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Hybrid nanocomposite hydrogels consist of the homogeneous incorporation of nano‐objects in a hydrogel matrix. The latter, whether made of natural or synthetic materials, possesses a microporous, soft structure that makes it an ideal host for a variety of polymer and lipid‐based nano‐objects as well as metal‐ and silica‐based ones. By carefully choosing the composition and the proportions of the different constituents, hybrid hydrogels can display a wide array of properties, from simple enhancement of mechanical characteristics to specific bioactivity. This review aims to provide an overview of the state of the art in hybrid hydrogels highlighting key aspects that make them a promising choice for a variety of biomedical applications. Strategies for the preparation of hybrid hydrogels are discussed by covering the selection of individual components. The review will also explore the physico‐chemical and rheological characterization of these materials, which is essential for understanding their structure and function, ultimately satisfying specifications for the intended use. Successful examples of biomedical applications will also be presented, and the main challenges to be met will be discussed, with the aim of stimulating the research community to exploit the full potential of these materials. [ABSTRACT FROM AUTHOR]

Advancements in polymers have made significant contribution in diverse application‐oriented fields. The multidisciplinary application of polymers generates a range of strategies, which is applicable in a wide range of biomedicines. Polymeric compounds such as hydrogels have been explored globally as a potent biomaterial that can furnish essential attributes due to their three‐dimensional (3D) soft and highly hydrophilic polymeric network. These hydrogels have been used extensively in various applications due to their biocompatible, biodegradable, and biosorption nature. However, they have some limitations, owing to their soft nature, low mechanical properties, and unsatisfactory degradation profile. Therefore, there is a need to develop novel, stronger, and more durable hybrid hydrogels with enhanced biocompatible and multifunctional properties. The current review gives a broad spectrum of hybrid hydrogels with its importance and significance. Further, the review highlights the strategies of generation of hybrid hydrogels reinforced with nanomaterials, biomaterials, and nanobiocomposites along with their advantages and disadvantages. The review also features various applications of these hybrid hydrogels in the field of biomedicines, photocatalysis, agriculture, and food industry over the last 5 years. This review will give a comprehensive overview to researchers working in the field of hybrid hydrogels development. [ABSTRACT FROM AUTHOR]

Ying Yang,1– 3,* Bixia Zhou,1,2,* Min Li,4 Yishuai Sun,1,2 Xulei Jiang,1,2 Xinxin Zhou,1,2 Chengjun Hu,1,2 Dou Zhang,3 Hang Luo,3 Wuyuan Tan,1,2 Xinghua Yang,1,2 Shaorong Lei1,2 1Department of Plastic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 2National Clinical Research Center for Geriatric Disorders, Xiangya Hospital Central South University, Changsha, Hunan, People’s Republic of China; 3State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan, People’s Republic of China; 4Department of Oncology, Changsha Central Hospital, University of South China, Changsha, Hunan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Shaorong Lei, Department of Plastic Surgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, People’s Republic of China, Tel +86 73189753014, Email leishaorong@csu.edu.cn Xinghua Yang, Department of Plastic Surgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, People’s Republic of China, Tel +86 73189753014, Email yxhua8805@sina.comPurpose: The treatment of craniofacial bone defects caused by trauma, tumors, and infectious and degenerative diseases is a significant issue in current clinical practice. Following the rapid development of bone tissue engineering (BTE) in the last decade, bioactive scaffolds coupled with multifunctional properties are in high demand with regard to effective therapy for bone defects. Herein, an innovative bone scaffold consisting of GO/Cu nanoderivatives and GelMA-based organic-inorganic hybrids was reported for repairing full-thickness calvarial bone defect.Methods: In this study, motivated by the versatile biological functions of nanomaterials and synthetic hydrogels, copper nanoparticle (CuNP)-decorated graphene oxide (GO) nanosheets (GO/Cu) were combined with methacrylated gelatin (GelMA)-based organic-inorganic hybrids to construct porous bone scaffolds that mimic the extracellular matrix (ECM) of bone tissues by photocrosslinking. The material characterizations, in vitro cytocompatibility, macrophage polarization and osteogenesis of the biohybrid hydrogel scaffolds were investigated, and two different animal models (BALB/c mice and SD rats) were established to further confirm the in vivo neovascularization, macrophage recruitment, biocompatibility, biosafety and bone regenerative potential.Results: We found that GO/Cu-functionalized GelMA/β-TCP hydrogel scaffolds exhibited evidently promoted osteogenic activities, M2 type macrophage polarization, increased secretion of anti-inflammatory factors and excellent cytocompatibility, with favorable surface characteristics and sustainable release of Cu2+. Additionally, improved neovascularization, macrophage recruitment and tissue integration were found in mice implanted with the bioactive hydrogels. More importantly, the observations of microCT reconstruction and histological analysis in a calvarial bone defect model in rats treated with GO/Cu-incorporated hydrogel scaffolds demonstrated significantly increased bone morphometric values and newly formed bone tissues, indicating accelerated bone healing.Conclusion: Taken together, this BTE-based bone repair strategy provides a promising and feasible method for constructing multifunctional GO/Cu nanocomposite-incorporated biohybrid hydrogel scaffolds with facilitated osteogenesis, angiogenesis and immunoregulation in one system, with the optimization of material properties and biosafety, it thereby demonstrates great application potential for correcting craniofacial bone defects in future clinical scenarios. Keywords: nanomaterials, hybrid hydrogel, bone scaffolds, craniofacial bone defects, bone regeneration

Abstract This study investigates how dynamic fluctuations in matrix stiffness affect the behavior of cardiac fibroblasts (CFs) within a three-dimensional (3D) hydrogel environment. Using hybrid hydrogels with tunable stiffness, we created an in vitro model to mimic the varying stiffness of the cardiac microenvironment. By manipulating hydrogel stiffness, we examined CF responses, particularly the expression of α-smooth muscle actin (α-SMA), a marker of myofibroblast differentiation. Our findings reveal that increased matrix stiffness promotes the differentiation of CFs into myofibroblasts, while matrix softening reverses this process. Additionally, we identified the role of focal adhesions and integrin β1 in mediating stiffness-induced phenotypic switching. This study provides significant insights into the mechanobiology of cardiac fibrosis and suggests that modulating matrix stiffness could be a potential therapeutic strategy for treating cardiovascular diseases.

Amino acid-derived self-assembled nanofibers comprising supramolecular chiral hydrogels with unique physiochemical characteristics are highly demanded biomaterials for various biological applications. However, their narrow functionality often limits practical use, necessitating the development of biomaterials with multiple features within a single system. Herein, chiral co-assembled hybrid hydrogel systems termed LPH-EGCG and DPH-EGCG were constructed by co-assembling L/DPFEG gelators with epigallocatechin gallate (EGCG) followed by cross-linking with polyvinyl alcohol (PVA) and hyaluronic acid (HA). The developed hybrid hydrogels exhibit superior mechanical strength, self-healing capabilities, and adhesive properties, owing to synergistic non-covalent interactions. Integrating hydrophilic polymers enhances the system's capacity to demonstrate favorable swelling characteristics. Furthermore, the introduction of EGCG facilitated the hybrid gels to display notable antibacterial properties against both Gram-positive and Gram-negative bacterial strains, alongside showcasing strong antioxidant capabilities. In vitro investigation demonstrated enhanced cell adhesion and migration with the LPH-EGCG system in comparison to DPH-EGCG, thus emphasizing the promising prospects of these hybrid hydrogels in advanced tissue engineering applications. [ABSTRACT FROM AUTHOR]

This study investigates how dynamic fluctuations in matrix stiffness affect the behavior of cardiac fibroblasts (CFs) within a three-dimensional (3D) hydrogel environment. Using hybrid hydrogels with tunable stiffness, we created an in vitro model to mimic the varying stiffness of the cardiac microenvironment. By manipulating hydrogel stiffness, we examined CF responses, particularly the expression of α-smooth muscle actin (α-SMA), a marker of myofibroblast differentiation. Our findings reveal that increased matrix stiffness promotes the differentiation of CFs into myofibroblasts, while matrix softening reverses this process. Additionally, we identified the role of focal adhesions and integrin β1 in mediating stiffness-induced phenotypic switching. This study provides significant insights into the mechanobiology of cardiac fibrosis and suggests that modulating matrix stiffness could be a potential therapeutic strategy for treating cardiovascular diseases. [ABSTRACT FROM AUTHOR]

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Chen Yang,1 Jiaxing Lei,1 Ximeng Kang,1 Peipei Zhang,1 Shaohua Zheng,2 Qingqing Li,1 Jiye Zhang1 1School of Pharmacy, Health Science Center, Xi’an Jiaotong University, Xi’an, People’s Republic of China; 2The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, People’s Republic of ChinaCorrespondence: Qingqing Li; Jiye Zhang, School of Pharmacy, Health Science Center, Xi’an Jiaotong University, No. 76 Yanta Westroad, Xi’an, People’s Republic of China, Email liqingqing0217@mail.xjtu.edu.cn; zjy2011@mail.xjtu.edu.cnIntroduction: The effect of traditional treatment for melanoma is quite limited, especially for its recurrence. As the major components of yeast cell wall, chitin and β-glucan exhibit good immune activation effect and are promising candidates for adjuvant. Therefore, melanoma cell membrane (CM) and indocyanine green (ICG) was loaded in a chitin and β-glucan hybrid hydrogel to achieve an enhanced anti-melanoma therapy.Methods: The novel hybrid hydrogel was prepared, and its physicochemical properties were examined. Its effect towards melanoma prevention and treatment was evaluated via a melanoma-bearing mice model.Results: The CM-ICG-hybrid hydrogel was successfully prepared with excellent injectability, self-healing, drug loading, rheological, in vitro and in vivo photothermal stability, and retention properties. It also exhibited good cellular and in vivo safety profiles. In the primary melanoma mice model, it quickly ablated the in-situ melanoma, effectively inhibited the tumor growth, increased the survival rate of melanoma-bearing mice, and increased the level of IFN-γ and TNF-α. In the distal secondary melanoma model, it efficiently prevented the reoccurrence of melanoma and activated the memory T cells. In both models, a synergistic effect of photothermal therapy and immune therapy was found. The hydrogel effectively recruited CD3+ CD4+ T cells and CD3+ CD8+ T cells, inhibited the proliferation of melanoma cells, and induced the apoptosis of melanoma cells.Conclusion: The hybrid hydrogel was successfully prepared, and it showed excellent efficacy towards melanoma prevention and treatment due to its efficient tumor ablation and immune activation capability.Graphical Abstract: Keywords: chitin, β-glucan, hybrid hydrogel, melanoma cell membrane, photo thermotherapy, immunotherapy

A novel nanocomposite hydrogel with photothermal therapeutic properties, which could enhance the healing of surgical wounds, was developed. The composite comprises functionalized silica nanoparticles (FSNs) loaded with desferoxamine (DFO) as the core and a dexamethasone (Dex) filled hyaluronic acid–chitosan hydrogel (HA-CS) as the shell. Dex can effectively control inflammation at the wound site, and DFO is beneficial in proliferating the skin cells. The two drugs effectively promote wound healing at the surgical site. The aim of this approach is to demonstrate the hierarchical and continuous release of Dex and DFO from the FSNs@DFO-H@Dex system to reduce wound inflammation and promote healing. Furthermore, the controlled release of DFO can be achieved by controlling the near-infrared illumination. The composite nano hydrogel has a photothermal response, which accelerates wound healing by effectively reducing inflammation through the controlled release of drugs and regulating the immunological response of damaged skin tissue.

Lignocellulosic nanofibrils (LCNF) aerogels have a three-dimensional structure, with large specific surface area, low density, which is promising to be developed into a new type of adsorbent with high absorption capacity. However, LCNF aerogels have the problem of simultaneous oil and water adsorption. This high hydrophilicity directly leads to low adsorption efficiency in oil-water systems. This paper suggests a facile and economical method for the synthesis of biocompatible CE-LCNF aerogels using LCNF and Castor oil triglycidyl ether (CE) was successfully established. The use of LCNF enabled aerogels to possess remarkably uniform pore size and structural integrity, while the introduction of hydrophobic silica produced stable superhydrophobicity for more than 50 days at room temperature. These aerogels presented desirable hydrophobicity (131.6°), excellent oil adsorption capacity (62.5 g/g) and excellent selective sorption property, making them ideal absorbents for oil spill cleaning. The effects of ratios of LCNF to CE composition, temperatures and oil viscosity on the oil adsorption performance of aerogels were estimated. The results displayed that the aerogels had the maximum adsorption capacity at 25 °C. The pseudo-secondary model had higher validity in oil adsorption kinetic theories compared to the pseudo-first-order model. The CE-LCNF aerogels were excellent super-absorbents for oil removal. Moreover, the LCNF was renewable and nontoxic, which has the potential to promote environmental applications. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on the influence of the components of composition on the physicochemical properties of cross-linked poly(sodium acrylate)/sodium silicate hydrogels. The results of the rheological measurements showed that an increasing share of polyacrylate in the sample causes a shift of the cross-over point towards longer times and improves mechanical properties. In turn, increasing the share of sodium silicate has a positive effect on extending the fire insulation time (I). TG/DSC analysis indicated that if the sample contained more than 50 wt.% of polymer, the thermal decomposition was a three-stage process, while if the sample contained more water glass, the decomposition was two stage. UV-Vis measurements and SEM analysis confirmed, inter alia, that increasing the share of polyacrylate causes improvement of the optical parameters and homogeneity of the tested hydrogels. The presented results suggest that by controlling the share of the main components of the silicate–polymer hydrogels, it is possible to control their mechanical, optical and thermal properties. Multiplication of the layers or increasing their thickness improves their fire-retardant properties. [ABSTRACT FROM AUTHOR]

In this study, a new strategy was adopted for obtaining polymer/protein hybrid hydrogels with shape stability and tunable mechanical or rheological characteristics by using non-toxic procedures. A chemical network was created using a poly(vinyl alcohol)(PVA)/bovine serum albumin (BSA) mixture in aqueous solution in the presence of genipin and reduced glutathione (GSH). Then, a second physical network was formed through PVA after applying freezing/thawing cycles. In addition, the protein macromolecules formed intermolecular disulfide bridges in the presence of GSH. In these conditions, multiple crosslinked networks were obtained, determining the strengthening and stiffening into relatively tough porous hydrogels with tunable viscoelasticity and a self-healing ability. A SEM analysis evidenced the formation of networks with interconnected pores of sizes between 20 μm and 50 μm. The mechanical or rheological investigations showed that the hydrogels' strength and response in different conditions of deformation were influenced by the composition and crosslinking procedure. Thus, the dynamics of the hybrid hydrogels can be adjusted to mimic the viscoelastic properties of the native tissues. The dynamic water vapor-sorption ability, swelling behavior in an aqueous environment, and bioadhesive properties were also investigated and are discussed in this paper. The hybrid hydrogels with tunable viscoelasticity can be designed on request, and they are promising candidates for tissue engineering, bioinks, and wound dressing applications. [ABSTRACT FROM AUTHOR]

Abstract Bacterial infections can significantly impede wound healing and pose a serious threat to the patient’s life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing.

Amino acid-derived self-assembled nanofibers comprising supramolecular chiral hydrogels with unique physiochemical characteristics are highly demanded biomaterials for various biological applications. However, their narrow functionality often limits practical use, necessitating the development of biomaterials with multiple features within a single system. Herein, chiral co-assembled hybrid hydrogel systems termed LPH-EGCG and DPH-EGCG were constructed by co-assembling L/DPFEG gelators with epigallocatechin gallate (EGCG) followed by cross-linking with polyvinyl alcohol (PVA) and hyaluronic acid (HA). The developed hybrid hydrogels exhibit superior mechanical strength, self-healing capabilities, and adhesive properties, owing to synergistic non-covalent interactions. Integrating hydrophilic polymers enhances the system’s capacity to demonstrate favorable swelling characteristics. Furthermore, the introduction of EGCG facilitated the hybrid gels to display notable antibacterial properties against both Gram-positive and Gram-negative bacterial strains, alongside showcasing strong antioxidant capabilities. In vitro investigation demonstrated enhanced cell adhesion and migration with the LPH-EGCG system in comparison to DPH-EGCG, thus emphasizing the promising prospects of these hybrid hydrogels in advanced tissue engineering applications.

[Display omitted] • FeS nanoparticles were synthesized in situ in the GA hydrogels, yielding of FeS/GA hydrogels. • FeS/GA hydrogels induced bacterial death through the combination of ferroptosis damage and energy metabolism disruption. • FeS/GA hydrogels regulated macrophage responses in the inflammatory microenvironment. • FeS/GA hydrogels promoted the bacteria-infected diabetic wound healing in a simple, effective, and safe manner. Diabetic wound treatment faces great challenges in clinic. Staphylococcus aureus (S. aureus) is one of the most frequently isolated pathogens from the diabetic infections, which can severely impede wound healing time. Herein, ferrous sulfide (FeS) nanoparticles were fabricated through an in situ reaction between Fe2+ and S2− in glycyrrhizic acid (GA) solution. As the FeS nanoparticles aged, the solution gradually transformed into a gel, exhibiting excellent mechanical strength, injectability, and biocompatibility as a wound dressing. In addition to its own pharmacological effects, GA could act as the protector for FeS from oxidation of air. It also provided a weak acidic microenvironment, facilitating the pH-dependent dissolution reaction of FeS to release H 2 S and Fe2+. Notably, the effective antibacterial performance of the FeS/GA hydrogels towards S. aureus and multi-drug resistant S. aureus (MRSA) was achieved via the degradedly released Fe2+ and H 2 S through combination of ferroptosis damage and energy metabolism disruption. Moreover, FeS/GA hydrogels effectively modulated the proportion of M1/M2 macrophages, reduced the secretion of inflammatory cytokines, and significantly enhanced the proliferation and migration of fibroblasts in vitro. Importantly, in an MRSA-infected diabetic wound model, the FeS/GA hydrogels efficiently eradicated bacteria and regulated the inflammatory microenvironment, thereby promoting the diabetic wound repair. Overall, our study establishes a novel strategy for developing multifunctional hydrogels that serve as an effective therapeutic platform for managing bacteria-infected diabetic wounds. [ABSTRACT FROM AUTHOR]

The application of advanced oxidation processes (AOPs) based on sulfate radicals for degrading persistent organic pollutants faces challenges due to the inefficient activation of peroxydisulfate (PDS) oxidant. Herein, a composite CoFe2O4/MoS2‐xOy (CFM) catalyst consisting of CoFe2O4 nanoparticles uniformly dispersed on the nanosheets of oxygen‐incorporated MoS2 (MoS2‐xOy) with flower‐like morphology are fabricated through a facile two‐step hydrothermal method, which results in the enhanced activation of PDS and a highly efficient degradation of phenolic pollutants. The oxygen‐doping in MoS2‐xOy leads to unsaturated sulfur and active sites on the surface of MoS2 for accelerating the rate limiting step of FeIII/FeII reduction cycle in PDS‐CFM reaction. Aiming at the refractory organic pollutants in actual coking wastewater, CFM co‐catalyst is introduced into a hydrogel made up of polyvinyl alcohol (PVA) and coal‐tar pitch oxides (PO) to construct a multifunctional CFM@PO/PVA hydrogel. Upon hybrid CFM@PO/PVA, the coupling of the enhanced AOP with solar‐driven interfacial vapor generation (SIVG) technology contributes to the degradation efficiency, the removal rate of phenol in solution and the total organic carbon in coking wastewater can reach 98 % and 91 %, respectively. The integration of heterogeneous AOPs with SIVG system provides a feasible strategy for the eco‐friendly efficient purification of industrial wastewater. [ABSTRACT FROM AUTHOR]

Cartilage damage caused by trauma or osteoarthritis is a common joint disease that can increase the social and economic burden in society. Due to its avascular characteristics, the poor migration ability of chondrocytes, and a low number of progenitor cells, the self‐healing ability of cartilage defects has been significantly limited. Hydrogels have been developed into one of the most suitable biomaterials for the regeneration of cartilage because of its characteristics such as high‐water absorption, biodegradation, porosity, and biocompatibility similar to natural extracellular matrix. Therefore, the present review article presents a conceptual framework that summarizes the anatomical, molecular structure and biochemical properties of hyaline cartilage located in long bones: articular cartilage and growth plate. Moreover, the importance of preparation and application of hyaluronic acid – gelatin hydrogels for cartilage tissue engineering are included. Hydrogels possess benefits of stimulating the production of Agc1, Col2α1‐IIa, and SOX9, molecules important for the synthesis and composition of the extracellular matrix of cartilage. Accordingly, they are believed to be promising biomaterials of therapeutic alternatives to treat cartilage damage. [ABSTRACT FROM AUTHOR]

Abstract Background Excessive oxidative stress at the wound sites always leads to a prolonged healing and even causes chronic inflammatory wounds. Therefore, antioxidative dressings with multiple features are desired to improve wound healing performance. Herein, we fabricated a ROS-scavenging hybrid hydrogel by incorporating mussel-inspired fullerene nanocomposites (C60@PDA) into gelatin methacryloyl (GelMA) hydrogel. Results The developed C60@PDA/GelMA hydrogel showed a sustainable free radical scavenging ability, and eliminated ROS to protect cells against external oxidative stress damage. Besides, the hydrogel presented favorable cytocompatibility, hemocompatibility, and antibacterial ability in vitro. Furthermore, in a mouse full-thickness wound defect model, the in situ forming hybrid hydrogel accelerated wound closure by 38.5% and 42.9% on day 3 and day 7 over the control. Histological results demonstrated that hybrid hydrogels effectively enhanced wound healing on re-epithelialization, collagen deposition and angiogenesis. Conclusion Collectively, the C60@PDA/GelMA hydrogel could be a promising dressing for promoting cutaneous wound repair.

The mechanical properties of scaffolds play a vital role in regulating key cellular processes in tissue development and regeneration in the field of tissue engineering. Recently, scaffolding material design strategies leverage viscoelasticity to guide stem cells toward specific tissue regeneration. Herein, we designed and developed a viscoelastic Gel-PEG hybrid hydrogel with anisotropic morphology and mechanical properties using a gelatin and functionalized PEG (as a crosslinker) under a benign condition for tissue engineering application. The chemical crosslinking/grafting reaction was mainly involved between epoxide groups of PEG and available functional groups of gelatin. FTIR spectra revealed the hybrid nature of Gel-PEG hydrogel. The hybrid hydrogel showed good swelling behavior (water content > 600%), high porosity and pore interconnectivity suitable for tissue engineering application. Simple unidirectional freezing followed by a freeze-drying technique allowed the creation of structurally stable 3D anisotropic macroporous architecture that showed tissue-like elasticity and was capable of withstanding high deformation (50% strain) without being damaged. The tensile and compressive modulus of Gel-PEG hybrid hydrogel were found to be 0.863 MPa and 0.330 MPa, respectively, which are within the range of normal human articular cartilage. In-depth mechanical characterizations showed that the Gel-PEG hybrid hydrogel possessed natural-tissue-like mechanics such as non-linear and J-shaped stress-strain curves, stress softening effect, high fatigue resistance and stress relaxation response. A month-long hydrolytic degradation test revealed that the hydrogel gradually degraded in a homogeneous manner over time but maintained its structural stability and anisotropic mechanics. Overall, all these interesting features provide a potential opportunity for Gel-PEG hybrid hydrogel as a scaffold in a wide range of tissue engineering applications.

Bacterial infections can significantly impede wound healing and pose a serious threat to the patient’s life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing. [ABSTRACT FROM AUTHOR]

Environmentally friendly crosslinked carboxymethyl cellulose-based hybrid hydrogels (CCMC/OMMT) were prepared from a grafting of 2-acrylamide-2-methylpropane sulfonic acid (AMPS) onto CCMC and reinforced with Organo-Montmorillonite (OMMT) in this study as efficient adsorbents for methylene blue (MB). FTIR, SEM, XRD, EDS, XPS, and TGA techniques have been employed to investigate the composition and shape of the setup hydrogels. The MB adsorption ability of CCMC/OMMT was investigated concerning the initial MB concentration, pH, interaction time, and temperature. The capacity of CCMC/OMMT to adsorb on MB was 490.5 mg/g at 313.15 K and pH 7.0. Furthermore, the adsorption kinetics and isotherm were accurately predicted using the pseudo-second-order dynamic theory and Langmuir isotherm theory. The estimated thermal parameters ΔG0, ΔH0, and ΔS0 suggested that the molecules of MB binding on the CCMC/OMMT were spontaneous and endothermic. The procedures of sorption were facilitated by electrostatic attraction and hydrogen-bonding interaction. Additionally, all manufactured hydrogels were reusable for MB removal. As a result, CCMC/OMMT can be used as environmentally safe, productive, and washable stuff for MB in sewage treatment. [ABSTRACT FROM AUTHOR]

Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas–Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer–Peppas model. According to the present study, the porous membranes containing 40–60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions. [ABSTRACT FROM AUTHOR]

The mechanical properties of scaffolds play a vital role in regulating key cellular processes in tissue development and regeneration in the field of tissue engineering. Recently, scaffolding material design strategies leverage viscoelasticity to guide stem cells toward specific tissue regeneration. Herein, we designed and developed a viscoelastic Gel-PEG hybrid hydrogel with anisotropic morphology and mechanical properties using a gelatin and functionalized PEG (as a crosslinker) under a benign condition for tissue engineering application. The chemical crosslinking/grafting reaction was mainly involved between epoxide groups of PEG and available functional groups of gelatin. FTIR spectra revealed the hybrid nature of Gel-PEG hydrogel. The hybrid hydrogel showed good swelling behavior (water content > 600%), high porosity and pore interconnectivity suitable for tissue engineering application. Simple unidirectional freezing followed by a freeze-drying technique allowed the creation of structurally stable 3D anisotropic macroporous architecture that showed tissue-like elasticity and was capable of withstanding high deformation (50% strain) without being damaged. The tensile and compressive modulus of Gel-PEG hybrid hydrogel were found to be 0.863 MPa and 0.330 MPa, respectively, which are within the range of normal human articular cartilage. In-depth mechanical characterizations showed that the Gel-PEG hybrid hydrogel possessed natural-tissue-like mechanics such as non-linear and J-shaped stress-strain curves, stress softening effect, high fatigue resistance and stress relaxation response. A month-long hydrolytic degradation test revealed that the hydrogel gradually degraded in a homogeneous manner over time but maintained its structural stability and anisotropic mechanics. Overall, all these interesting features provide a potential opportunity for Gel-PEG hybrid hydrogel as a scaffold in a wide range of tissue engineering applications. [ABSTRACT FROM AUTHOR]

Perfluorooctanesulfonic acid (PFOS) is classified as a chemically stable anthropogenic micropollutant has been found contaminating most of the water environment worldwide. Thus, this study focused on designing a new hybrid hydrogel adsorbent based on combination of biopolymers such as sodium alginate, β-cyclodextrin and multi-walled carbon nanotubes to resolve the problem. The batch adsorption experiments were studied to investigate the adsorption efficacy for PFOS from the aqueous environment with several adsorption conditions such as adsorbent dosage, initial concentration, pH and contact time. The optimum operative variables that induced a delicate adsorption capacity of 91.6% for PFOS removal were 1000 mg of adsorbent dosage, 10 mg/L of PFOS solution, pH 3, and a contact time of 45 min. Kinetic and isotherm model were utilized to emphasized the equilibrium adsorption data and the perfectly fitted kinetic modelling is pseudo-second-order (R2 = 0.976) while adsorption isotherm simulated by Langmuir model (R2 = 0.918). Furthermore, the fabricated hybrid hydrogel bead could be reused multiple times without an obvious decrease in the removal efficiency. Hence, this work provides a feasible approach in developing a hybrid hydrogel adsorbent that could be used as high-performance adsorbent for PFOS remediation in the water treatment application. [ABSTRACT FROM AUTHOR]

Background: Excessive oxidative stress at the wound sites always leads to a prolonged healing and even causes chronic inflammatory wounds. Therefore, antioxidative dressings with multiple features are desired to improve wound healing performance. Herein, we fabricated a ROS-scavenging hybrid hydrogel by incorporating mussel-inspired fullerene nanocomposites (C60@PDA) into gelatin methacryloyl (GelMA) hydrogel. Results: The developed C60@PDA/GelMA hydrogel showed a sustainable free radical scavenging ability, and eliminated ROS to protect cells against external oxidative stress damage. Besides, the hydrogel presented favorable cytocompatibility, hemocompatibility, and antibacterial ability in vitro. Furthermore, in a mouse full-thickness wound defect model, the in situ forming hybrid hydrogel accelerated wound closure by 38.5% and 42.9% on day 3 and day 7 over the control. Histological results demonstrated that hybrid hydrogels effectively enhanced wound healing on re-epithelialization, collagen deposition and angiogenesis. Conclusion: Collectively, the C60@PDA/GelMA hydrogel could be a promising dressing for promoting cutaneous wound repair. [ABSTRACT FROM AUTHOR]

The main challenge of extrusion 3D bioprinting is the development of bioinks with the desired rheological and mechanical performance and biocompatibility to create complex and patient-specific scaffolds in a repeatable and accurate manner. This study aims to introduce non-synthetic bioinks based on alginate (Alg) incorporated with various concentrations of silk nanofibrils (SNF, 1, 2, and 3 wt.%) and optimize their properties for soft tissue engineering. Alg-SNF inks demonstrated a high degree of shear-thinning with reversible stress softening behavior contributing to extrusion in pre-designed shapes. In addition, our results confirmed the good interaction between SNFs and alginate matrix resulted in significantly improved mechanical and biological characteristics and controlled degradation rate. Noticeably, the addition of 2 wt.% SNF improved the compressive strength (2.2 times), tensile strength (5 times), and elastic modulus (3 times) of alginate. In addition, reinforcing 3D-printed alginate with 2 wt.% SNF resulted in increased cell viability (1.5 times) and proliferation (5.6 times) after 5 days of culturing. In summary, our study highlights the favorable rheological and mechanical performances, degradation rate, swelling, and biocompatibility of Alg-2SNF ink containing 2 wt.% SNF for extrusion-based bioprinting. [ABSTRACT FROM AUTHOR]

A novel thermoresponsive magnetic hydrogel microparticle system was obtained by magnetic nanoparticles (MNPs) combined with poly(N-vinylcaprolactam)-g-galactosylated chitosan (GC) (PNVCL-g-GC) hybrid hydrogel. Fe3O4@PNVCL-g-GC microparticles (MPs) were synthesized by the suspension crosslinking method and the Fe3O4 MNPs were successfully encapsulated in the hybrid hydrogel with good magnetism. Fe3O4@PNVCL-g-GC MPs were characterized by ATR-FTIR, LCST, SEM-EDAX, particle size, zeta potential, TGA and VSM analyses. The size distribution of the spherical Fe3O4@PNVCL-g-GC MPs at room temperature was in the range of 390-530 nm, while it was measured as ∼220–340 nm above the LCST. The cytocompatibility and hemocompatibility of the Fe3O4@PNVCL-g-GC MPs were confirmed by in vitro ISO analyses. In conclusion, biocompatible, temperature- and magnetic-responsive small-size Fe3O4@PNVCL-g-GC MPs with enhanced mechanical stability were developed which could have the potential for a variety of biomedical applications such as controlled release systems, in situ bioactive agents carrier, and anti-cancer therapy in the future. [ABSTRACT FROM AUTHOR]

Fast and efficient removal of organic dyes from industrial wastewater by practical and cost-effective adsorption method has been in the spotlight. Herein, lignosulfonate-based hybrid hydrogel adsorbents (HPAS) were one-pot synthesized via cross-linking reaction with lignosulfonate amine, hyperbranched polyamide amine, and polyethylene glycol diglycidyl ether, then were characterized by FTIR, XPS, and SEM measurements. The adsorption capacity of HPAS for separate organic dyes and metallic ion were further studied. HPAS with hierarchical porous structures showed ultra-high capacity for dye removal, especially for Congo red (CR). The actual maximum adsorption capacity of CR can reach 5120 mg/g, when the initial concentration of CR is 6000 mg/L, natural pH, temperature is 298 K, and the amount of adsorbent HPAS-4 is 0.8 g/L. Simultaneously, HPAS-4 also showed a relatively strong adsorption performance for Cu(II); the maximum uptake capacity was obtained at 249 mg/g (initial Cu(II) concentration = 100 mg/L). After 5 adsorption–desorption cycles, HPAS-4 still maintains a high adsorption capacity for CR and Cu(II). The CR and Cu(II) adsorption mechanisms by HPAS were further validated using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The adsorption of CR and Cu(II) by HPAS was a spontaneous endothermic process, which conforms to the pseudo-second-order kinetic model and Langmuir adsorption model. The key mechanism of CR adsorption process is H-bond interactions due to abundant N and O atoms in HPAS accompanied with electrostatic attraction and π-π stacking interaction. The adsorption of Cu(II) on HPAS is mainly determined by the complexation/chelation accompanied with precipitation of copper derivatives on HPAS. The results of this study provide a new method for the preparation of high-performance biomass-based adsorbents in the field of wastewater treatment. [ABSTRACT FROM AUTHOR]

Nanozymes have become promising alternative antibacterial agents for bacteria-infected wounds. In this study, fucoidan-confined gold nanoparticles (Fuc@AuNPs) are developed by in situ reduction, and stabilized by sulfate groups of fucoidan. Fuc@AuNPs exhibit pH-responsive catalytic activity that can mimic oxidase (OXD) under acidic bacterial infection conditions and mimic superoxide dismutase (SOD) under normal physiological conditions. The OXD-like catalytic activity of Fuc@AuNPs generates active singlet oxygen (1O 2), exhibiting effective antibacterial properties against both Gram-negative E. coli and Gram-positive S. aureus. Fuc@AuNPs and aldehyde grafted saponin incorporate with chitosan to form a hybrid hydrogel. This hydrogel exhibits superior mechanical, adhesive, and self-healing properties due to electrostatic complex coacervation networks and dynamic covalent Schiff base reactions. Animal experiments show that the hydrogel aids S. aureus -infected skin wound healing by reducing bacterial infection and promoting granulation tissue formation without causing excessive ROS-induced inflammation. This study presents the design of multifunctional nanozymes and bioactive hydrogels as a promising wound healing dressing for biomedical applications. [ABSTRACT FROM AUTHOR]

Partial liver resection is an established treatment for hepatic disorders. However, surgical bleeding, intra-abdominal adhesion and rapid liver regeneration are still major challenges after partial liver resection, associated with morbidity and mortality. Herein, a biomimetic hybrid hydrogel, composed of oxidized hyaluronic acid, glycol chitosan and MenSCs-derived conditioned medium (CM), is presented to address these issues. The hybrid hydrogel is formed through reversible Schiff base, and possesses injectability and self-healing capability. Moreover, hybrid hydrogel exhibits the capabilities of hemostasis, anti-infection, tissue adhesion and controllable release of cargoes. Based on in vivo studies of the multifunctional hybrid hydrogel, it is demonstrated that acute bleeding in partial liver resection can be ceased immediately by virtue of the hemostasis features of hybrid hydrogel. Also, a significant reduction of intra-abdominal adhesion is confirmed in hybrid hydrogel-treated resection surface. Furthermore, upon the treatment of hybrid hydrogel, hepatic cell proliferation and tissue regeneration can be significantly improved due to the controllably released cytokines from MenSCs-derived CM, exerting the effects of mitogenesis and anti-inflammation in vivo. Thus, the biomimetic hybrid hydrogel can be a promising candidate with great potential for application in partial liver resection.

Polyvinyl alcohol (PVA) hydrogels were enhanced mechanically through the addition of lignin-rich nanocellulose (LCN), soluble ash (SA) and montmorillonite (MMT) for dye removal. The hybrid hydrogels reinforced with 33.3 wt% of LCN had a 163.0% increase in storage modulus as compared to the PVA/0LCN-33.3SM hydrogel. LCN can be added to the PVA hydrogel to alter its rheological properties. Additionally, hybrid hydrogels were highly efficient in removing methylene blue from wastewater, which was attributed to the synergistic effects of the PVA matrix supporting embedded LCN, MMT, and SA. The adsorption time (0–90 min) showed that the hydrogels containing MMT and SA had high removal efficiency, and the adsorption of methylene blue (MB) by PVA/20LCN-13.3SM was greater than 95.7% at 30°C. It was found that MB efficiency decreased with a high MMT and SA content. Our study provided a new method for the fabrication of polymers-based eco-friendly, low-cost and robust physical hydrogels for the MB removal.

Natural organic matter, including humic substances (HS), comprises complex secondary structures with no defined covalent chemical bonds and stabilized by inter- and intra-molecular interactions, such as hydrogen bonding, Van der Waal's forces, and pi-pi interactions. The latest view describes HS aggregates as a hydrogel-like structure comprised by a hydrophobic core of aromatic residues surrounded by polar and amphiphilic molecules akin a self-assembled soft material. A different view is based on the classification of this material as either mass or surface fractals. The former is intended as made by the clustering of macromolecules generating dendritic networks, while the latter have been modelled in terms of a solvent-impenetrable core surrounded by a layer of lyophilic material. This study reviews the evolution of the increasingly refined models that appeared in the literature, all capable to describing the physicochemical properties of HS. All the models are critically examined and revisited in terms of their ability to provide key information on the structural organization of HS. Understanding how the molecular association pathway influences aggregation of HS also provides a key acknowledgment of their role in the environment. [ABSTRACT FROM AUTHOR]

This paper reports new physical hydrogels obtained by the freezing/thawing method. They include pullulan (PULL) and poly(vinyl alcohol) (PVA) as polymers, bovine serum albumin (BSA) as protein, and a tripeptide, reduced glutathione (GSH). In addition, a sample containing PULL/PVA and lysozyme was obtained in similar conditions. SEM analysis evidenced the formation of networks with porous structure. The average pore size was found to be between 15.7 μm and 24.5 μm. All samples exhibited viscoelastic behavior typical to networks, the hydrogel strength being influenced by the protein content. Infrared spectroscopy analysis revealed the presence of intermolecular hydrogen bonds and hydrophobic interactions (more pronounced for BSA content between 30% and 70%). The swelling kinetics investigated in buffer solution (pH = 7.4) at 37 °C evidenced a quasi-Fickian diffusion for all samples. The hydrogels were loaded with neomycin trisulfate salt hydrate (taken as a model drug), and the optimum formulations (samples containing 10–30% BSA or 2% lysozyme) proved a sustained drug release over 480 min in simulated physiological conditions. The experimental data were analyzed using different kinetic models in order to investigate the drug release mechanism. Among them, the semi-empirical Korsmeyer–Peppas and Peppas–Sahlin models were suitable to describe in vitro drug release mechanism of neomycin sulfate from the investigated hybrid hydrogels. The structural, viscoelastic, and swelling properties of PULL/PVA/protein hybrid hydrogels are influenced by their composition and preparation conditions, and they represent important factors for in vitro drug release behavior. [ABSTRACT FROM AUTHOR]

The generation of 3D‐bioprintable and biocompatible hydrogels based on elastin and hyaluronic acid is described. The procedure is based on a biocompatible click reaction between maleimide and thiol for the final crosslinking, employable with living cells due to fast kinetics and absence of side products. To this end, both α‐elastin and hyaluronic acid were functionalized with linkers ending with maleimide groups, at controlled functionalization intensities, and crosslinked with a dithiol−PEG linker. Varying the equivalents of the three reagents, four different hydrogels were obtained and their biocompatibility, swelling capacity and printability were tested. Biological experiments were performed with human lung fibroblast, human bronchial epithelial and human endothelial cell lines cultured in the hydrogels. Fibroblasts and epithelial cells can survive and proliferate. Epithelial cells showed an increased expression of CD44 and integrin αvβ3. Gene expression analysis revealed up‐regulation of metalloproteinases both in normal fibroblast and epithelial cells. [ABSTRACT FROM AUTHOR]

In the present paper, biodegradable hybrid hydrogels were prepared by using chitosan as a natural polymer and polyurethane containing azomethine as a synthetic polymer for the drug delivery application for 5‐fluorouracil. The fabricated hydrogels were characterized via FT‐IR and SEM analysis. Besides, the thermal, mechanical, and wettability properties, water uptake, biodegradation, protein absorption, drug loading, and release behaviors of the hybrid hydrogels were studied. The obtained results indicated that the fabricated hybrid hydrogels have exhibited good mechanical, hydrophilic, water uptake, and biodegradation behaviors. The hybrid hydrogels also showed 50% drug release amounts and they could be a good candidate for the controlled delivery of 5‐FU due to these properties. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) bioprinting allows the production of artificial 3D cellular microenvironments thanks to the controlled spatial deposition of bioinks. Proper bioink characterization is required to achieve the essential characteristics of printability and biocompatibility for 3D bioprinting. In this work, a protocol to standardize the experimental characterization of a new bioink is proposed. A functionalized hydrogel based on gelatin and chitosan was used. The protocol was divided into three steps: pre-printing, 3D bioprinting, and post-printing. For the pre-printing step, the hydrogel formulation and its repeatability were evaluated. For the 3D-bioprinting step, the hydrogel-printability performance was assessed through qualitative and quantitative tests. Finally, for the post-printing step, the hydrogel biocompatibility was investigated using UMR-106 cells. The hydrogel was suitable for printing grids with good resolution from 4 h after the cross-linker addition. To guarantee a constant printing pressure, it was necessary to set the extruder to 37 °C. Furthermore, the hydrogel was shown to be a valid biomaterial for the UMR-106 cells' growth. However, fragmentation of the constructs appeared after 14 days, probably due to the negative osteosarcoma-cell interference. The protocol that we describe here denotes a strong approach to bioink characterization to improve standardization for future biomaterial screening and development. [ABSTRACT FROM AUTHOR]

Adsorption-based research toward biodegradable polymers has received much attention in recent years due to environmental concerns. Polysaccharides in this domain are interesting starting materials for the preparation of novel adsorbents. In this work, novel type of biopolymer-based hybrid hydrogel (HH) was designed for removal of Cr (VI) ion from aqueous solution. Polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), acrylamide-grafted native starch (Coccinia abyssinica) (ST-g-AAm), chitosan (CS), and graphene oxide (GO) were used to prepare PVA/PVP/ST-g-AAm/CS/GO HH. Physiochemical properties of freeze-dried hydrogel were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and swelling tests. Adsorptions of Cr (VI) ion onto the hydrogel as functions of initial Cr (VI) ion concentration, pH, time, hydrogel dose, and temperature have been studied. The adsorption data agree with Langmuir isotherm at 25°C and follow pseudo-second-order kinetic model at pH of 2. The maximum adsorption capacity of the hydrogel was 93 mg g−1. The obtained negative standard Gibb's free energy (∆G° = – 1.120 kJ mol−1) and negative enthalpy (∆H° = – 2.360 kJ mol−1) reveal the spontaneity and exothermic nature of Cr (VI) ion adsorption. Moreover, the adsorption thermodynamics shows enthalpically favoring host–guest complexion along with decrease in entropy. [ABSTRACT FROM AUTHOR]

Water pollution issues, particularly those caused by heavy metal ions, have been significantly growing. This paper combined biopolymers such as sodium alginate (SA) and β-cyclodextrin (β-CD) to improve adsorption performance with the help of calcium ion as the cross-linked agent. Moreover, the addition of carbon nanotubes (CNTs) into the hybrid hydrogel matrix was examined. The adsorption of nickel(II) was thoroughly compared between pristine sodium alginate/β-cyclodextrin (SA-β-CD) and sodium alginate/β-cyclodextrin immobilized carbon nanotubes (SA-β-CD/CNTs) hydrogel. Both hydrogels were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectral analysis, field emission scanning electron microscopy (FESEM), electron dispersive spectroscopy (EDX), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) surface area analysis. The results showed SA-β-CD/CNTs hydrogel exhibits excellent thermal stability, high specific surface area and large porosity compared with SA-β-CD hydrogel. Batch experiments were performed to study the effect of several adsorptive variables such as initial concentration, pH, contact time and temperature. The adsorption performance of the prepared SA-β-CD/CNTs hydrogel was comprehensively reported with maximum percentage removal of up to 79.86% for SA-β-CD/CNTs and 69.54% for SA-β-CD. The optimum adsorption conditions were reported when the concentration of Ni(II) solution was maintained at 100 ppm, pH 5, 303 K, and contacted for 120 min with a 1000 mg dosage. The Freundlich isotherm and pseudo-second order kinetic model are the best fits to describe the adsorption behavior. A thermodynamic study was also performed. The probable interaction mechanisms that enable the successful binding of Ni(II) on hydrogels, including electrostatic attraction, ion exchange, surface complexation, coordination binding and host–guest interaction between the cationic sites of Ni(II) on both SA-β-CD and SA-β-CD/CNTs hydrogel during the adsorption process, were discussed. The regeneration study also revealed the high efficiency of SA-β-CD/CNTs hydrogel on four successive cycles compared with SA-β-CD hydrogel. Therefore, this work signifies SA-β-CD/CNTs hydrogel has great potential to remove Ni(II) from an aqueous environment compared with SA-β-CD hydrogel. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA), an FDA-approved natural polymer and important component of the extracellular matrix (ECM), has been widely used to develop hydrogels for cartilage regeneration. However, HA hydrogels often exhibit poor mechanical properties and unsuitable degradability, limiting their capability to support cell growth in cartilage. To overcome these challenges, this study modifies HA with a silica precursor and the coupling agent (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) to develop a monophasic organic-inorganic hybrid HA-silica hydrogel. In this system, the inorganic silicate and organic HA components interpenetrate and bond covalently at the molecular level. The HA-silica hybrid hydrogel achieves a compressive modulus of 143 kPa at the highest GPTMS/HA molar ratio of 400. Additionally, in vitro cell studies show that these hybrid hydrogels have no cytotoxicity against MC3T3-E1 and ATDC-5 cells. Cell viability and morphology tests further confirm excellent cell adhesion on the hybrid scaffold. These results indicate that the developed HA-silica hybrid hydrogel is a suitable candidate for cartilage regeneration applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Gelatin-based hydrogels are highly desirable biomaterials for use in wound dressing, drug delivery, and extracellular matrix components due to their biocompatibility and biodegradability. However, insufficient and uncontrollable mechanical properties and degradation are the major obstacles to their application in medical materials. Herein, we present a simple but efficient strategy for a novel hydrogel by incorporating the synthetic hydrogel monomer polyethylene glycol diacrylate (PEGDA, offering high mechanical stability) into a biological hydrogel compound (gelatin) to provide stable mechanical properties and biocompatibility at the resulting hybrid hydrogel. In the present work, PEGDA/gelatin hybrid hydrogels were prepared by electron irradiation as a reagent-free crosslinking technology and without using chemical crosslinkers, which carry the risk of releasing toxic byproducts into the material. The viscoelasticity, swelling behavior, thermal stability, and molecular structure of synthesized hybrid hydrogels of different compound ratios and irradiation doses were investigated. Compared with the pure gelatin hydrogel, 21/9 wt./wt. % PEGDA/gelatin hydrogels at 6 kGy exhibited approximately up to 1078% higher storage modulus than a pure gelatin hydrogel, and furthermore, it turned out that the mechanical stability increased with increasing irradiation dose. The chemical structure of the hybrid hydrogels was analyzed by Fourier-transform infrared (FTIR) spectroscopy, and it was confirmed that both compounds, PEGDA and gelatin, were equally present. Scanning electron microscopy images of the samples showed fracture patterns that confirmed the findings of viscoelasticity increasing with gelatin concentration. Infrared microspectroscopy images showed that gelatin and PEGDA polymer fractions were homogeneously mixed and a uniform hybrid material was obtained after electron beam synthesis. In short, this study demonstrates that both the presence of PEGDA improved the material properties of PEGDA/gelatin hybrid hydrogels and the resulting properties are fine-tuned by varying the irradiation dose and PEGDA/gelatin concentration.

[Display omitted] • A hydrogel with interpenetrated network is prepared by PVA, starch and CNT. • It shows a wide adsorption in solar spectrum and excellent light-to-heat conversion. • It exhibits a very high evaporation rate of 2.44 kg m−2h−1 under 1 Sun irradiation. • Evaporator can precisely adjust the water state and reduce the evaporation enthalpy. • It removes heavy metal ions, organic dyes and kill bacterial in the wastewater. Solar evaporation which ultilizes the sustainable solar energy for freshwater production from waste or saline water is one of the most attractive technologies to simultaneously address energy and freshwater crisis. Nevertheless, high energy consumption of water-vapor transformation greatly restricts the practical applications of solar-driven water purification. Herein, we report hybrid hydrogels formed by introducing biomass, starch, and carbon nanotube into hydrophilic polyvinyl alcohol in a cost-effective route, used as multifunctional evaporators. The interpenetrating network has good hydrophilicity, fast water transport and adjustable state of water molecules, which reduces the enthalpy of water vaporization to promote the evaporation process. Thus, the obtained hydrogel evaporator possesses an evaporation rate of 2.44 kg m−2h−1 with 95% efficiency under one-sun, and is capable of producing clean water from various types of wastewater, including salty, acidic, alkaline and organic polluted water, with long-term durability and stability. It also presents excellent antibacterial, salt resistance and self-cleaning capabilities, suitable for practical applications. More notably, with abundant OH groups from starch, the hybrid hydrogel can effectively adsorb heavy metal ions and organic dyes via formation of chelating and hydrogen bonds. Therefore, this work provides a new approach for portable and cost-effective solar-driven wastewater purification. [ABSTRACT FROM AUTHOR]

In this work, hybrid hydrogels were synthesized with the inclusion of two types of clay materials that are considered industrial waste: red mud (RM) and ferrosilicomanganese fines (FeSiMn). These solid waste materials were characterized by studying their particle size and chemical composition, which are two key variables for their application in the synthesis of hybrid hydrogels. The morphology imaged by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showed, in the case of RM, heterogeneous size and shape particles, with 73% of the particles having lengths of less than 5 μm. On the other hand, FeSiMn had particles with a circular morphology of nanometric sizes. Regarding the synthesis of the hybrid hydrogels, it was determined that the incorporation of small percentages (0.1%) of the inorganic phases improved the capacity of the materials to absorb water (swelling indices of 1678% and 1597% for the RM and FeSiMn hydrogels, respectively) compared to the conventional polyacrylamide hydrogel (1119%). An improvement in Vickers microhardness and storage modulus (G′) was also observed: the hybrid with 10% RM presented a G′, 50 times higher than conventional hydrogel. The results show the merit of RM and FeSiMn in improving the properties of hydrogels. [ABSTRACT FROM AUTHOR]

Background and Objective: cactus pear (Opuntia stricta) is known as a source of polysaccharide compounds (mucilage) that can trap water by the three-dimensional network. Hydrogels are three-dimensional polymer networks with cross-links that can absorb large amounts of water. In recent years, the use of these compounds as a thickening or gelling agent has increased. In these systems, whey protein hydrogel due to its high nutritional value, good functional properties, and biocompatibility has attracted the attention of the food industry. In this study, the production of new hydrogels (hybrid hydrogels) in combination with a polysaccharide component for improving the functional properties of whey protein was investigated. The purpose of this study was to evaluate the behavior of Whey Protein Isolated-Opuntia hybrid hydrogels in terms of rheological behavior and textural properties as a subordinate of protein and polysaccharide concentrations. Materials and Methods: Opuntia fruit powder was prepared from the fruit pulp by a hot air dryer. To prepare the main/final mixture of the hydrogel, two hydrogel bases including Opuntia pulp hydrogel (Op) (20% w/w) and whey protein isolate hydrogel (W) (15% w/w) were mixed in different ratios (W/Op: 80-20, 70-30, 60-40, 50-50) by an electric mixer at low speed for 1 minute. Finally, textural properties including (viscosity, consistency, hardness, adhesiveness), water holding capacity, swelling ratio, and rheological properties were tested. Data were analyzed using SAS software and the mean values were compared using Duncan's multiple range test at the 5% level. Results:Increasing ratio of Opuntia hydrogel to Whey protein hydrogel caused a significant increase in Viscosity, Consistency, Hardness, and Adhesiveness of hybrid hydrogels (W-Op H) compared to protein control (Whey protein) (p≤0.05). Also, Water Holding Capacity and Swelling ratio increased with increasing the ratio of Opuntia hydrogel in the samples (p≤0.05). Opuntia and Whey Protein Isolate hydrogel had the highest (694.71± 42.89 %) and lowest (340.22 ± 7.19 %) swelling ratios among the other samples, respectively. On the other hand, the addition of Opuntia hydrogel to Whey Protein Isolate hydrogel enhanced the viscoelastic behavior of the mixture, so that with increasing Opuntia hydrogel ratio, the storage and loss modulus was increased. The loss factor of hydrogel samples was between 0.24-0.36, which can be obtained as semi-gel material and the elastic behavior was more dominant than the viscose behavior. Conclusion: hybrid hydrogel (W/Op: 60-40) due to its highest viscosity, maximum water holding capacity, and swelling ratio, as well as the presence of appropriate rheological behavior, was suggested as the best sample for thickening agent and texture improvement in food products such as ice cream, sauces, meat products, dairy products, Tofu, Noodles, etc. [ABSTRACT FROM AUTHOR]

Hydrogel is a 3D framework of hydrophilic polymeric material that quickly absorbs and retains a huge amount of water (or other fluid) and offers versatile functionality. A series of unique carboxymethyl cellulose/Xanthan gum/polyvinyl alcohol (CXP) blended hydrogels, containing both the natural and synthetic polymers, were prepared by following the blending and casting approach. The polymers were incorporated through chemical crosslinking by tetraethyl orthosilicate (TEOS). The fabricated hydrogels showed all required features: non-toxicity, biocompatibility, and improved mechanical strength. The addition and variation in TEOS (crosslinker) significantly impacted the key characteristics of CXP hydrogel. The scanning electron microscopy (SEM) images showed the porous structure and indicated that the pore's size and intensity were reduced with the surge in TEOS content. Fourier transform infrared spectroscopy (FTIR) results confirmed the successful incorporation of various polymeric strands through crosslinking by TEOS. The thermogravimetric analysis (TGA) highlighted the greater stability of all the hydrogels over high temperatures. The crosslinked hydrogel displayed higher thermal resilience than the uncross-linked one. The differential thermal analysis (DTA) also confirmed that the addition of TEOS content drastically enhanced the thermal endurance of crosslinked hydrogels in comparison with the neat hydrogel. All the specimens exhibited good swelling ability in distilled water during the swelling studies. This study also reflected that the addition of crosslinker in a limited amount (50 µL) has significantly enhanced the swelling but further increase in concentration hindered the water uptake. The swelling response of blends towards pH revealed low swelling of films in acidic and basic pH, but maximal swelling in neutral media. This unique pH response of hydrogels at neutral pH along with the biocompatibility made them suitable for injectable managed drug carrier. [ABSTRACT FROM AUTHOR]