide sequences for the in situ formation of tissue‐bonding 3D hydrogels. Nine promising formulations for tissue repair are identified using a low‐volume and rapid combinatory screening approach. It is shown that simply varying the ratio of the two key components promotes adhesion and fine‐tunes the material's mechanical properties. The materials' skin and heart repair capabilities are assessed in vitro and clinically relevant animal models. The materials are also tested for corneal applications using ex vivo pig cornea models complemented by in vitro cell compatibility assays. [ABSTRACT FROM AUTHOR]

Charged double network (DN) hydrogels are widely studied for their desirable mechanical strength and tunable properties. In this work, the influence of polymer concentration on microstructure and properties of agarose/polyacrylic acid DN hydrogels is studied. Agarose, the first network, is a brittle biopolymer, while polyacrylic acid (PAAc) is a weak polyelectrolyte. The microstructure, visualized in liquid environment, displays an agarose scaffold coated and interconnected by PAAc, deviating from the common assumption of an entangled double network. Importantly, the charging of PAAc in the hydrogel is regulated not only by the pH and weak polyelectrolyte effects, but also by the restricted swelling of the double network, and hence, it is an inherent regulation mechanism of charged hydrogels. The interactions between the hydrogel and the ionic environment induce microstructural changes and charging of the double network, impacting surface properties such as topography, stiffness, and adhesion, which are spatially resolved by liquid‐environment atomic force microscopy. The responsiveness of the DN hydrogels significantly depends on both polymer concentrations and ion concentrations. These findings provide insights into the responsive behavior of double network hydrogels and reveal universal mechanisms for charged hydrogels, which can guide the future development of functional soft materials. [ABSTRACT FROM AUTHOR]

Catalytic control over molecular self‐assembly provides a powerful approach to regulate the structures as well as the functionalities of supramolecular materials. Revealing how the catalysts affect the molecular self‐assembly process is crucial for rational design and control of the supramolecular self‐assembly systems. Herein, relying on a hydrazone‐based dynamic supramolecular hydrogel system, the effects of various nucleophilic catalysts on the self‐assembly of the hydrogels are investigated, demonstrating that the catalyst influences the hydrogelators self‐assembly via facilitating both the reaction and hydrogelators nucleation processes. The catalyst with higher catalytic activity accelerates the formation thereon the self‐assembly of hydrazone‐based hydrogelators, leading to hydrogels with more branched networks and higher stiffness. Importantly, we also verify that the catalysts, depending on the molecular structure, can also accelerate the self‐assembly process by affecting the hydrogelators nucleation process. These findings not only add more details to the effects of nucleophilic catalysts on the hydrazone‐based hydrogelation system, but also suggest that both the catalysis activity and chemical structures should be considered for catalytically controlled molecular self‐assembly. [ABSTRACT FROM AUTHOR]

In this current study, hydrogels based on acacia gum (AG), polyacrylamide (PAM), and carboxymethyl tamarind kernel gum (CMTKG) were successfully developed and ciprofloxacin (drug) incorporated into it. To optimize the hydrogel, the concentrations of crosslinker and initiator were varied, and their effects on the swelling were examined. The hydrogel was subjected to characterization techniques such as Powder X‐ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Attenuated Total Reflection‐Fourier Transform Infrared spectroscopy (ATR‐FTIR), and Thermogravimetric analysis (TGA). The hydrogel swelling and in vitro drug release were assessed in pH 1.2 and 7.4 buffer solutions. The findings revealed that an alkaline pH yielded superior results for the swelling and in vitro drug release experiments compared to an acidic pH. The drug release kinetic of the ciprofloxacin‐loaded AG/PAM/CMTKG hydrogel followed the Korsmeyer–Peppas model, demonstrating non‐fickian diffusion at pH 7.4 and fickian mechanism at pH 1.2. The pH‐dependent behavior of ciprofloxacin‐loaded AG/PAM/CMTKG hydrogel displayed its potential implications for site‐specific ciprofloxacin release. [ABSTRACT FROM AUTHOR]

Adhesive hydrogels play a crucial role in numerous applications across fields such as wound dressing, biomedical implants, and flexible electronics. Despite recent efforts on hydrogel design, reconciling the conflicting requirements of adaptability to rough surfaces and intrinsic strength remains elusive for self‐adhesive hydrogels. To address this challenge, a novel strategy is proposed where conformal contact between hydrogels and solids is initially established in a weak state, followed by reinforcement to enhance strength and toughness. Illustrating this approach, bovine serum albumin (BSA) is employed to incorporate a flexible synthetic polymer network, resulting in soft and adhesive organohydrogels (OHGs) with instantaneous and reversible adhesion on various substrates, providing fault‐tolerant operation convenience. A brief on‐demand heating step transforms them into a strong and supra‐adhesive state by forming a rigid BSA network and establishing a double network (DN) structure. The resulting BSA based DN OHGs demonstrate remarkably enhanced bulk mechanical strength and exceptional interfacial toughness on diverse nonporous solid substrates, allowing for on‐demand permanent fixation. This approach integrates fault‐tolerance and permanent fixation into a single material, highlighting the potential of these natural albumin based OHGs as advanced functional materials for diverse applications, including artisanal restoration, and all‐season flexible sensors. [ABSTRACT FROM AUTHOR]

AbstractPurposeMethodsResultsConclusionsThis comprehensive review is designed to elucidate the transformative role and multifaceted applications of ocular hydrogels in contemporary ophthalmic therapeutic strategies, with a particular emphasis on their capability to revolutionize drug delivery mechanisms and optimize patient outcomes.A systematic and structured methodology is employed, initiating with a succinct exploration of prevalent ocular pathologies and delineating the corresponding therapeutic agents. This serves as a precursor for an extensive examination of the diverse methodologies and fabrication techniques integral to the design, development, and application of hydrogels specifically tailored for ophthalmic pharmaceutical delivery. The review further scrutinizes the pivotal manufacturing processes that significantly influence hydrogel efficacy and delves into an analysis of the current spectrum of hydrogel-centric ocular formulations.The review yields illuminating insights into the escalating prominence of ocular hydrogels within the medical community, substantiated by a plethora of ongoing clinical investigations. It reveals the dynamic and perpetually evolving nature of hydrogel research and underscores the extensive applicability and intricate progression of transposing biologics-loaded hydrogels from theoretical frameworks to practical clinical applications.This review accentuates the immense potential and promising future of ocular hydrogels in the realm of ophthalmic care. It not only serves as a comprehensive guide but also as a catalyst for recognizing the transformative potential of hydrogels in augmenting drug delivery mechanisms and enhancing patient outcomes. Furthermore, it draws attention to the inherent challenges and considerations that necessitate careful navigation by researchers and clinicians in this progressive field. [ABSTRACT FROM AUTHOR]

Droplet‐based electricity generators (DEGs) have emerged as innovative devices capable of transducing the kinetic energy of falling water droplets into electrical power, thereby presenting a promising solution for ambient energy harvesting. For effective application, DEGs must exhibit transparency and flexibility to facilitate aesthetic integration and optical/mechanical adaptability for utilization on natural objects and wearable devices. In this study, a hydrogel‐based DEG (Hy‐DEG) designed is proposed to be seamlessly integrated into everyday environments without compromising design or functionality. With the intrinsic characteristics of hydrogel, the Hy‐DEG exhibits superior optical transmittance (≈99%) and stretchability (≈70% of its original length), generating the electrical output performance of ≈45 V of voltage, 15 µA of current, and 42 µW of maximum peak power, with single droplet impact. This capability of the Hy‐DEG can operate electronic devices for environmental monitoring while maintaining seamless integration with commonly encountered surfaces. In this context, this study elucidates the characteristics of hydrogel bestowing novel functionalities upon the DEG, expanding the potential for energy harvesting in residential and commercial contexts. The implications of this research extend beyond conventional energy generation, fostering the development of self‐powered, transparent, and flexible devices. [ABSTRACT FROM AUTHOR]

With the wide application of portable electronic devices, zinc–ion hybrid supercapacitors (ZIHCs) have aroused great interest. However, balancing the low‐temperature performance and high energy density of ZIHCs remains a huge challenge. Herein, a zwitterionic hydrogel electrolyte (ZHE) loaded with carboxymethylcellulose and MXene is designed for ZIHCs, which shows excellent frost resistance and high output voltage. Carboxymethylcellulose and MXene enhance the flexibility and conductivity of the zwitterionic hydrogel electrolyte. Moreover, When ZnCl2 is introduced into a gel electrolyte, it induces an increase in the rate of ion transport, which enables a broadening of the operating temperature of the hydrogel (−40 °C–25 °C). As a result, Zn//AC ZIHCs based on ZHE show a high voltage window of 2 V, a high energy density (specific capacity) of 137 Wh kg−1 (247 F g−1), and the potential for wearable devices. This study will provide an effective strategy for the design of hydrogel ZIHCs with wide voltage windows, high energy density, and high practicality. [ABSTRACT FROM AUTHOR]

Nature uses complex self‐assembly pathways to access distinct functional non‐equilibrium self‐assemblies. This remarkable ability to steer same set of biomolecules into different self‐assembly states is done by avoiding thermodynamic pit. In synthetic systems, on demand control over 'Pathway Complexity' to access self‐assemblies different from equilibrium structures remains challenging. Here we show versatile non‐equilibrium assemblies of the same monomer via alternate assembly pathways. The assemblies nucleate using non‐classical or classical nucleation routes into distinct metastable (transient hydrogels), kinetic (stable hydrogels) and thermodynamic structures [(poly)‐crystals and 2D sheets]. Initial chemical and thermal inputs force the monomers to follow different assembly pathways and form soft‐materials with distinct molecular arrangements than at equilibrium. In many cases, equilibrium structures act as thermodynamic sink which consume monomers from metastable structures giving transiently formed materials. This dynamics can be tuned chemically or thermally to slow down the dissolution of transient hydrogel, or skip the intermediate hydrogel altogether to reach final equilibrium assemblies. If required this metastable state can be kinetically trapped to give strong hydrogel stable over days. This method to control different self‐assembly states can find potential use in similar biomimetic systems to access new materials for various applications. [ABSTRACT FROM AUTHOR]

Electroactive scaffolds are increasingly used to mimic the microenvironment of electroactive tissues such as the heart and nerves. Multi-network hydrogels have emerged as an important platform in the field of tissue engineering. In this study, alginate (Alg)-based conductive and multi-network nanocomposite hydrogels were prepared and characterized as promising scaffolds for electroactive tissues. Alg, which is derived from natural sources, was modified with methacrylate (AlgMA) to render it photosensitive (photoactive). Multiwall carbon nanotubes (MWCNTs) were chosen as potential nanomaterials for electrical conductivity. MWCNTs were modified with –COOH groups to produce MWCNT–COOH nanomaterials. Nanocomposite hydrogels were fabricated by incorporating 0.5%, 1.0%, and 3.0 wt% of MWCNT–COOH into the AlgMA network. The hydrogel scaffolds were assessed for their chemical, physical, mechanical, electrical, and biological characteristics. This study demonstrated that incorporating modified MWCNTs into an AlgMA network enhances its electrical activity. According to our results, good rheological properties, natural tissue-like mechanical properties, optimal electrical conductivity, and biological performance make AlgMA/MWCNT–COOH multi-network nanocomposite hydrogels crucial in the field of electroactive tissues. [ABSTRACT FROM AUTHOR]

Traditional hydrogels with soft and wet features often show poor mechanical properties due to their single cross‐linked network and amorphous structure. Hence, there are still great challenges in the preparation of strong and elastic hydrogels with superior lubrication performance for broader applications. Inspired by the biphasic structure of natural cartilage, the tough layered P(AM‐AA)‐Fe3+ (poly(acrylamide‐co‐acrylic acid)‐Fe3+) hydrogels are prepared via a sodium citrate treatment‐induced surface dissociation approach. The top lubricating layer with porous structure and high water content can achieve ultra‐low friction (friction coefficient [COF] ~ 0.010 at 5 N load), whereas the bottom stiff layer with compact structure demonstrates excellent load‐bearing capacity. The layered structure could provide hydrogels with excellent physical functions such as high strength (~7.1 MPa), superior lubrication (COF ~ 0.018, 10 N), and wear resistance (COF < 0.05, 5 N, 18,000 cycles), thereby expanding the application of hydrogel in the field of bioinspired lubrication materials. [ABSTRACT FROM AUTHOR]

Ionic conductive hydrogels (ICHs) have recently gained prominence in biosensing, indicating their potential to redefine future biomedical applications. However, the integration of these hydrogels into sensor technologies and their long‐term efficacy in practical applications pose substantial challenges, including a synergy of features, such as mechanical adaptability, conductive sensitivity, self‐adhesion, self‐regeneration, and microbial resistance. To address these challenges, this study introduces a novel hydrogel system using an imidazolium salt with a ureido backbone (UL) as the primary monomer. Fabricated via a straightforward one‐pot copolymerization process that includes betaine sulfonate methacrylate (SBMA) and acrylamide (AM), the hydrogel demonstrates multifunctional properties. The innovation of this hydrogel is attributed to its robust mechanical attributes, outstanding strain responsiveness, effective water retention, and advanced self‐regenerative and healing capabilities, which collectively lead to its superior performance in various applications. Moreover, this hydrogel exhibited broad‐spectrum antibacterial activity. Its potential for biomechanical monitoring, especially in tandem with contact and noncontact electrocardiogram (ECG) devices, represents a noteworthy advancement in precise real‐time cardiac monitoring in clinical environments. In addition, the conductive properties of the hydrogel make it an ideal substrate for electrophoretic patches aimed at treating infected wounds and consequently enhancing the healing process. [ABSTRACT FROM AUTHOR]

An asymmetrical wound dressing functions akin to human skin by serving as a protective barrier between a wound and its immediate environment. However, significant challenges persist concerning the robust adhesion and asymmetrical adhesion properties of hydrogels, particularly when applied in emergency hemostasis and wound healing contexts. Herein, the study has successfully synthesized hydrogel patches with Janus asymmetric‐adhesion, denoted as HGO‐C, exclusively comprised of natural polymers. This achievement is realized through the assembly of adhesive hydrogel (HGO) and non‐adhesive hydrogel (CGC), thereby amalgamating their distinct functionalities. The non‐adhesive hydrogel component served as a physical shield and safeguarding the wound against contamination, while the adhesive hydrogel, when in contacted with the wound surface, firmly adhered to it, swiftly arresting bleeding and facilitating wound healing. Cytocompatibility tests, hemolysis tests, antibacterial assays, and coagulation assays demonstrated excellent biocompatibility, antibacterial, and hemostatic properties of HGO‐C. Finally, the in vivo experiments, including a liver hemorrhage assay and a wound healing assay, unequivocally showed the rapid hemostatic and enhanced wound healing capabilities of HGO‐C. Consequently, these distinctive hydrogel patches, derived from natural polymers and characterized by their asymmetric adhesion properties, may have great potential for real‐life usage in clinical patients. [ABSTRACT FROM AUTHOR]

Next to the choice of a material, the crosslinking characteristics play an important role in the development of hydrogels for applications in the biomedical field. By decreasing crosslinking time or concentration one can reduce the density of the network and hence the stiffness of the hydrogel. However, at the same time in many cases the stability of the matrix is significantly reduced, leading to a rapidly degrading hydrogel structure. In this study, we evaluate and compare two different crosslinking methods while maintaining the material chemistry. The hydrogel system evaluated consisted of oxidized hyaluronic acid and gelatin, and it was crosslinked with microbial transglutaminase. We found that by in situ crosslinking (CL) instead of post CL we can significantly increase the stability of the hydrogel while maintaining the matrix stiffness. Encapsulated embryonic mouse fibroblasts showed an increased viability in in situ crosslinked samples. These findings indicate that it is possible to change hydrogel parameters independently, even if they are otherwise interrelated. [ABSTRACT FROM AUTHOR]

Temperature‐responsive hydrogels, or thermogels, have emerged as a leading platform for sustained delivery of both small molecule drugs and macromolecular biologic therapeutics. Although thermogel properties can be modulated by varying the polymer's hydrophilic‐hydrophobic balance, molecular weight and degree of branching, varying the supramolecular donor‐acceptor interactions on the polymer remains surprisingly overlooked. Herein, to study the influence of enhanced hydrogen bonding on thermogelation, we synthesized a family of amphiphilic polymers containing urea and urethane linkages using quinuclidine as an organocatalyst. Our findings showed that the presence of strongly hydrogen bonding urea linkages significantly enhanced polymer hydration in water, in turn affecting hierarchical polymer self‐assembly and macroscopic gel properties such as sol‐gel phase transition temperature and gel stiffness. Additionally, analysis of the sustained release profiles of Aflibercept, an FDA‐approved protein biologic for anti‐angiogenic treatment, showed that urea bonds on the thermogel were able to significantly alter the drug release mechanism and kinetics compared to usage of polyurethane gels of similar composition and molecular weight. Our findings demonstrate the unrealized possibility of modulating gel properties and outcomes of sustained drug delivery through judicious variation of hydrogen bonding motifs on the polymer structure. [ABSTRACT FROM AUTHOR]

Stem cell-derived β-cells (SC-BCs) represent a potential source for curing diabetes. To date, in vitro generated SC-BCs display an immature phenotype and lack important features in comparison to their bona-fide counterparts. Transplantation into a living animal promotes SC-BCs maturation, indicating that components of the in vivo microenvironment trigger final SC-BCs development. Here, we investigated whether cues of the pancreas specific extracellular matrix (ECM) can improve the differentiation of human induced pluripotent stem cells (hiPSCs) towards β-cells in vitro. To this aim, a pancreas specific ECM (PanMa) hydrogel was generated from decellularized porcine pancreas and its effect on the differentiation of hiPSC-derived pancreatic hormone expressing cells (HECs) was tested. The hydrogel solidified upon neutralization at 37 °C with gelation kinetics similar to Matrigel. Cytocompatibility of the PanMa hydrogel was demonstrated for a culture duration of 21 days. Encapsulation and culture of HECs in the PanMa hydrogel over 7 days resulted in a stable gene and protein expression of most β-cell markers, but did not improve β-cell identity. In conclusion, the study describes the production of a PanMa hydrogel, which provides the basis for the development of ECM hydrogels that are more adapted to the demands of SC-BCs. [ABSTRACT FROM AUTHOR]

The research introduces a novel method for creating drug-loaded hydrogel beads that target anti-aging, anti-oxidative, and anti-inflammatory effects, addressing the interconnected processes underlying various pathological conditions. The study focuses on the development of hydrogel beads containing anti-aging compounds, antioxidants, and anti-inflammatory drugs to effectively mitigate various processes. The synthesis, characterization and in vitro evaluations, and potential applications of these multifunctional hydrogel beads are discussed. A polymeric alginate-orange peel extract (1:1) hydrogel was synthesized for encapsulating fish oil. Beads prepared with variable fish oil concentrations (0.1, 0.3, and 0.5 ml) were characterized, showing no significant decrease in size i.e., 0.5 mm and a reduction in pore size from 23 to 12 µm. Encapsulation efficiency reached up to 98% within 2 min, with controlled release achieved upto 45 to 120 min with increasing oil concentration, indicating potential for sustained delivery. Fourier-transform infrared spectroscopy confirmed successful encapsulation by revealing peak shifting, interaction between constituents. In vitro degradation studies showed the hydrogel's biodegradability improved from 30 to 120 min, alongside anti-inflammatory, anti-oxidative, anti-collagenase and anti-elastase activities, cell proliferation rate enhanced after entrapping fish oil. In conclusion, the synthesized hydrogel beads are a promising drug delivery vehicle because they provide stable and effective oil encapsulation with controlled release for notable anti-aging and regenerative potential. Targeted delivery for inflammatory and oxidative stress-related illnesses is one set of potential uses. Further research may optimize this system for broader applications in drug delivery and tissue engineering. [ABSTRACT FROM AUTHOR]

Shape‐morphing hydrogels can mimic the dynamism of living creatures and are popular for designing soft machines, such as actuators and robots. However, most existing shape‐morphing hydrogels present a single morphing pathway between two shapes, sequential and multistage shape‐morphing in real scenarios has rarely been captured. Although a strategy that assembles functional hydrogel components has been reported, it is likely to simultaneously increase the complexity and weaken the versatility of hydrogel machines. Here, a light‐encoding strategy based on the dynamic coordination between the ferric iron and carboxyl group (Fe3+─COO−) to integrate the frame and actuating units into a single hydrogel without assembly is proposed. The spatiotemporal control of light irradiation is expected to make the light‐encoding process sequential and reprogrammable. Results demonstrate that the light‐encoded patterns determine the morphing route and further activate shape‐morphing owing to swelling mismatch. The actuating units can be successively created by localized irradiation or elaborately turned by re‐coordinating and light‐encoding. This endows the encoded hydrogel with sequential and multistage shape‐morphing behavior, similar to the living creatures. This strategy allows the design of assembly‐free soft machines with sequential and multistage shape‐morphing performance, which will benefit the design of more types of hydrogel machines. [ABSTRACT FROM AUTHOR]

Hydrogels are renowned for their complex structures and unique physicochemical properties, establishing them as key materials in bioenergy harvesting applications. They are used in various applications, including triboelectric nanogenerators, piezoelectric, hydraulic, thermoelectric, and biofuel cells. Among these, hydrogels as key materials for thermoelectric applications represent a technology capable of continuously converting biological energy (thermal energy) into electrical energy. This technology shows great potential and commercial value in body monitoring, energy storage, and human‐machine interaction applications. Given its rapid development, a timely review focusing on the research progress of hydrogels and their composites in thermoelectric technology is presented. This review discusses various types of hydrogels used for thermoelectric power generation and refrigeration, their unique properties, strategies for enhancing their thermoelectric performance, and their applications in the field. Finally, the remaining challenges and feasible strategies are identified for improving the efficiency, stability, application range, and system‐level integration of next‐generation hydrogels for thermoelectric applications. [ABSTRACT FROM AUTHOR]

Two novel 3D bimetallic metal-organic frameworks (MOF) {Cd4Zn(L1)4(DMF)2[NH2(CH3)3]} (1) and {[Cd4Ca(L2)2(bipy)2(H2O)4]·(NO3)2} (2) have been successfully synthesized by using organic ligands {H3L1 = 4-[bis (4-carboxyphenyl) amino] benzoic acid; H4L2 = cyclopenta-1,4-diene-1,2,3,4-tetracarboxylic acid; bipy = 4-[2-(pyridin-4-yl) ethyl] pyridine; DMF: N,N-dimethylformamide} under solvothermal condition, which has been fully characterized by fluorescence spectroscopy, FTIR, single-XRD, EA, SEM, etc. Fluorescence tests were conducted with an excitation wavelength at 365 nm, and the results confirm the excellent photoluminescent performance of both compounds, suggesting their potential applications as green and blue fluorescence materials. Based on the unique advantages of this novel material, we utilized composite 1 as a drug carrier to load Duhuo Jisheng Decoction. Employing non-toxic, biocompatible hydrogel encapsulation, we constructed a novel hydrogel-organic framework composite. Through analyzing the impact of metal gel particles on SW1353 cells, we elucidated the regulatory role of miRNA-27a-3P on the PI3K/Akt/mTOR signaling pathway, indicating the system's potential in inhibiting arthritis development and offering a new avenue for knee osteoarthritis treatment. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the acaricidal efficacy, tolerability of the target species, and residue levels of a thymolcontaining gelatin-based hydrogel developed as a controlled release system for varroosis control. The study was carried out on naturally infested honey bee colonies and results were compared with those of negative and positive control groups. The acaricidal efficacy of the negative control, positive control, and hydrogel treatment was 21.93 ± 2.87%, 81.09 ± 2.30%, and 70.32 ± 2.05%, respectively. For tolerability evaluations, the average number of dead bees per colony was determined to be 60.80 ± 8.01, 297.40 ± 21.4, and 86.80 ± 6.94 for the negative control, positive control, and hydrogel treatment, respectively. The average thymol residues in honey were measured as 0.030 ± 0.022 mg/kg, 5.498 ± 3.346 mg/kg, and 0.168 ± 0.110 mg/kg for the negative control, positive control, and hydrogel treatment, respectively. The average thymol concentrations in beeswax were 0.074 ± 0.047 mg/kg, 1.667 ± 0.855 mg/kg, and 0.476 ± 0.278 mg/kg for the negative control, positive control, and hydrogel treatment, respectively. The controlled release system developed in this study was found to prevent the transport of thymol out of the colony due to its structure, which is well tolerated by bees. Consequently, a single application can achieve longer infestation control. Furthermore, the lack of intervention by bees in the system ensures that bee mortality due to contact toxicity and residue levels in honey and beeswax are low. In addition to these advantages of the system, further development is required to increase the acaricide efficacy in order to make it an ideal alternative to existing varroacidal veterinary medicinal products. [ABSTRACT FROM AUTHOR]

The kinetics of hydrate formation in powder hydrogel systems saturated with aqueous surfactant solutions and stabilized with hydrophobic nanoparticles was studied. The systems were also studied for stability in multiple hydrate formation and dissociation cycles, i.e., for their capacity to maintain the original rate and degree of conversion of water to hydrate in the second and subsequent cycles. [ABSTRACT FROM AUTHOR]

This study explores the synthesis and characterization of superabsorbent hydrogels derived from chemically modified gum Arabic, designed for controlled folic acid release. The synthesis involves a two‐step process: carboxymethylation followed by grafting with 2‐hydroxyethyl methacrylate via gamma irradiation. The resulting hydrogels exhibit enhanced mechanical strength and controlled diffusivity, essential for nutrient delivery systems. Key factors such as copolymer composition and irradiation dose are investigated, affecting the synthesis process. Systematic studies of swelling behaviors reveal that the hydrogel achieves a maximum swelling of 888.1% at 40 °C. The hydrogels are loaded with folic acid, and in vitro, sustained release profiles are examined under various pH conditions. The maximum release of 83.3% is observed after 24 h at pH 7.0, following a Korsmeyer–Peppas release mechanism. Different characterization techniques, confirm the successful synthesis and unique properties of the superabsorbent hydrogels. Rheological behavior analysis, scanning electron microscopy, and biocompatibility assessments provide a comprehensive understanding of the hydrogel structures. Gamma irradiation ensures a homogeneous network structure, crucial for optimal swelling behavior and mechanical properties. This research highlights the potential of eco‐friendly biopolymer hydrogels in precise drug delivery applications, leveraging the safety and process control benefits of gamma irradiation. [ABSTRACT FROM AUTHOR]

Chitosan and pectin are employed here in the formation of biodegradable hydrogels. The addition of cellulose nanowhiskers (CNW) into the hydrogels is accomplished through two methods: by swelling, after the polymeric network formation (Method A), and inclusion in polymer solutions before gelation, with varying CNW content (Method B). Comprehensive physico–chemical, thermal, microscopic, gel fraction, and water vapor transmission analyses are conducted, complemented by antibacterial and viability assessments. CNWs are successfully synthesized and incorporated within the hydrogel by both methods. Moreover, the degradation temperature (Tmax) of hydrogels is higher with CNW (0% CNW: 205.5 °C, 10% CNW: 217.0 °C). CNW aggregates are observed in hydrogels with 20% and 30% content but no aggregation is observed with 4% and 10%. The antimicrobial properties are not affected by the addition of CNW, and the cytotoxicity tests reveal better results with 10% CNW compared with 20%. The study signifies the versatility of CNWs as effective reinforcements, influencing structural, thermal, and biological aspects of the hydrogels. The proposed methodology, emphasizing CNW incorporation, lays the groundwork for innovative biomaterials with promising medical implications. This investigation encourages further exploration and validation of these composite hydrogels in vivo for practical medical use in wound dressings. [ABSTRACT FROM AUTHOR]

Fluorescent hydrogel as an advanced material has been used for anti‐counterfeiting, probe detection, and optical devices. A facile strategy to prepare fluorescent hydrogel is developed by carboxymethyl cellulose (CMC) with Europium(III) and polyvinyl alcohol (PVA). The hydrogel forms a physical cross‐linking network under mild reaction conditions without using volatile organic chemicals. The addition of CMC‐Eu(III) improves the mechanical properties of the hydrogel. At 15% CMC‐Eu(III), the hydrogel reaches its maximum tensile and compressive stress, which are 47.25 ± 10.35 and 10.14 ± 1.90 kPa, respectively. Meanwhile, the hydrogels exhibit a 5D0→7F2 characteristic emission peak assigned to Eu3+, which emits stable red fluorescence under 254 nm ultraviolet (UV) light. When this hydrogel is applied to paper, the paper showed hidden fluorescent dots under UV light. This additive also enhances the mechanical properties of the paper, which reveals the multifunctionality of this fluorescent hydrogel for anti‐counterfeiting and reinforcement. [ABSTRACT FROM AUTHOR]

The slow healing process of diabetic wound due to persisting infections in wound bed, owing to hyperglycemia, makes the search for efficient treatments pending. While it is complicated to increase the wound closure rate in diabetic‐related wounds due to the complex pathology, the treatment of such wound with hydrogels is seen as a promising approach and pursued over the years. However, where is this research currently standing in terms of clinical translation of these different multifunctional and stimuli‐responsive hydrogel bandages to accelerate diabetic foot ulcer healing and help to improve the life of the patients and the future of diabetic wound management? This perspective article will review some of the most important advancements in the field and will conclude with some perspectives, considered as relevant in the clinical context. [ABSTRACT FROM AUTHOR]

Hydrogels have been extensively used for tissue engineering applications due to their versatility in structure and physical properties, which can mimic native tissues. Although significant progress has been made toward designing hydrogels for soft tissue repair, engineering hydrogels that resemble load‐bearing tissues is still considered a great challenge due to their specific mechanophysical demands. Herein, microporous, tough, yet highly compressible poly(vinyl alcohol) (PVA)‐based hydrogels are reported for potential applications in repairing or replacing different load‐bearing tissues. The synergy of freeze‐thawing and the Hofmeister effect, which controlled the spatial arrangement and aggregation of polymer chains, facilitated the formation of microstructured frameworks with tunable porosity. While the maximum mechanical strength, toughness, and stretchability of the engineered hydrogel were ≈390 kPa, ≈388 kJ m−3, and ≈170%, respectively, Young's modulus based on compression testing wasfound to be in the range of ≈0.02–0.30 MPa, highlighting the all‐in‐one mechanically enriched nature of the hydrogel. Furthermore, the minimal swelling and degradation rate of the engineered hydrogel met the specific requirements for load‐bearing tissues. Finally, excellent antibacterial resistance as well as in vitro biocompatibility of the hydrogel demonstrates its potential for the replacement of load‐bearing tissues. [ABSTRACT FROM AUTHOR]

Suppressing the water activity is challenging to achieve high‐performing aqueous zinc ion batteries (AZIBs), especially for its practical climate adaptability. Reconstructing the H‐bond network and repealing the solvation water can effectively reinforce the covalency inside water molecular. Here, a hydrogel electrolyte formula utilizing ClO4− anions and hydrophilic ─NH2 on polyacrylamide chains is shown to bond with water molecules, while the zincophilic glucose preferentially regulate Zn2+ solvation. The multifunctional hydrogel structure can effectively disrupt the intrinsic H‐bond network and inhibit the interface side‐reactions induced by active water. Finally, the delayed freezing point and expanded voltage stability window are realized, which promotes the ZIBs steady operate in a wide temperature range. When operating at 70 and −30 ˚C, the Zn//NVO battery achieves high specific capacity of 488 and 254 mAh g−1, respectively, surpassing most of the previously reported results. Remarkably, the pouch battery delivers the state‐of‐the‐art specific capacity of 438.1 mAh g−1 and realizes a capacity retention of 76.3% after 400 cycles at 200 mA g−1. [ABSTRACT FROM AUTHOR]

In the present work, methanolic extracts from thyme and dittany plants were prepared and characterized in terms of their polyphenolic content through analytical and spectrophotometric techniques. Rosmarinic acid, thymol and carvacrol were found to be the main components of the extracts, which were further biologically assessed for their antioxidant, anti-tyrosinase, anti-lipase and antibacterial activity against Gram-negative and Gram-positive bacteria. As found, thyme extracts exhibited superior antioxidant activity (SC50 at 33.9 μg mL−1), while dittany extracts inhibited the microbial growth to a great extent against Bacillus subtilis strain (MIC at 0.5 mg mL−1) and E. coli strain (MIC at 2 mg mL−1). Furthermore, the thyme extract was proven to strongly inhibit the activity of lipase from Candida rugosa (IC50 at 63.9 μg mL−1), comparable to the standard inhibitor orlistat, while its inhibitory effect against mushroom tyrosinase was weak. On the other hand, the dittany extract presented an inhibitory effect against the tested lipase (IC50 over 500 μg mL−1) and an activation effect against tyrosinase (at concentrations > 500 μg mL−1). Additionally, molecular docking studies of the main compounds of the extracts showed that rosmarinic acid plays a crucial role on the inhibitory activity of the extracts against lipase, while thymol has a stronger effect on inhibiting tyrosinase. Furthermore, both extracts were employed in the preparation of gelatin-deep eutectic solvent (DES) hydrogels that were further studied for their antioxidant and antibacterial activity. The results showed that the incorporation of the extracts offered antibacterial properties to the biopolymer-based hydrogels and enhanced the antioxidant activity of gelatin up to 85%. [ABSTRACT FROM AUTHOR]

Chitosan was subjected to a crosslinking reaction with three polyhydroxylated diacids (glucaric (GlcA), mannaric (ManA), and mucic (MucA) acids) that only differ in the spatial orientation of their hydroxyl groups. This work aimed to obtain experimental evidence of the impact of the three-dimensional arrangement of the crosslinkers on the resulting properties of the products. In all the cases, the products were hydrogels, and their chemical structures were fully elucidated by FT-IR spectroscopy and conductometric titration. Thermogravimetric and morphological studies were also carried out. The specific surface area of all the products was similar and higher than that of native chitosan. Moreover, all hydrogels were characterized in terms of viscoelastic properties and long-term stability under external perturbation. Furthermore, their lead adsorption efficiency and swelling capacity were assessed. Despite the resemblant chemical structure in all the hydrogels, Ch/ManA exhibited the highest lead adsorption capacity, (Ch/ManA: 93.8 mg g−1, Ch/GlcA: 82.9 mg g−1, Ch/MucA: 79.2 mg g−1), while Ch/GlcA exhibited a remarkably higher swelling capacity (i.e., ~30% more than Ch/MucA and ~40% more than Ch/ManA). The results obtained herein evidenced that the selection of the polyhydroxylated crosslinker with the appropriate three-dimensional structure could be crucial to finely adjust the final materials' features. [ABSTRACT FROM AUTHOR]

Tunable hydrogels have gained significant attention in the bioengineering field due to their designer preparation approach. Towards this end, gelatine stands out as a promising candidate owing to its desirable attributes, such as biocompatibility, ability to support cell adhesion and proliferation, biodegradability, and cost-effectiveness. This study presents the preparation of a robust gelatine hydrogel employing sacran aldehyde (SDA) as a natural cross-linker. The resulting SDA-cross-linked gelatine hydrogels (GSDA) display an optimal compressive stress of 0.15 MPa at 50% strain, five times higher than pure gelatine hydrogel. As SDA cross-linking concentration is increased, the swelling capacity of GSDA declines. This decline in swelling capacity, from 80% to 40%, is a result of strong crosslinking of gelatin with SDA. Probing further with FT-IR spectroscopy and SEM at the micron scale unveiled a dual-cross-linking mechanism within the hydrogels. This mechanism encompasses both short- and long-range covalent cross-linking, along with thermo-induced physical cross-linking, resulting in a significant enhancement of the load-bearing capacity of the fabricated hydrogels. [ABSTRACT FROM AUTHOR]

The goal of this study was to explore a route for introducing functionalities into agarose-based hydrogels to tune the physical, chemical, and biological properties. Several agarose derivatives were prepared by homogeneous synthesis, including anionic agarose sulfates (ASs), reactive azido agaroses (AZAs), and cationic agarose carbamates (ACs), as well as agarose tosylates (ATOSs) and agarose phenyl carbonates (APhCs). The products were characterized in terms of their molecular structure and solubility behavior. The results suggest that the native gel-forming ability of agarose is retained if the introduced functionalities are hydrophilic, and the overall degree of substitution is low (DS < 0.5). Thus, functional hydrogels from several agarose derivatives could be obtained. The mechanical stability of the functional hydrogels was decreased compared to native agarose gels but was still in a range that enables safe handling. An increase in mechanical strength could be achieved by blending functional agarose derivatives and agarose into composite hydrogels. Finally, it was demonstrated that the novel functional agarose hydrogels are biocompatible and can potentially stimulate interactions with cells and tissue. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the influence of hydrogel and zinc oxide nanoparticles on quinoa germination and establishment. Various doses of a commercial potassium-based hydrogel (0, 5, 7, and 9 g), each dissolved in one liter of rainwater, were applied. Additionally, 1.5 g of zinc oxide nanoparticles (ZnO-NP) and pre-crushed nitrogen fertilizer, at a rate of 1.6 kg/ha, were added to the solution to achieve a homogeneous mixture. Following the application of hydrogel in the 10-linear-meter rows corresponding to each treatment area in every block, 25 seeds per linear meter of the "Blanca de Juli" quinoa cultivar were sown with a 4 cm spacing between the seeds. Subsequently, a thin layer of soil, approximately 0.5 cm thick, was used to cover the seeds. Ten seedlings were randomly selected and labeled for subsequent evaluations. The experimental design employed in this research was a completely randomized block design. The collected data underwent an analysis of variance, and the means of all the treatments were compared using Tukey's test with a 5% probability. Height and diameter evaluations of the plant neck were conducted every 45 days. The doses used in this study (5, 7, and 9 g of hydrogel per liter of water) significantly enhanced seed germination and increased the number of plants per linear meter (from 82.00 to 90.33) compared to the control dose without hydrogel (14.66), which resulted in an average of one plant per linear meter. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a debilitating joint disease characterized by cartilage degradation, leading to pain and functional impairment. A key contributor to OA progression is the decline in cartilage lubrication. In physiological conditions, synovial fluid (SF) macromolecules like hyaluronic acid (HA), phospholipids, and lubricin play a crucial role in the boundary lubrication of articular cartilage. In early OA, cartilage damage triggers inflammation, altering SF composition and compromising the lubrication layer. This increases friction between mating interfaces, worsening cartilage degradation and local inflammation. Therefore, early-stage restoration of lubrication (by injecting in the joint different classes of compounds and formulations) could alleviate, and potentially reverse, OA progression. In the light of this, a broad variety of lubricants have been investigated for their ability to reduce friction in OA joints and promote cartilage repair in clinical and preclinical studies. This review examines recent advancements in lubricant-based therapy for OA, focusing on natural, bioinspired, and alternative products. Starting from the currently applied therapy, mainly based on natural lubricants as HA, we will present their modified versions, either in hydrogel form or with specific biomimetic moieties with the aim of reducing their clearance from the joint and of enhancing their lubricating properties. Finally, the most advanced and recent formulation, represented by alternative strategies, will be proposed. Particular emphasis will be placed on those ones involving new types of hydrogels, microparticles, nanoparticles, and liposomes, which are currently under investigation in preclinical studies. The potential application of particles and liposomes could foster the transition from natural lubricants to Drug Delivery Systems (DDSs) with lubricant features; transition which could provide more complete OA treatments, by simultaneously providing lubrication replacement and sustained release of different payloads and active agents directly at the joint level. Within each category, we will examine relevant preclinical studies, highlighting challenges and future prospects. [ABSTRACT FROM AUTHOR]

Blackcurrant is an anthocyanin-rich berry with proven antioxidant and photoprotective activity and emerging prebiotic potential, widely applied in cosmetic products. Hereby, highly efficient enzyme-assisted extraction of blackcurrant polyphenols was performed, giving extract with very high antioxidant activity. Obtained extract was characterized in terms of anthocyanin composition, incorporated into three different cosmetic formulations and subjected to Franz cell diffusion study. Experimental values obtained using cellulose acetate membrane for all four dominant anthocyanins (delphinidin 3-glucoside, delphinidin 3-rutinoside, cyanidin 3-glucoside and cyanidin 3-rutinoside) were successfully fitted with the Korsmeyer–Peppas diffusion model. Calculated effective diffusion coefficients were higher for hydrogel compared to oil-in-water cream gel and oil-in-water emulsion, whereas the highest value was determined for cyanidin 3-rutinoside. On the other hand, after a 72 h long experiment with transdermal skin diffusion model (Strat-M® membrane), no anthocyanins were detected in the receptor fluid, and only 0.5% of the initial quantity from the donor compartment was extracted from the membrane itself after experiment with hydrogel. Present study revealed that hydrogel is a suitable carrier system for the topical delivery of blackcurrant anthocyanins, while dermal and transdermal delivery of these molecules is very limited, which implies its applicability for treatments targeting skin surface (i.e., prebiotic, photoprotective). [ABSTRACT FROM AUTHOR]

This document is an editorial on the recent advances in hydrogels for biomedical applications. It discusses how the complexity of challenges in the biomedical field has driven the progress in designing and engineering advanced hydrogels. Hydrogels are biocompatible materials that can mimic the natural extracellular matrix and interact with biological environments, making them ideal for cellular processes and tissue regeneration. The editorial highlights specific contributions in the field, including the development of hydrogels for drug delivery in anticancer therapies, pH-triggered therapies, and multi-target therapies for wound healing and Candida albicans infection. It also includes two reviews on the use of hydrogels in cell transplantation and dental tissue engineering. Overall, the document showcases the potential of hydrogels in various biomedical applications. [Extracted from the article]

Background: This study explored the most suitable materials for incorporating cyano-phycocyanin (C-PC) into hydrogels, focusing on maintaining the C-PC's long-term structural integrity and stabilityNext, the release of C-PC from the hydrogels and its skin penetration were investigated. Methods: A series of 1% (w/w) C-PC hydrogels was prepared using various gelling agents and preservatives. Spectrophotometric measurements compared the amount of C-PC in the hydrogels to the initially added amount. After selecting the most suitable gelling agent and preservative, two C-PC hydrogels, with and without propylene glycol (PG) (Sigma-Aldrich, St. Louis, MO, USA), were produced for further testing. In vitro release studies utilized modified Franz-type diffusion cells, while ex vivo skin-permeation studies employed Bronaugh-type cells and human skin. Confocal laser scanning microscopy analyzed C-PC accumulation in the skin. Results: The findings demonstrated that sodium alginate (Sigma-Aldrich, St. Louis, MO, USA), hydroxyethyl cellulose (HEC) (Sigma-Aldrich, St. Louis, MO, USA), and SoligelTM (Givaudan, Vernier, Switzerland) are effective biopolymers for formulating hydrogels while maintaining C-PC stability. After 6 h, C-PC release from the hydrogel containing PG was approximately 10% or 728.07 (±19.35) μg/cm2, significantly higher than the nearly 7% or 531.44 (±26.81) μg/cm2 release from the hydrogel without PG (p < 0.05). The ex vivo qualitative skin-permeation study indicated that PG enhances C-PC penetration into the outermost skin layer. Conclusion: PG's ability to enhance the release of C-PC from the hydrogel, coupled with its capacity to modify the skin barrier ex vivo, facilitates the penetration of C-PC into the stratum corneum. [ABSTRACT FROM AUTHOR]

In order to remove Pb(II), Ni(II) and Mn(II) from aqueous solution, a lignin-based composite hydrogel (LS-g-P(AA-co-AM)/OMMT) was synthesized by free radical polymerization using sodium lignosulfonate (LS) and organic montmorillonite (OMMT) as raw materials. The obtained hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that the LS-g-P(AA-co-AM)/OMMT contains abundant C and O containing surface groups, which were favorable for the adsorption of Pb(II), Ni(II), Mn(II). The effects of adsorbent dosage, solution pH, temperature, initial concentration and time on hydrogel adsorption of Pb(II), Ni(II) and Mn(II) were investigated. The maximum adsorption amounts were 575.5, 326.67 and 282.82 mg/g, respectively. The adsorption process of heavy metal ions conforms to the pseudo-second-order kinetics and Langmuir model, which indicates that the adsorption of Pb(II), Ni(II) and Mn(II) by LS-g-P(AA-co-AM)/OMMT is a monolayer adsorption process dominated by chemical adsorption. The main adsorption mechanisms are ion exchange and coordination complexation. Conclusively, the prepared biomass adsorbent was proved as promising adsorbents for the removal of heavy metals. [ABSTRACT FROM AUTHOR]

As a member of soft matter, hydrogel is a new type of functional polymer material with a three-dimensional network structure. Due to the properties of high water content, fast swelling, good biocompatibility, and sensitive responsiveness to external stimuli, hydrogels have been widely used in various different fields. Starting from the common jellies and water-elf toys in life, this project gradually goes deep into 3D-printing technology hydrogels, deformable hydrogel, and memorizing-forgetting hydrogel based on thermal stimulation. For different audiences, we have popularized the knowledge of hydrogels at different levels, experienced the preparation and properties of different types of the hydrogels, and explained the related chemical principles, so as to improve the public chemical literacy. [ABSTRACT FROM AUTHOR]

Starch is a natural, biodegradable polymer that can be used to prepare hydrogels with various applications in food, pharmacy, medicine, agriculture, etc. In this study, a method of preparation using poly(methyl methacrylate) (PMMA) beads to control the porosity of starch hydrogels is proposed. The hydrogels are crosslinked with trisodium trimetaphosphate and dried in a vacuum oven. Results show that increasing the amount of PMMA beads result in higher porosity hydrogels ranging from ≈35% for hydrogels where no PMMA beads are used to ≈88% for hydrogels where the mass ratio of PMMA beads to starch is 10:1. Higher porosity hydrogels have a higher equilibrium water content and swelling degree, but lower mechanical properties. All hydrogels have a low solubility (<≈5%) and a high gel fraction (>≈90%) percentage. Upon degradation in α‐amylase at 37 °C, low porosity hydrogels (prepare with 0:1 and 1:10 PMMA beads:starch) degrade within 30 min, while high porosity hydrogels (prepare with 1:1 and 10:1 PMMA beads:starch) degrade within 3 weeks. The release of a dye that is incorporated into the hydrogel walls follows similar kinetics. Therefore, the use of PMMA beads is an efficient method to control starch hydrogel's porosity and properties. [ABSTRACT FROM AUTHOR]

The aim of this work is the derivation and examination of a material model, accounting for large elastic deformations, coupled with species diffusion and thermal effects. This chemo-thermo-mechanical material model shows three key aspects regarding its numerical formulation. Firstly, a multiplicative split of the deformation gradient into a mechanical, a swelling and a thermal part. Secondly, temperature-scaled gradients for a numerical design comprising symmetric tangents and, thirdly, dissipation potentials for the modelling of dissipative effects. Additionally, the derived general material model is specialised to thermoresponsive hydrogels to study its predictive capabilities for a relevant example material class. An appropriate finite element formulation is established and its implementation discussed. Numerical examples are investigated, including phase transition and stability phenomena, to verify the ability of the derived chemo-thermo-mechanical material model to predict relevant physical effects properly. We compare our results to established models in the literature and discuss emerging deviations. [ABSTRACT FROM AUTHOR]

The rise of antibiotic-resistant strains demands new alternatives in antibacterial treatment. Bacteriophages, with their precise host specificity and ability to target and eliminate bacteria safely, present a valuable option. Meanwhile, hydrogels, known for their excellent biodegradability and biocompatibility, serve as ideal carriers for bacteriophages. The combination of bacteriophages and hydrogels ensures heightened phage activity, concentration, controlled release, and strong antibacterial properties, making it a promising avenue for antibacterial treatment. This article provides a comprehensive review of different crosslinking methods for phage hydrogels, focusing on their application in treating infections caused by various drug-resistant bacteria and highlighting their effective antibacterial properties and controlled release capabilities. [ABSTRACT FROM AUTHOR]

Background/Objectives: Collagen–agarose hydrogel blends currently used in tracheal graft bioengineering contain relatively high concentrations of collagen to withstand mechanical stresses associated with native trachea function (e.g., breathing). Unfortunately, the high collagen content restricts effective cell infiltration into the hydrogel. In this study, we created an improved hydrogel blend with lower concentrations of collagen (<5 mg/mL) and characterized its capacity for fibroblast invasion and angiogenesis. Methods: Four collagen–agarose hydrogel blends were created: 1 mg/mL type 1 collagen (T1C) and 0.25% agarose, 1 mg/mL T1C and 0.125% agarose, 2 mg/mL T1C and 0.25% agarose, and 2 mg/mL T1C and 0.125% agarose. The hydrogel surface was seeded with fibroblasts, while both endothelial cells and fibroblasts (3:1 ratio) were mixed within the hydrogel matrix. We assessed early angiogenesis by observing fibroblast migration and endothelial cell morphology (elongation and branching) at 7 days. In addition, we performed immunostaining for alpha-smooth muscle actin (aSMA) and explored the gene expression of various angiogenic markers (including vascular endothelial growth factor; VEGF). Results: Gels with lower agarose concentrations (0.125%) with 1 or 2 mg/mL T1C were more effective in allowing early attachment and migration of surface-applied fibroblasts compared to gels with higher (0.25%) agarose concentrations. The low-agarose gels also allowed cells to quickly adopt a spread morphology and self-assemble into elongated structures indicative of early angiogenesis, while demonstrating positive immunostaining for aSMA and increased gene expression of VEGF by day 7. Conclusions: Hydrogel blends with collagen and low agarose concentrations may be effective in allowing early cellular infiltration and angiogenesis, making such gels a suitable cell substrate for use in the development of composite bioengineered tracheal grafts. The collagen–agarose hydrogel blend is meant to be cast around a three-dimensional (3D) printed polycaprolactone support structure and wrapped in porcine small intestine submucosa ECM to create an off-the-shelf bioengineered tracheal implant. [ABSTRACT FROM AUTHOR]