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Electrochemical sensors are among the most promising technologies for biomarker research, with outstanding sensitivity, selectivity, and rapid response capabilities that make them important in medical diagnostics and prognosis. Recently, hydrogels have gained attention in the domain of electrochemical biosensors because of their superior biocompatibility, excellent adhesion, and ability to form conformal contact with diverse surfaces. These features provide distinct advantages, particularly in the advancement of wearable biosensors. This review examines the contemporary utilization of hydrogels in electrochemical sensing, explores strategies for optimization and prospective development trajectories, and highlights their distinctive advantages. The objective is to provide an exhaustive overview of the foundational principles of electrochemical sensing systems, analyze the compatibility of hydrogel properties with electrochemical methodologies, and propose potential healthcare applications to further illustrate their applicability. Despite significant advances in the development of hydrogel-based electrochemical biosensors, challenges persist, such as improving material fatigue resistance, interfacial adhesion, and maintaining balanced water content across various environments. Overall, hydrogels have immense potential in flexible biosensors and provide exciting opportunities. However, resolving the current obstacles will necessitate additional research and development efforts., (© 2024 Wiley‐VCH GmbH.)

This Perspective explores the potential of nonpsychoactive cannabinoids (NPCs) such as CBD, CBG, CBC, and CBN in developing innovative biomaterials for biomedical and sports applications. It examines their physicochemical properties, anti-inflammatory, analgesic, and neuroprotective effects, and their integration into various biomaterials such as hydrogels, sponges, films, and scaffolds. It also discusses the current challenges in standardizing formulations, understanding long-term effects, and understanding their intrinsical regulatory landscapes. Further, it discusses the promising applications of NPC-loaded materials in bone regeneration, wound management, and drug delivery systems, emphasizing their improved biocompatibility, mechanical properties, and therapeutic efficacy demonstrated in vitro and in vivo . The review also addresses innovative approaches to enhance NPC delivery including the use of computational tools and explores their potential in both biomedical and sports science contexts. By providing a comprehensive overview of the current state of research, this review aims to outline future directions, emphasizing the potential of NPCs in biomaterial science and regenerative medicine.

A major challenge in tissue engineering scaffolds is controlling scaffold degradation rates during healing while maintaining mechanical properties to support tissue formation. Hydrogels are three-dimensional matrices that are widely applied as tissue scaffolds based on their unique properties that can mimic the extracellular matrix. In this study, we develop a hybrid natural/synthetic hydrogel platform to tune the properties for tissue engineering scaffold applications. We modified chitosan and poly(vinyl alcohol) (PVA) with photo-cross-linkable methacrylate functional groups and then synthesized a library of chitosan PVA methacrylate hydrogels (ChiPVAMA) with two different photoinitiators, Irgacure 2959 (I2959) and lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP). ChiPVAMA hydrogels showed tunability in degradation rates and mechanical properties based on both the polymer content and photoinitiator type. This tunability could enable their application in a range of tissue scaffold applications. In a 2D scratch wound healing assay, all hydrogel samples induced faster wound closure compared to a gauze clinical wound dressing control. NIH/3T3 cells encapsulated in hydrogels showed a high viability (∼92%) over 14 days, demonstrating the capacity of this system as a supportive cell scaffold. In addition, hydrogels containing a higher chitosan content demonstrated a high antibacterial capacity. Overall, ChiPVAMA hydrogels provide a potential tissue engineering scaffold that is tunable, degradable, and suitable for cell growth.

The Diels-Alder reaction, a classical (4+2) cycloaddition process, holds significant standing within the realms of organic synthesis and polymer chemistry, frequently employed in areas such as pharmaceutical production and material science. Recently, hydrogels constructed via Diels-Alder reactions have garnered considerable attention from researchers. This review aims to summarize the advancements in utilizing the Diels-Alder reaction for hydrogel synthesis, exploring its impact on structural design, functionalization, and application domains. Initially, the fundamental principles of the Diels-Alder reaction are introduced alongside an examination of its benefits and characteristics in hydrogel fabrication. Subsequently, applications of Diels-Alder-generated hydrogels in biomedicine, smart responsive materials, drug delivery systems, among other fields, are comprehensively reviewed. Challenges and limitations encountered during hydrogel synthesis using this reaction are also discussed. Finally, prospective research directions and future prospects of Diels-Alder reactions in hydrogel synthesis are contemplated., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Due to the easy preparation, high stability and environmental friendliness, nanozymes are frequently used as promising substitutes to natural enzymes. However, the efficacy of nanozymes in biomedicine aspects is often hampered by their potential biotoxicity and limited bioavailability, which prompted structure adaption or carrier design to maximize nanozymes performance. Despite considerable efforts on carriers to deliver nanozymes efficiently, the systematic studies on enzyme-like activities of nanozymes related to platforms of nanozyme@carrier are sparse. Here, five types of hydrogel carriers composed by sodium alginate (SA), chitosan, gelatin, gelatin methacryloyl (GelMA), and polyacrylamide (PAM) were formed by distinct mode of polymerization to optimize the suitable carrier for peroxidase (POD)-mimic nanozyme consisted of hemin and bovine serum albumin (BSA). Among these proposed carriers, SA hydrogel emerged as the most effective carrier due to its compatible crosslinking mechanism and desirable stability for nanozyme functioning. By incorporating the POD-mimic nanozyme into the SA hydrogel, the catalytic performance of the nanozyme was effectively preserved, leading to improved antibacterial effects and superior sensing ability towards the colorimetric measurement of H 2 O 2 . Based on the rationalization of hydrogel carriers, the proposed study not only helped to understand the structure-function relationship between nanozyme and carriers, but provided an integrated nanoplatform of POD-mimic nanozyme with environmental disinfection as well as biomedical 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.)

Human induced pluripotent stem cell (iPSC)-derived alveolar organoids have emerged as a system to model the alveolar epithelium in homeostasis and disease. However, alveolar organoids are typically grown in Matrigel, a mouse sarcoma-derived basement membrane matrix that offers poor control over matrix properties, prompting the development of synthetic hydrogels as a Matrigel alternative. Here, we develop a two-step culture method that involves pre-aggregation of organoids in hydrogel-based microwells followed by embedding in a synthetic hydrogel that supports alveolar organoid growth, while also offering considerable control over organoid and hydrogel properties. We find that the aggregated organoids secrete their own nascent extracellular matrix (ECM) both in the microwells and upon embedding in synthetic hydrogels, which supports their growth. Thus, the synthetic hydrogels described here allow us to de-couple exogenous and nascent ECM to interrogate the role of ECM in organoid formation., Competing Interests: Declaration of interests D.N.K. holds intellectual property relating to alveolar organoids. J.R.S. and T.F. hold intellectual property related to lung organoid technologies., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Micro- and nanorobots excel in navigating the intricate and often inaccessible areas of the human body, offering immense potential for applications such as disease diagnosis, precision drug delivery, detoxification, and minimally invasive surgery. Despite their promise, practical deployment faces hurdles, including achieving stable propulsion in complex in vivo biological environments, real-time imaging and localization through deep tissue, and precise remote control for targeted therapy and ensuring high therapeutic efficacy. To overcome these obstacles, we introduce a hydrogel-based, imaging-guided, bioresorbable acoustic microrobot (BAM) designed to navigate the human body with high stability. Constructed using two-photon polymerization, a BAM comprises magnetic nanoparticles and therapeutic agents integrated into its hydrogel matrix for precision control and drug delivery. The microrobot features an optimized surface chemistry with a hydrophobic inner layer to substantially enhance microbubble retention in biofluids with multiday functionality and a hydrophilic outer layer to minimize aggregation and promote timely degradation. The dual-opening bubble-trapping cavity design enables a BAM to maintain consistent and efficient acoustic propulsion across a range of biological fluids. Under focused ultrasound stimulation, the entrapped microbubbles oscillate and enhance the contrast for real-time ultrasound imaging, facilitating precise tracking and control of BAM movement through wireless magnetic navigation. Moreover, the hydrolysis-driven biodegradability of BAMs ensures its safe dissolution after treatment, posing no risk of long-term residual harm. Thorough in vitro and in vivo experimental evidence demonstrates the promising capabilities of BAMs in biomedical applications. This approach shows promise for advancing minimally invasive medical interventions and targeted therapeutic delivery.

Mechanically robust and electrically conductive hydrogels hold significant promise for flexible device applications. However, conventional fabrication methods such as casting or injection molding meet challenges in delivering hydrogel objects with complex geometric structures and multicustomized functionalities. Herein, a 3D printable hydrogel with excellent mechanical properties and electrical conductivity is implemented via a facile one-step preparation strategy. With vat polymerization 3D printing technology, the hydrogel can be solidified based on a hybrid double-network mechanism involving in situ chemical and physical dual cross-linking. The hydrogel consists of two chemical networks including covalently cross-linked poly(acrylamide- co -acrylic acid) and chitosan, and zirconium ions are induced to form physically cross-linked metal-coordination bonds across both chemical networks. The 3D-printed hydrogel exhibits multiple excellent functionalities including enhanced mechanical properties (680% stretchability, 15.1 MJ/m 3 toughness, and 7.30 MPa tensile strength), rapid printing speed (0.7-3 s/100 μm), high transparency (91%), favorable ionic conductivity (0.75 S/m), large strain gauge factor (≥7), and fast solvent transfer induced phase separation (in ∼3 s), which enable the development of high-performance flexible wearable sensors, shape memory actuators, and soft pneumatic robotics. The 3D printable multifunctional hydrogel provides a novel path for customizing next-generation intelligent soft devices.

The use of synthetic hydrogels in wastewater treatment represents a promising and scalable approach to achieving clean water. By modulation of their chemical structure, hydrogels can effectively remove a wide range of toxic compounds, including emerging organic pollutants and heavy metals. For the latter, recovery is essential for both environmental protection and metal recycling. The increasing demand for gold, a nonrenewable metal widely used in many technologies, calls for methods for its selective recovery from complex metal cation solutions. This study explores easy-to-make poly(acrylamide- co -acrylic acid) hydrogels as adsorbents for gold recovery from industrial wastewater containing other precious metals. Such material can reduce gold cations into elemental nanoparticles and microparticles in acid environments at room temperature. This process offers a potential route for metal recovery that is not based on weak interaction or complex formation. Batch tests demonstrate a good adsorption capacity (up to 124 mg/g) and efficient separation from other precious metal ions (Ru, Ir, Pd, Pt, and Rh) in a solution that closely mimics realistic industrial waste conditions. These hydrogels would enable gold recovery also from other complex metal solutions, including those derived from the dissolution of electronic wastes.

Polymeric hydrogels, characterized by their highly hydrophilic three-dimensional network structures, boast exceptional physical and chemical properties alongside high biocompatibility and biodegradability. These attributes make them indispensable in various biomedical applications such as drug delivery, tissue engineering, wound dressings and sensor technologies. With the integration of artificial intelligence (AI), hydrogels are undergoing significant transformations in design, leveraging human-machine interaction, machine learning, neural networks, and 3D/4D printing technology. This article provides a concise yet comprehensive overview of polysaccharide-based hydrogels, exploring their intrinsic properties, functionalities, preparation techniques, and classifications, alongside their progress in biomedical research. Special emphasis is placed on AI-enhanced hydrogels, underscoring their transformative potential in redefining hydrogel performance and functionality. By integrating AI technologies, these intelligent hydrogels open unprecedented opportunities in precision medicine, adaptive biomaterials, and smart healthcare systems, highlighting promising directions for future research., 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.)

Aqueous zinc batteries (AZBs) hold great potential for green grid-scale energy storage due to their affordability, resource abundance, safety, and environmental friendliness. However, their practical deployment is hindered by challenges related to the electrode, electrolyte, and interface. Functional hydrogels offer a promising solution to address such challenges owing to their broad electrochemical window, tunable structures, and pressure-responsive mechanical properties. In this review, the key properties that functional hydrogels must possess for advancing AZBs, including mechanical strength, ionic conductivity, swelling behavior, and degradability, from a perspective of the full life cycle of hydrogels in AZBs are summarized. Current modification strategies aimed at enhancing these properties and improving AZB performance are also explored. The challenges and design considerations for integrating functional hydrogels with electrodes and interface are discussed. In the end, the limitations and future directions for hydrogels to bridge the gap between academia and industries for the successful deployment of AZBs are discussed., (© 2024 Wiley‐VCH GmbH.)

Supramolecular hydrogels assembled from amino acids, particularly offer promising prospects as biomimetic three-dimensional extracellular matrices. Phenylalanine, an aromatic amino acid, can self-assemble via hydrophobic interactions, notably through 𝜋 - 𝜋 stacking between phenyl rings. Although the self-assembly processes have been studied, the gelation mechanism of phenylalanine as an individual amino acid has received limited attention in the literature. This study focuses on investigating the gelation behavior of phenylalanine. Fluorescence spectroscopy, along with UV- Visible spectroscopy, and Fourier-transform infrared spectroscopy, were employed to elucidate the molecular interactions and the self-assembly process responsible for hydrogel formation. By leveraging fluorescence spectroscopy, this study aims to elucidate the mechanisms underlying the hydrogelation process. The fluorescence properties of the synthesized hydrogels are extensively examined, providing insights into their structural organization and stability, In this study, we employed a simple heating-cooling method for preparing phenylalanine hydrogel resulting in the formation of opaque hydrogels. Spectral analyses revealed the molecular interactions and structural organization, highlighting the relationship between concentration, opacity, and gel properties. Through this study, we investigated the gelation mechanism of a simple molecule using fluorescence spectroscopy, which provides a foundation for exploring the use of the same in other hydrogel-forming systems., Competing Interests: Declarations. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Macrophages are rapidly activated and polarized toward the M1 phenotype after spinal cord injury (SCI), and inhibiting M1-like macrophages has emerged as a promising SCI treatment approach. Metalloregulatory proteins, which sense specific metal ions with high affinity and specificity, play a critical role in immune regulation. Here, we screened various bioactive metal ions associated with metalloregulatory proteins and discovered that Zn 2+ and Mn 2+ effectively suppressed M1 polarization. Based on these findings, mildly alkaline ZnMn-based layered double hydroxides (ZnMn-LDHs) self-assembled from Zn 2+ coordinated with Mn 2+ were developed to inhibit M1-like macrophages. ZnMn-LDHs effectively neutralized the acidic environment and promoted the expression of metalloregulatory proteins, including metallothionein (MT), superoxide dismutase 1 (SOD1), and superoxide dismutase 2 (SOD2), thereby eliciting robust M1-like macrophage inhibition. More importantly, nerve growth factor (NGF) released by macrophages following the regulation by ZnMn-LDHs promoted the elongation and spreading of Schwann cells. By integrating ZnMn-LDHs with silk fibroin (SF), ZnMn@SF injectable hydrogels were constructed for SCI repair. An in vivo animal model further revealed the excellent anti-inflammatory effects of the ZnMn@SF hydrogels in treating SCI, which promoted functional recovery. Our findings underscore the importance of metalloregulatory proteins regulated by metal ions in inhibiting M1-like macrophages, providing a promising therapeutic strategy for SCI treatment.

In the field of tissue engineering, determining the mechanical properties of hydrogels is a key prerequisite to develop biomaterials mimicking the properties of the extracellular matrix. In mechanobiology, understanding the relationships between the mechanical properties and physiological state of cells is also essential. Time-dependent mechanical characterization of these soft materials is commonly achieved by atomic force microscopy (AFM) experiments in liquid environment. However, the determination of an appropriate model to correctly interpret the experimental data is often missing, making it difficult to extract quantitative mechanical properties. Here, force relaxation and force-distance curves were combined to elucidate the origin of dissipative processes involved in hydrogels and cells, before applying the relevant poroelastic or viscoelastic theory to model the curves. By using spherical AFM tips, analytical equations were developed to transform these curves into mechanical parameters by describing the relationships between the exerted force and the elastic, poroelastic or viscoelastic responses of semi-infinite and finite-thickness materials. Poroelastic behavior was evidenced for a thermoresponsive hydrogel and a set of poroelastic parameters was extracted from the force relaxation curves. In contrast, cells exhibited viscoelastic properties characterized by a single power-law relaxation over three-decade time scales. In addition, compressive modulus and fluidity exponent of cells were obtained by fitting force relaxation curves and approach-retraction force-distance curves. This combined theoretical and experimental framework opens a rigorous way toward quantitative mechanical properties of soft materials by (1) systematically determining the origin of their relaxation mechanisms, (2) defining the theoretical models to correctly interpret the experimental data, (3) using analytically solved equations to extract the mechanical parameters., 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 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background and Aims: An effective surgical adhesive must possess strength, biodegradability, flexibility, non-toxicity, and the ability to accommodate to tissue movement. However, existing adhesives in the market lack some of these crucial properties. Both synthetic cyanoacrylate and natural fibrin glue have been explored for sutureless oral surgery, but they come with specific limitations. This perspective review aims to explore the novel potential of hydrogels as bioadhesives for wound closure in the oral cavity., Methods: This review thoroughly examines the properties, applications, and limitations of hydrogels as bioadhesive materials for wound closure within the human body., Results: We first provide a comprehensive description of materials used for sutureless oral surgery. Next, drawing on our expertise in the field of oral surgery, we propose novel potential applications for hydrogels in oral wound closure. We showed that Hydrogels represent promising bioadhesives in medical field and are undergoing continuous enhancement to expand their applications in wound closure., Conclusion: Although hydrogels have been utilized in various dental conditions, their potential for closing wounds in the oral cavity remains unexplored., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Health Science Reports published by Wiley Periodicals LLC.)

Peptide building blocks have been recently proposed for the fabrication of supramolecular nanostructures able to encapsulate and in vivo deliver drugs of a different nature. The primary sequence design is essential for nanostructure property modulation, directing and affecting affinity for specific drugs. For instance, the presence of positively charged residues of lysine (K) or arginine (R) could allow improving electrostatic interactions and, in turn, the encapsulation of negatively charged active pharmaceutical ingredients, including nucleic acids. In this context, here, we describe the formulation and the multiscale structural characterization of hybrid cationic peptide containing hydrogels (HGs). In these matrices, the well-known low-molecular-weight hydrogelator, Fmoc-diphenylalanine (Fmoc-FF, Fmoc = fluorenyl methoxycarbonyl), was mixed with a library of cationic amphiphilic peptides (CAPs) differing for their alkyl chain (from C8 to C18) in a 1/1 mol/mol ratio. The structural characterization highlighted that in mixed HGs, the aggregation is guided by Fmoc-FF, whereas the cationic peptides are only partially immobilized into the hydrogelated matrix. Moreover, morphology, stiffness, topography, and toxicity are significantly affected by the length of the alkyl chain. The capability of the hydrogels to encapsulate negative drugs was evaluated using the 5-carboxyfluorescein (5-FAM) dye as a model.

Organic conducting polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has garnered enormous attention in organic electronics due to its low-cost solution processability, highly tunable conductivity, superior mechanical flexibility, and good biocompatibility together with excellent atmospheric stability. Nevertheless, limited electrical properties and unfavorable water instability of pristine PEDOT:PSS film impede its further implementation in a broad spectrum of practical applications. In this work, the successful tailoring of the intrinsic electrostatic interaction within PEDOT:PSS and consequent optimized electrical properties are enabled by a simple yet effective ionic salt post-treatment strategy. The choice of zinc di[bis(trifluoromethylsulfonyl)imide] (Zn(TFSI) 2 ) not only endows the post-treated PEDOT:PSS film with high electrical properties but also other compelling characteristics, including superior water stability, excellent mechanical flexibility, and fast humidity responsiveness. Multidimensional characterizations are conducted to gain in-depth insights into the mechanisms underlying such improved performance, ranging from intermolecular interactions, polymer conformations, and doping levels to microstructural characteristics. Benefiting from these versatile properties, the as-prepared freestanding Zn(TFSI) 2 -post-treated PEDOT:PSS films can serve as promising candidates for high-performance polymeric materials integrated into multifunctional flexible electronics, including thermoelectric power generators, conductive hydrogels, and humidity-responsive actuators. This study demonstrates a facile methodology for the exploration of multifunctional conducting polymers, whose implications can extend across a wide range of next-generation wearable devices, bioelectronics, and soft robotics.

Hydrogels have become common in wound treatment because they form very stable and biocompatible environments that promote healing. However, due to the highly porous hydrogel structure, any therapeutic added to these gels tends to diffuse quickly and impact delivery to the target site. Aptamers are short, single-stranded DNA or RNA sequences that bind specifically to a target, so aptamers that bind to hydrogels could serve as tags for therapeutics to prevent rapid diffusion and allow for extended delivery. An in vitro selection approach was developed to identify DNA aptamers for alginate hydrogels. Two DNA aptamers were shown to bind hydrogels ranging from 0.5 to 2% alginate and could be either encapsulated during gelation or introduced to preformed gels. Both aptamers also showed specificity for binding to alginate compared to agarose. To demonstrate the functional aspect of the aptamers as tethers for other biomolecules, both aptamers were conjugated to BSA. Aptamer-conjugated BSA was retained longer in the hydrogel during week-long diffusion studies both when encapsulated or introduced to preformed gels, which adds flexibility to how these aptamers can be deployed in a clinical setting.

Investigation of brain neural circuits is essential for deciphering the diagnostics and therapeutics of neurodegenerative diseases. The main concerns with traditional rigid metal electrodes include intrinsic mechanical mismatch between sensing electrodes and tissues, unavoidable foreign body responses, and inadequate spatiotemporal resolution, resulting in a deficiency of sensing performance. All-hydrogel neural electrodes with multi-electrode arrays (MEAs) suggest a viable way to modulate the trade-off between tissue-mechanical compliance and excellent spatiotemporal recording capacity, but still face the issues of insufficient conductivity and unstable interlayer bonding. Herein, we constructed a four-layer all-hydrogel neural electrode, by sandwiching a conductive hydrogel layer within two encapsulation hydrogel layers, with a shielding hydrogel layer located on top. We introduce a dual-strategy treatment to induce controllable phase separation in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hydrogel, which achieved ultra-high conductivity (up to 4176 S cm -1 ) comparable to that of metals and precise spatial resolution (∼15 μm) suitable for single neuron recording. In addition, the utilization of polyphenol chemistry mediated adaptive adhesion endowed this neural electrode with flexible and stable interlayer bonding among conductive-encapsulation-shielding layers and the tissue-electrode interface. Consequently, the all-hydrogel neural electrode exhibited a tenfold higher signal-to-noise ratio than a commercial silver electrode, realized the recording of weak neural activity signals within single and multiple neurons in epileptic rats, and applied man-made stimulation to the cerebral cortex of rats during seizures. This work provides a useful tool to understand the development, function and treatment of neurodegenerative diseases.

This study introduces a green method for preparing self-assembly hydrogels via polyelectrolyte complex (PEC) coacervation using chitosan, sulphated polysaccharides (chondroitin sulphate or fucoidan), and hydrolyzed collagen, followed by treatments, such as centrifugation, nanocellulose incorporation, algal fucoidan substitution, freezing-thawing, saline solution addition, and dialysis. Chitosan alters the non-gelling characteristics of chondroitin sulphate, fucoidan, and hydrolyzed collagen, initiating quick gelling. This study compared the effects of biopolymer concentrations, pHs, and treatments on hydrogel properties. Hydrogels fabricated using sulphated polysaccharides from different sources demonstrated distinct properties. Nanocellulose incorporation significantly modified the hydrogel performance, with hydrogel containing 4 % nanocellulose showing the lowest E-factor (~1 kg waste/kg product), the highest swelling capacity (up to 766 %), robust rheological strength (storage modulus >20 kPa), interconnected fibrous, highly porous structures, and outstanding thermal stabilities (no significant degradation below 200 °C). The hydrogels also exhibited self-healing and injectable potentials. Centrifugation further improved solid-like behaviours through compacting structures and enhancing interactions. Biopolymer concentrations and pHs had minimal impacts on hydrogel properties. The tailored properties resulting from the biopolymer components and treatments indicated the potential for customizing biomaterial functionality for biomedical applications. The eco-friendly synthesis of PEC hydrogels from marine by-products leverages underutilized renewable resources, contributing to a sustainable bioeconomy., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Azadeh Kermanshahi-pour reports financial support was provided by Mitacs Canada. Jianan Lin reports financial support was provided by Nova Scotia Graduate Scholarship. If there are other authors, they 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. Published by Elsevier B.V.)

Full bio-degradation of super absorbent hydrogels (SAHs), which possess excellent water uptake capacity, is still challenging. Based on Flory theory, this paper first analyzes that the high swelling property and gel strength of SHAs are attributed to the length of effective chain of crosslinker. Firstly, a series of hyperbranched crosslinker (HBC) with different molecular weights were designed and synthesized by anionic polymerization and sodium lignosulfonate (SL), which owns a hydrophilic network and remarkable biodegradation properties, was selected as a monomer. Compared with the shorter chain formaldehyde-urea crosslinker (SL-FU), the swelling performance of the gel is improved by about 22 % when long chain polyethylene glycol is used as crosslinker (SL-PEGDA400). Furthermore, SL crosslinked with HBC (PSLH) showed the highest water absorption properties of 664.3 g/g in deionized water and 69.8 g/g in normal saline water when the adding amount of HBE was 11.25 % (ratio to mass of SL, Mn = 5600 g/mol), which is about 16 times and 14 times higher than that of SL-Fu and SL-PEGDA400, respectively. The rate of natural degradation was over 96 %, which was buried in the soil for 270 days. In addition, PSLH as a substitute for petroleum-based products was applied in diapers, showing high adaptability, which indicated promising applicability for producing commercial hygiene productions., 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. Published by Elsevier B.V.)

Hydrogels have been identified as a promising material platform for solar-driven interfacial evaporation. However, designing durable hydrogel solar evaporators that can combine effective photothermal conversion, superior water transport, salt resistance, and robust mechanical properties to ensure stable and efficient evaporation remains a significant challenge. Herein, a robust and antifouling hydrogel-based solar evaporator composed of poly(vinyl alcohol), sodium alginate, and MXene is successfully constructed through directional freeze-casting and salting-out processes. The directional freeze-casting aids in forming vertically aligned, well-interconnected channels within the hydrogel that facilitate rapid upward water transfer and effective salt ion discharging, while the optimized salting-out process promotes the cross-linking of polymer chains, creating a sponge-like porous structure that enhances key mechanical properties such as high elasticity and exceptional flexibility. The developed hydrogel evaporator achieves an impressive evaporation rate of 2.53 kg m -2 h -1 with an energy efficiency of 93%, as well as excellent salt resistance and long-term evaporation stability even when desalinating high-concentration brines. These exceptional characteristics make this composite hydrogel evaporator highly suitable for practical applications in seawater desalination and wastewater purification.

Glioblastoma multiforme (GBM), a common malignant neurological tumor, has boundaries indistinguishable from those of normal tissue, making complete surgical removal ineffective. The blood-brain barrier (BBB) further impedes the efficacy of radiotherapy and chemotherapy, leading to suboptimal treatment outcomes and a heightened probability of recurrence. Hydrogels offer multiple advantages for GBM diagnosis and treatment, including overcoming the BBB for improved drug delivery, controlled drug release for long-term efficacy, and enhanced relaxation properties of magnetic resonance imaging (MRI) contrast agents. Hydrogels, with their excellent biocompatibility and customizability, can mimic the in vivo microenvironment, support tumor cell culture, enable drug screening, and facilitate the study of tumor invasion and metastasis. This paper reviews the classification of hydrogels and recent research for the diagnosis and treatment of GBM, including their applications as cell culture platforms and drugs including imaging contrast agents carriers. The mechanisms of drug release from hydrogels and methods to monitor the activity of hydrogel-loaded drugs are also discussed. This review is intended to facilitate a more comprehensive understanding of the current state of GBM research. It offers insights into the design of integrated hydrogel-based GBM diagnosis and treatment with the objective of achieving the desired therapeutic effect and improving the prognosis of GBM.

Background: Moldable hydrogel-based techniques loaded with osteoinductive agents such as metformin have become a promising field for reconstructing critical-sized bone defects, particularly in those with irregular shapes. Here, we used metformin incorporated in an alginate/hydroxyapatite hydrogel to accelerate the repair of the rabbit critical-sized mandibular defect., Methods: Cytotoxicity and osteoinduction of the metformin-loaded alginate/hydroxyapatite hydrogel were evaluated by culturing the osteosarcoma cell line (MG63). Moreover, in vivo bone formation was assessed in a rabbit bone defect model using computed tomography and histomorphometric analysis to compare the effects of alginate/hydroxyapatite hydrogel with or without metformin., Results: The data showed that the scaffolds were not cytotoxic and enhanced osteogenic characteristics of the cells, as manifested by augmented alkaline phosphatase activity and calcium deposition . In vivo studies indicated that all the treated groups exhibited more osteogenesis with a significant increase in bone-specific cell population and less residual scaffold remnant at the defect sites compared with the control group, which was significantly prominent in the group treated with alginate/hydroxyapatite/metformin. Moreover, computed tomography scan analysis also confirmed better bone filling in all the treated groups, especially in the defects treated with alginate/hydroxyapatite/metformin hydrogel., Conclusions: Both In vitro and in vivo experiments revealed that locally loaded metformin with the easy size- and shape-adapted alginate/hydroxyapatite hydrogel has proper biocompatibility and osteogenesis properties. Moreover, our study highlighted the synergistic effect of metformin and hydroxyapatite on osteogenesis., Competing Interests: Conflict of interestThe authors have no conflict of interest to disclose., (© The Association of Oral and Maxillofacial Surgeons of India 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Blood glucose fluctuation leads to poor bone defect repair in patients with type 2 diabetes (T2DM). Strategies to safely and efficiently improve the bone regeneration disorder caused by blood glucose fluctuation are still a challenge. Neutral sphingophospholipase 2 (Smpd3) is downregulated in jawbone-derived bone marrow mesenchymal stem cells (BMSCs) from T2DM patients. Here, we investigated the effect of Smpd3 on the osteogenic differentiation of BMSCs and utilized exosomes from stem cells overexpressing Smpd3 as the main treatment based on the glucose responsiveness of phenylboronic acid-based polyvinyl alcohol crosslinkers and the protease degradability of gelatin nanoparticles. The combined loading of Smpd3-overexpressing stem cell-derived exosomes (Exos-Smpd3) and nanosilver ions (Ns) to construct a hydrogel delivery system (Exos-Smpd3@Ns) promoted osteogenesis and differentiation of BMSCs in a glucose-fluctuating environment, ectopic osteogenesis of BMSCs in a glucose-fluctuating environment and jawbone regeneration of diabetic dogs in vitro. Mechanistically, Smpd3 promoted the osteogenesis and differentiation of jawbone-derived BMSCs by activating autophagy in the jawbone and inhibiting macrophage polarization and oxidative stress caused by blood glucose fluctuations. These results reveal the role and mechanism of Smpd3 and the Smpd3 overexpression exosome delivery system in promoting BMSC function and bone regeneration under blood glucose fluctuations, providing a theoretical basis and candidate methods for the treatment of bone defects in T2DM patients., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Astaxanthin is a red-orange keto-carotenoid exhibiting antioxidant activity. AST is mainly used in the cosmetic, food, and healthcare industries. Nevertheless, because of its anti-inflammatory effects and immune modulation activity, AST use in pharmacology has been proposed as an alternative for treating neurodegenerative disorders, inflammatory bowel disease, arthritis, atherosclerosis, or diabetic foot ulcers, among others. However, before an AST clinical implementation, it is still necessary to solve challenges related to the use of AST, such as lack of solubility, poor bioavailability, and sensitivity to light, oxygen, and temperature. For that reason, the development of several biomaterials to encapsulate, protect, and dosage AST has been proposed in recent years. This review discusses the use of liposomes, hydrogels, and polymer micro and nanoparticles as vehicles for AST release based on available literature. Additionally, an analysis of released, encapsulated, and effective AST doses is presented, as well as the regulatory landscape of different delivery systems to reveal details of AST delivery, which should inform future strategies for implementing AST in the clinic., 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 The Authors. Published by Elsevier B.V. All rights reserved.)

This manuscript reports on the effect of different bile salts concentration on the gastrointestinal digestion of casein and casein-agar hybrid systems and evaluates the effect on the nanostructural assembly of the digestion products through the application of advanced small angle X-ray scattering analysis (SAXS). The results showed that bile salts promote the hydrolysis of micellar casein upon in vitro gastrointestinal digestions. It is noteworthy that in the presence of agar, bile salts interact with the polysaccharide, leading to a reduction in their proteolytic activity. While structured agar-casein hydrogels were shown to be able to limit the proteolysis during the gastric phase, increasing concentrations of bile salts promoted the diffusion of casein from the gel network during the intestinal phase, hence leading to higher degree of hydrolysis. The released digestion products were seen to interact with bile salts, forming ordered lamellar/micellar nanostructures. In particular, the presence of solubilized agar in the digesta was seen to promote the formation of these nanostructures. These nanostructures were formed at 10 mM bile salts for the hydrogels, and across all concentrations for agar-casein blends. Thus, this work demonstrates the great relevance of bile salts in the nanostructural assembly of protein digestion products, which is expected to have a great relevance in bioavailability and metabolic responses induced by protein-rich foods., 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 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Oral wounds caused by injuries, surgeries, diseases, and chemical irritations bring pain to the patient and increase the risk of infection. Effective wound protection and repair are crucial for improving patients' quality of life and maintaining oral health. Wound dressings provide ideal healing conditions by isolating the wound from the oral environment. However, in the highly moist, microbiologically rich environment of the oral cavity, maintaining the stability of wound dressings remains a considerable challenge. Hydrogels show promising prospects for oral applications and are gradually becoming a research hotspot for addressing the challenges of oral wound protection and repair due to their excellent biocompatibility and versatile performance. In this paper, the current design strategies of hydrogel wound dressings that overcome the unique oral environment, achieve sustained adhesion and fulfill their functions are reviewed to provide new insights for the design of ideal oral wound barrier materials.

Polysaccharides such as sodium alginate, pectin and gellan gum are widely used biomaterials, for their ability to easily form hydrogels in the presence of divalent metal ions, such as calcium - a process often cited as a mild crosslinking mechanism. However, when using these materials as substrates for tissue engineering, there is a lack of extensive studies that investigate the impact of elevated calcium concentrations on cell health and behaviour. In this study, we performed an in-depth exploration to understand the potential effects of raising extracellular CaCl 2 on cell viability, proliferation, morphology and migration. We used an established glioblastoma (GBM) cell line (U251), human dermal fibroblasts (HDF), and murine osteoblasts (MC3T3) to assess the consequences of using CaCl 2 in tissue engineered models to help reevaluate biomaterial suitability and enhance standardisation practices in the field of tissue engineering. Our findings revealed that the addition of CaCl 2 induced notable morphological changes in GBM cells when cultured in 3D hydrogels with excess CaCl 2 added, leading to a transition from mesenchymal to amoeboid phenotypes, even at a concentration as low as 8 mM. Furthermore, cell viability was reduced in a concentration-dependent manner across all cell types, and migration was also affected. Despite the widespread use of high CaCl 2 concentrations to facilitate scaffold gelation, our research unveils that there can be significant risks to cell viability, proliferation, morphology, and migration when such practices are not preceded by cell line-specific experimentation and thorough standardization procedures. This highlights the importance of careful consideration and optimisation of CaCl 2 concentration when used as a crosslinking agent for hydrogels intended for use in tissue engineering applications that demand accurate recapitulation of cellular responses and physiological conditions., 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 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In recent decades, significant advancements have been made in wound healing treatments, mainly due to the development of biopolymer-based hydrogels. These injectable self-healing hydrogels have attracted considerable interest because of their unique attributes, including reversible chemistry, injectability, and printability. Unlike traditional hydrogels, injectable polysaccharide-based self-healing hydrogels offer numerous benefits. They can be tailored to fit individual patients, significantly advancing personalized medicine. Upon injection, these hydrogels transform in situ into a substance that effectively covers the entire lesion in all three dimensions, reaching irregular and deep lesions. Injectable self-healing hydrogels also play a pivotal role in promoting tissue regeneration. Their diffusive and viscoelastic properties allow for the controlled delivery of cells or therapeutics in a spatiotemporal manner, provide mechanical support, and facilitate the local recruitment and modulation of host cells. Consequently, these hydrogels have revolutionized innovative approaches to tissue regeneration and are ideally suited for managing chronic wounds. This review paper presents a comprehensive classification of injectable self-healing hydrogels commonly used in chronic wound repair and provides a detailed analysis of the various applications of injectable self-healing hydrogels in treating chronic wounds, thereby illuminating this rapidly evolving field., 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.)

Hydrogels composed of polysaccharides and silver nanoparticles (AgNPs) are widely recognized for their applications in wound dressings, particularly for healing wounds prone to infection. Traditional methods for preparing AgNPs immersed hydrogels are often complex, costly, and may lead to sustained cytotoxicity. To address these challenges, we developed a biocompatible, one-step green reduction strategy to generate AgNPs within hydrogels using a triple-helix β-glucan (PCPA) derived from Poria cocos, a renowned Chinese traditional herb. PCPA serves as a reducing agent, converting silver ions into AgNPs while its triple-helix conformation prevents AgNPs aggregation. The resulting hydrogel (PAg-G) is injectable and contains uniformly distributed AgNPs. PAg-G exhibits broad-spectrum antimicrobial activity and enhanced bioactivity. The in vivo study on S.aureus-infected SD rats demonstrated that PAg-G can accelerate wound healing within 12 days by down-regulating inflammatory factors such as IL-6 and TNF-α, and up-regulating VEGF and CD31 expression, promoting neovascularization in wound tissues. This innovative one-step construction of AgNPs immersed hydrogels offers a promising approach for the development of antimicrobial hydrogels, especially for treating bacterial-infected wounds., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest to the manuscript titled “One-step Construction of Silver Nanoparticles Immersed Hydrogels by Triple-helix β-glucans and the Application in Infectious Wound Healing” submitted to International Journal of Biological Macromolecules., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This research focuses on the modification of pectin through an amination reaction, followed by the development of a novel iminodiacetic acid-functionalized pectin/montmorillonite hydrogel nanocomposite (IMAP/MMT) using gamma radiation. This composite was investigated as an adsorbent for 4-nitrophenol removal from aqueous solutions. Central composite design was utilized for numerical optimization, identifying the maximum adsorption capacity under optimal conditions [0.8 g/L; 52 min;4 pH, 73 mg/L). A decrease in Q m (330.19 to 273.96 mg/g) with increasing temperature indicated an exothermic adsorption process, supported by the calculated ΔH° value of -28.39 kJ/mol. Analysis of pH, FTIR, and XPS results revealed that the primary mechanisms for 4-nitrophenol uptake include hydrogen bonding, π-π interactions, and n-π interactions. Additionally, the Temkin and D-R isotherms, along with ΔH° values, confirmed the physical nature of the adsorption process, as evidenced by bT (0.70-0.86 kJ/mol) and E (0.74-0.82 kJ/mol) values. The IMAP/MMT composite exhibited superior adsorption selectivity, efficient performance in real water, and good reusability, with a rate of 79.4 % maintained for up to five cycles, highlighting its potential for practical applications as an effective adsorbent. Overall, the findings suggest that IMAP/MMT can serve as an environmentally and economically sustainable material for the removal of 4-nitrophenol from wastewater., 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.)

Oral squamous cell carcinoma (OSCC) often recurs aggressively and metastasizes despite surgery and adjuvant therapy, driven by postoperative residual cancer cells near the primary tumor site. An implantable in situ vaccine hydrogel was designed to target residual OSCC cells post-tumor removal. This hydrogel serves as a reservoir for the sustained localized release of δ-aminolevulinic acid (δ-ALA), enhancing protoporphyrin IX-mediated photodynamic therapy (PDT), and a polydopamine-hyaluronic acid composite for photothermal therapy (PTT). Additionally, immune adjuvants, including anti-CD47 antibodies (aCD47) and CaCO 3 nanoparticles, are directly released into the resected tumor bed. This approach induces apoptosis of residual OSCC cells through sequential near-infrared irradiation, promoting calcium interference therapy (CIT). The hydrogel further stimulates immunogenic cell death (ICD), facilitating the polarization of tumor-associated macrophages from the M2 to the M1 phenotype. This facilitates phagocytosis, dendritic cell activation, robust antigen presentation, and cytotoxic T lymphocyte-mediated cytotoxicity. In murine OSCC models, the in situ vaccine effectively prevents local recurrence, inhibits orthotopic OSCC growth and pulmonary metastases, and provides long-term protective immunity against tumor rechalle nge. These findings support postoperative in situ vaccination with a biocompatible hydrogel implant as a promising strategy to minimize residual tumor burden and reduce recurrence risk after OSCC resection., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

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

Chronic wounds are a critical and costly complication that affects millions of patients each year, especially patients suffering from diabetes, and constitute a serious global healthcare problem that needs immediate attention. In this direction, novel dressings that can integrate appropriate physicochemical and biological features, mechanical durability, and the capacity for therapy are of great clinical importance. For instance, self-healable hydrogels, with antibacterial activity and high tissue adhesion, have attracted increasing attention for wound management applications. Despite their potential, existing self-healable hydrogel networks exhibit limitations in mechanical strength and adhesion, tissue regeneration, antibacterial efficacy, and scalability, indicating a need for further improvement in the field. This review focuses on exactly these recent advances in the field with a special focus on self-healing adhesive hydrogel-based wound dressings as well as their structures, construction strategies, adhesion mechanisms, and emerging usage in the wound healing field. By shedding light on these developments, we aim to contribute to the ongoing pursuit of enhanced solutions for chronic wound care., 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 The Authors. Published by Elsevier B.V. All rights reserved.)

In the current study, four different combinations of hydrogels were synthesized using carboxymethyl tamarind kernel gum (CMTKG), synthetic polymers: polysodiumacrylate (PSA) and polyacrylamide (PAM) and Graphene Oxide (GO) as a filler, and Ciprofloxacin (Cip) as a model drug and then characterized. The swelling behavior of hydrogel reveals the order as Distilled Water (DW) (pH 7) > pH 7.4 > pH 1.2. The gel content (%) of the hydrogels was 79 (D1), 68.7 (D2), 88 (D3), and 76 (D4). Further, studies such as drug loading and drug release were carried out at simulated pH 7.4, pH 5.5, and pH 1.2, which reveals that the maximum drug release (%) was exhibited by D3 (86), followed by D1 (82), D4 (70), and D2 (61) at pH 7.4. The Korsmeyer-Peppa's model suggested the best fit with R 2  = 0.99 for all. Additionally, the antibacterial activity reveals the inhibition zone (mm) for 24 (D1), 16 (D2), 30 (D3), and 19 (D4) hydrogels. The cytotoxicity of hydrogels indicated that the cell survival rate was >68 % in <250 μg/mL concentration for all hydrogels. Hence, incorporating GO can potentially enhance the drug release ability, bactericidal property, and cell survival rate of the hydrogels., 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.)

Dynamic covalent cross-linked (DCC) hydrogels represent a significant advance in biomaterials for regenerative medicine and mechanobiology, offering viscoelasticity, and self-healing properties that more closely mimic in vivo tissue mechanics than traditional, predominantly elastic, covalent hydrogels. However, the effects of varying cross-linker architecture on DCC hydrogel viscoelasticity have not been thoroughly investigated. This study introduces hydrazone-based alginate hydrogels to explore how cross-linker architectures impact stiffness and viscoelasticity. In hydrogels with side-chain cross-linker (SCX), higher cross-linker concentrations enhance stiffness and decelerate stress relaxation, while an off-stoichiometric hydrazine-to-aldehyde ratio reduces stiffness and shortens relaxation time. In hydrogels with telechelic cross-linking, maximal stiffness and relaxation time occurs at intermediate cross-linker mixing ratio for both linear cross-linker (LX) and star cross-linker (SX), with higher cross-linker valency further enhancing these properties. Further, the ranges of stiffness and viscoelasticity accessible with the different cross-linker architectures are found to be distinct, with SCX hydrogels leading to slower stress relaxation relative to the other architectures, and SX hydrogels providing increased stiffness and slower stress relaxation versus LX hydrogels. This research underscores the pivotal role of cross-linker architecture in defining hydrogel stiffness and viscoelasticity, providing insights for designing DCC hydrogels with tailored mechanical properties for specific biomedical applications., (© 2024 Wiley‐VCH GmbH.)

Diabetic wounds, characterized by complex pathogenesis and high infection rates, pose significant challenges in treatment due to prolonged recovery times and high recurrence rates, often leading to severe complications such as amputation and death. Traditional dry dressing treatments fail to address the unique microenvironment of diabetic wounds and tend to cause secondary damage due to frequent replacement. In this study, an electronic-embedding, drug-loading hydrogel bioelectronics is reported for accelerating diabetic wound healing using a combination of programmable pharmaceutical and electrostimulative approaches. Encapsulated in stretchable and biocompatible materials, this device is capable of multiple drug refilling and accelerated drug release modulated by on-board electronics. In vivo experiments on diabetic model rats confirm the device's effectiveness in promoting wound healing. This innovative approach implies the potential for improving diabetic wound management using a combination of physical, material, and pharmaceutical interventions., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Oral ulcers can be addressed using various biomaterials designed to deliver medications or cytokines. Nevertheless, the effectiveness of these substances is frequently limited in many patients due to poor adherence, short retention time in the mouth, and less-than-optimal drug efficacy. In this study, a new hydrogel patch (FSH3) made of a silk fibroin/hyaluronic acid matrix with light-sensitive adhesive qualities infused with ferric iron/shikonin nanoparticles to enhance healing effects is presented. Initially, this hydrogel forms an adhesive barrier over mucosal lesions through a straightforward local injection, solidifying when exposed to UV light. Subsequently, FSH3 demonstrates superior reactive oxygen species elimination and near-infrared photothermal bactericidal activity. These characteristics support bacterial elimination and regulate oxidative levels, promoting a wound's progression from inflammation to tissue regeneration. In a diabetic rat model mimicking oral ulcers, FSH3 significantly speeds up healing by adjusting the inflammatory environment of the injured tissue, maintaining balance in oral microbiota, and promoting faster re-epithelialization. Overall, the light-sensitive FSH3 hydrogel shows potential for rapid wound recovery and may transform therapeutic methods for managing oral ulcers in diabetes., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Solar-powered interfacial water evaporation is a promising technique for alleviating freshwater stress. However, the evaporation performance of solar evaporators is still constrained by low photothermal conversion efficiency and high water evaporation enthalpy. Herein, 0D carbon quantum dots (CQDs) are combined with 2D MXene to serve as a hybrid photothermal material to enhance the light absorption and photothermal conversion ability, meanwhile sodium carboxymethyl cellulose (CMC)/polyacrylamide (PAM) hydrogels are used as a substrate material for water transport to reduce the enthalpy of water evaporation. The synergistic effect in 0D CQDs/2D MXene hybrid photothermal materials accelerate the carrier transfer, inducing efficient localized surface plasmon resonance (LSPR) effect. This results in the enhanced photothermal conversion efficiency. The integrated hydrogel evaporators demonstrate a high evaporation rate (1.93 and 2.86 kg m -2  h -1 under 1 and 2 sunlights, respectively) and low evaporation enthalpy (1485 J g -1 ). In addition, the hydrogel evaporators are applied for photothermal sensing and temperature difference power generation (TEG). The TEG device presents an efficient output power density (230.7 mW m -2 ) under 1 sunlight. This work provides a feasible approach for regulating and controlling the evaporation performances of hydrogel evaporators, and gives a proof-of-concept for the design of multipurpose solar evaporation systems., (© 2024 Wiley‐VCH GmbH.)

Spinal cord injury (SCI) damages the trauma site, leading to progressive and secondary structural defects rostral and caudal to the injury. Interruption of ascending and descending pathways produce motor, sensory, and autonomic impairments, driving the need for effective therapies. In this study, we address lesion site repair and promoting descending projections using a combined biomaterial-neuromodulation strategy in a rat model of cervical contusion SCI. To promote tissue repair, we used Chitosan fragmented physical hydrogel suspension (C fphs ), a biomaterial formulation optimized to mitigate inflammation and support tissue remodeling. To promote descending projections, we targeted the corticospinal motor system with dual motor cortex-trans-spinal direct current neuromodulation to promote spared corticospinal tract (CST) axon sprouting rostral and caudal to SCI. C fphs , injected into the lesion site acutely, was followed by 10 days of daily neuromodulation. Analysis was made at the chronic phase, 8-weeks post-SCI. Compared with SCI only, C fphs alone or in combination with neuromodulation prevented cavity formation, by promoting tissue remodeling at the injury site, abrogated astrogliosis surrounding the newly formed tissue, and enabled limited CST axon growth into the remodeled injury site. C fphs alone significantly reduced CST axon dieback and was accompanied by preserving more CST axon gray matter projections rostral to SCI. C fphs  + neuromodulation produced sprouting rostral and caudal to injury. Our findings show that our novel biomaterial-neuromodulation combinatorial strategy achieves significant injury site tissue remodeling and promoted CST projections rostral and caudal to SCI., Competing Interests: Declaration of competing interest Drs. Fatiha Nothias and Sylvia Soares are co-founders and stock owners of MEDJEDUSE and co-owners of the patent for which MEDJEDUSE owns an exclusive commercial sublicence. They declare no competing financial interests. Ms. Chaimae Ahmanna and Ms. Kadia Kanté were employees of Medjeduse when the work was conducted. The biomaterial being evaluated in this article is provided by MEDJEDUSE., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Repairing infected bone defects is hindered by the presence of stubborn bacterial infections and inadequate osteogenic activity. The incorporation of harmful antibiotics not only fosters the emergence of multidrug-resistant bacteria, but also diminishes the osteogenic properties of scaffold materials. In addition, it is essential to continuously monitor the degradation kinetics of scaffold materials at bone defect sites, yet the majority of bone repair materials lack imaging capability. To address these issues, this study reports for the first time the development of a single nanomaterial with triple functionality: efficient sonodynamic antibacterial activity, accelerated bone defect repair capability, and NIR imaging ability for visualized therapy of infected bone defects. Through rationally regulating the surface functional groups, the obtained multifunctional NIR carbon dots (NIR-CD) exhibit p-n junction-enhanced sonodynamic activity, narrow bandgap-facilitated NIR imaging capability, and negative charge-augmented osteogenic activity. The validation of NIR-CDs antibacterial and osteogenic activities in vivo is conducted by constructing 3D injectable hydrogels encapsulated by NIR-CDs (NIR-CD/GelMA). The implantation of multifunctional NIR-CD/GelMA hydrogel scaffolds in a model of MRSA-infected craniotomy defects results in almost complete restoration of the infected bone defects after 60 days. These findings will provide traceable, renewable, repairable and antibacterial candidate biomaterials for bone tissue engineering., (© 2024 Wiley‐VCH GmbH.)

Regeneration of orofacial tissues is hampered by the lack of adequate vascular supply. Implantation of in vitro engineered, prevascularized constructs has emerged as a strategy to allow the rapid vascularization of the entire graft. Given the angiogenic properties of dental pulp stem cells, we hereby established a preclinical model of prevascularized constructs loaded with stem cells from human exfoliating deciduous teeth (SHED) in a 3-dimensional-printed material and provided a functional analysis of their in vivo angiogenesis, vascular perfusion, and permeability. Three different cell-loaded collagen hydrogels (SHED-human umbilical vein endothelial cell [HUVEC], HUVEC with SHED-conditioned medium, and SHED alone) were cast in polylactic acid (PLA) grids and ectopically implanted in athymic mice. At day 10, in vivo positron emission tomography (PETscan) revealed a significantly increased uptake of radiotracer targeting activated endothelial cells in the SHED-HUVEC group compared to the other groups. At day 30, ex vivo micro-computed tomography imaging confirmed that SHED-HUVEC constructs had a significantly increased vascular volume compared to the other ones. Injection of species-specific lectins analyzed by 2-photon microscopy demonstrated blood perfusion of the engineered human vessels in both prevascularized groups. However, in vivo quantification showed increased vessel density in the SHED-HUVEC group. In addition, coinjection of fluorescent lectin and dextran revealed that prevascularization with SHED prevented vascular leakage, demonstrating the active role of SHED in the maturation of human-engineered microvascular networks. This preclinical study introduces a novel PLA prevascularized and implantable construct, along with an array of imaging techniques, to validate the ability of SHED to promote functional human-engineered vessels, further highlighting the interest of SHED for orofacial tissue engineering. Furthermore, this study validates the use of PETscan for the early detection of in vivo angiogenesis, which may be applied in the clinic to monitor the performance of prevascularized grafts., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: Introduced around the turn of the 21st century, silicone hydrogel contact lenses alleviated hypoxic anterior eye complications due to their high oxygen transmissibility. The purpose of this work is to update earlier surveys by describing international trends in silicone hydrogel daily wear contact lens fitting between 2000 and 2023., Method: An annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023. Data relating to 260,144 daily wear soft contact lens fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of silicone hydrogel daily wear contact lens fitting., Results: There has been a dramatic increase in silicone hydrogel daily wear lens fits (p < 0.0001), increasing from 2.8 % of all daily wear soft lens fits in 2000 to 73.7 % in 2023. Of all daily wear soft contact lenses prescribed to males, 44.6 % were silicone hydrogel lenses, compared with 43.5 % for females (p = 0.0146). The mean age of those wearing silicone hydrogel daily wear lenses was 32.0 ± 14.5 years, compared to 30.4 ± 13.6 years for those wearing daily wear hydrogel lenses (p < 0.0001). Between 2019-2023, the average percentage of fits was - (a) material type: silicone hydrogel - 73 %; mid-water content hydrogels - 13 %; high water content hydrogels - 9 %; and low water content hydrogels - 5 %, and (b) lens design: spherical - 44 %, toric - 32 %, multifocal - 17 %, monovision - 4 %, and 'other' - 3 %., Conclusion: The dramatic increase in silicone hydrogel contact lens prescribing for daily wear has been commensurate with the introduction of multiple lens brands and an ongoing expansion of lens designs, parameters and replacement frequency options. The balance between silicone hydrogel and hydrogel lens prescribing is perhaps starting to approach an equilibrium., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nathan Efron: Over the past three years Nathan Efron has received honoraria from CooperVision. Philip Morgan: Over the past three years Philip Morgan’s research group or he personally has received funding or honoraria from: Alcon, Bausch + Lomb, Clearlab, CooperVision, Daysoft, Johnson & Johnson Vision, mark’ennovy, Menicon, and Visco Vision. He is a director of M-Optometry Limited. Craig Woods: Over the past three years Craig Woods has acted as a consultant for the Brien Holden Vision Institute and Zeiss Vision Care. Deborah Jones: Over the past three years Debbie Jones has received honoraria from Hoya, Essilor, CooperVision, Alcon and SightGlass. Lyndon Jones: Over the past three years, Lyndon Jones’ research group (CORE) or he personally has received research support or lectureship honoraria from Alcon, Azura Ophthalmics, Bausch & Lomb, CooperVision, Essilor, Hoya, iMed Pharma, Integral Biosystems, Johnson & Johnson Vision, Menicon, Novartis, Ophtecs, Ote Pharma, Santen, SightGlass Vision, SightSage, Topcon and Visioneering. Dr Jones is also a consultant and/or serves on an advisory board for Alcon, CooperVision, Johnson & Johnson Vision, Novartis and Ophtecs. Jason Nichols: Jason Nichols has nothing to report. Also, Kelly Nichols is the spouse of Jason Nichols, extending her declarations to him. In the past 12 months, Kelly Nichols has consulted for and received honoraria from: Abbvie, Alcon, Aldeyra, Azura, Bausch + Lomb, Bruder, Cavalry, Dompe, HanAll Bio, Harrow, Novartis, Novaliq, Oyster Point Pharma/Viatris, Sydnexis, Tarsus, TearSolutions, Thea, Topcon, and Trukera. She has received research funding from: Aramis, Kowa, Science Based Health, Sylentis, and TearScience., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Renewable energy and advanced water treatment technologies hold profound significance for driving sustainable development in modern society. Given the environmental friendliness and high efficiency of electrocatalysis processes, great expectations are placed on their applications in energy and water-related fields. However, the electrocatalysis is limited by the selectivity, activity, and durability of the electrocatalytic reactions. Hydrogels, with their hierarchical porous structure, compositional and structural tunability, and ease of functionalization, are bringing surprising advances in advanced energy and environment. Hydrogel catalysts, inheriting the advantages of hydrogel materials, hold promise for achieving significant breakthroughs in electrochemical performance. Here, the latest advancements in energy and environmental electrocatalytic fields are summarized based on the 3D nanostructured hydrogel catalysts. In addition, future potentials and challenges of continuing research on hydrogel materials for energy and environment are discussed., (© 2024 Wiley‐VCH GmbH.)

The first report of star poly(L-proline) crosslinkers is disclosed for digital light processing 3D printing of thermoresponsive hydrogels. Through chain end functionalization of star poly(L-proline)s with methacryloyl groups, access to high-resolution defined 3D hydrogel structures via digital light processing is achieved through photoinitiated free radical polymerization. Changing the poly(L-proline) molecular weight has a direct influence on both thermoresponsiveness and printability, while shape-morphing behavior can be induced thermally., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Fungal infections can lead to debilitating consequences if they are not treated effectively. Antifungal drugs used to treat these infections can be toxic and overuse contributes to growing antifungal resistance. Candida spp., particularly C. albicans, are implicated in a majority of these infections. Virulent C. albicans produce secreted aspartic proteases (Saps) that aid in pathogen tissue invasion and proliferation at an infected site. Here, fungi-responsive hydrogels are developed that degrade in the presence of Saps to provide a triggered release of encapsulated liposomal antifungals. The hydrogel backbone incorporates a Sap-cleavable peptide sequence enabling Sap-responsive degradation. Hydrogels are found to effectively degrade in the presence of Saps extracted from C. albicans. Encapsulated liposomal antifungals show similar release kinetics as hydrogel degradation products in the presence of Saps, supporting a degradation-dependent release mechanism. Antifungal liposome-loaded responsive hydrogels exhibit successful eradication of C. albicans cultures and remain stable in sterile murine wound fluid. Finally, no significant cytotoxicity is observed for murine fibroblast cells and red blood cells exposed to hydrogel degradation products. These fungi-responsive hydrogels have the potential to be used for local, on-demand delivery of antifungal drugs, for effective treatment of fungal infections while helping to limit unnecessary exposure to these therapeutics., (© 2024 Wiley‐VCH GmbH.)

Infection is a major concern in surgery involving grafting and should be considered thoroughly when designing biomaterials. There is considerable renewed interest in silver nanoparticles (AgNPs) owing to their ability to potentiate antibacterial properties against multiple bacterial strains. This study aimed to develop two antibacterial bone regenerative scaffolds by integrating AgNPs in bovine bone particles (BBX) (Product 1), and a light cross-linked hydrogel GelMA (Product 2). The constructs were characterized using scanning electron microscopy. Metabolic activity of osteoblasts and osteoclasts on the constructs was investigated using PrestoBlue™. Disk diffusion assay was conducted to test the antibacterial properties. The regenerative capacity of the optimized AgNP functionalized BBX and GelMA were tested in a rabbit cranial 6 mm defect model. The presence of AgNPs appears to enhance proliferation of osteoblasts compared to AgNP free controls in vitro. We established that AgNPs can be used at a 100 μg dose that inhibits bacteria, with minimal adverse effects on the bone cells. Our rabbit model revealed that both the BBX and GelMA hydrogels loaded AgNPs were biocompatible with no signs of necrosis or inflammatory response. Grafts functionalized with AgNPs can provide antibacterial protection and simultaneously act as a scaffold for attachment of bone cells., (© 2024 The Author(s). Journal of Biomedical Materials Research Part A published by Wiley Periodicals LLC.)

Introduction: Managing large chronic wounds presents significant challenges because of inadequate donor sites, infection, and lack of structural support from dermal substitutes. Hydrogels are extensively used in various forms to promote chronic wound healing and provide a three-dimensional spatial structure, through growth factors or cell transport., Objectives: We present a novel multicenter regenerative model that is capable of regenerating and merging simultaneously to form a complete layer of skin. This method significantly reduces wound healing time compared to the traditional centripetal healing model. We believe that our model can improve clinical outcomes and pave the way for further research into regenerative medicine., Methods: We prepared a novel multi-island double-layer microneedle (MDMN) using gelatin-methacryloylchitosan (GelMA-CS). The MDMN was loaded with keratinocytes (KCs) and dermal fibroblasts (FBs). Our aim in this study was to explore the therapeutic potential of MDMN in a total skin excision model., Results: The MDMN model replicated the layered structure of full-thickness skin and facilitated tissue regeneration and healing via dual omni-bearing. Multi-island regeneration centres accomplished horizontal multicentric regeneration, while epidermal and dermal cells migrated synchronously from each location. This produced a healing area approximately 4.7 times greater than that of the conventional scratch tests. The MDMN model exhibited excellent antibacterial properties, attributed to the chitosan layer. During wound healing in diabetic mice, the MDMN achieved earlier epidermal coverage and faster wound healing through multi-island regeneration centres and the omnidirectional regeneration mode. The MDMN group displayed an accelerated wound healing rate upon arrival at the destination (0.96 % ± 0.58 % vs. 4.61 % ± 0.32 %). Additionally, the MDMN group exhibited superior vascularization and orderly collagen deposition., Conclusion: The present study presents a novel skin regeneration model using microneedles as carriers of autologous keratinocytes and dermal fibroblasts, which allows for omni-directional, multi-center, and full-thickness skin regeneration., 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 © 2023. Published by Elsevier B.V.)

Due to repeated microbial infection, persistent inflammation, excessive oxidative stress, and cell dysfunction, chronic wounds are difficult to heal, posing a serious threat to public health. Therefore, developing multifunctional wound dressings that can regulate the complex microenvironment of chronic wounds and enhance cellular function holds great significance. Recently, chitosan has emerged as a promising biopolymer for wound healing due to its excellent biocompatibility, biodegradability, and versatile bioactivity. The aim of this review is to provide a comprehensive understanding of the mechanisms of delayed chronic wound healing and discuss the healing-promoting properties of chitosan and its derivatives, such as good biocompatibility, antibacterial activity, hemostatic capacity, and the ability to promote tissue regeneration. On this basis, the potential applications of chitosan-based hydrogels are summarized in chronic wound healing, including providing a suitable microenvironment, eliminating bacterial infections, promoting hemostasis, inhibiting chronic inflammation, alleviating oxidative stress, and promoting tissue regeneration. In addition, the concerns and perspectives for the clinical application of chitosan-based hydrogels are also discussed., (© 2024 Wiley‐VCH GmbH.)