Self-Healable Antifouling Zwitterionic Hydrogel Based on Synergistic Phototriggered Dynamic Disulfide Metathesis Reaction and Ionic Interaction

Perceiving and Countering Marine Biofouling: Structure, Forces, and Processes at Surfaces in Sea Water Across the Length Scales

In marine industries, severe economic losses are caused by accumulating organisms on surfaces in biofouling processes. Establishing a universal and nontoxic protocol to eliminate biofouling has been a notoriously difficult task due to the complexity of the marine organisms' interactions with surfaces and the chemical, mechanical, and morphological diversity of the surfaces involved. The tremendous variety of environmental parameters in marine environments further complicates this field. For efficient surface engineering to combat fouling, secretion, chemical structure, and properties of biobased adhesives and adhesion mechanisms must be understood. Advanced characterization techniques, like Atomic Force Microscopy (AFM), now allow one to study the three parameters determining surface adhesion and, eventually, fouling, i.e., morphology, chemistry, and surface mechanical modulus. By AFM, characterization can now be performed across length scales from nanometers to hundreds of micrometers. This review provides an up-to-date account of the most promising AFM-based approaches for imaging and characterizing natural adhesives provided by marine organisms. We summarize the current understanding of the molecular basis and the related relevant processes of marine fouling. We focus on applications of AFM "beyond imaging", i.e., to study interactions between adhesives and the surfaces involved. Additionally, we discuss the performance enhancement of polymer antifouling coatings using information derived from AFM. Knowledge and control of marine adhesion can be applied to prevent marine fouling, as well as to design bioadhesives to enhance potential medical applications. We present some milestone results and conclude with an outlook discussing novel possibilities for designing antifouling coatings and medical bioadhesives.

Innovative technologies for the fabrication of 3D/4D smart hydrogels and its biomedical applications - A comprehensive review

Repairing and regenerating damaged tissues or organs, and restoring their functioning has been the ultimate aim of medical innovations. 'Reviving healthcare' blends tissue engineering with alternative techniques such as hydrogels, which have emerged as vital tools in modern medicine. Additive manufacturing (AM) is a practical manufacturing revolution that uses building strategies like molding as a viable solution for precise hydrogel manufacturing. Recent advances in this technology have led to the successful manufacturing of hydrogels with enhanced reproducibility, accuracy, precision, and ease of fabrication. Hydrogels continue to metamorphose as the vital compatible bio-ink matrix for AM. AM hydrogels have paved the way for complex 3D/4D hydrogels that can be loaded with drugs or cells. Bio-mimicking 3D cell cultures designed via hydrogel-based AM is a groundbreaking in-vivo assessment tool in biomedical trials. This brief review focuses on preparations and applications of additively manufactured hydrogels in the biomedical spectrum, such as targeted drug delivery, 3D-cell culture, numerous regenerative strategies, biosensing, bioprinting, and cancer therapies. Prevalent AM techniques like extrusion, inkjet, digital light processing, and stereo-lithography have been explored with their setup and methodology to yield functional hydrogels. The perspectives, limitations, and the possible prospects of AM hydrogels have been critically examined in this study.

Self-Healing Hydrogel Bioelectronics

Hydrogels have emerged as powerful building blocks to develop various soft bioelectronics because of their tissue-like mechanical properties, superior bio-compatibility, the ability to conduct both electrons and ions, and multiple stimuli-responsiveness. However, hydrogels are vulnerable to mechanical damage, which limits their usage in developing durable hydrogel-based bioelectronics. Self-healing hydrogels aim to endow bioelectronics with the property of repairing specific functions after mechanical failure, thus improving their durability, reliability, and longevity. This review discusses recent advances in self-healing hydrogels, from the self-healing mechanisms, material chemistry, and strategies for multiple properties improvement of hydrogel materials, to the design, fabrication, and applications of various hydrogel-based bioelectronics, including wearable physical and biochemical sensors, supercapacitors, flexible display devices, triboelectric nanogenerators (TENGs), implantable bioelectronics, etc. Furthermore, the persisting challenges hampering the development of self-healing hydrogel bioelectronics and their prospects are proposed. This review is expected to expedite the research and applications of self-healing hydrogels for various self-healing bioelectronics.

Construction of a Soft Antifouling PAA/PSBMA Hydrogel Coating with High Toughness and Low Swelling through the Dynamic Coordination Bonding Provided by Al(OH)3 Nanoparticles

Marine biofouling, resulting from the adhesion of marine organisms to ship surfaces, has long been a significant issue in the maritime industry. In this paper, we focused on utilizing soft and hydrophilic hydrogels as a potential approach for antifouling (AF) coatings. Acrylic acid (AA) with a polyelectrolyte effect and N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine (SBMA) with an antipolyelectrolyte effect were selected as monomers. By adjusting the monomer ratio, we were able to create hydrogel coatings that exhibited low swelling ratio in both fresh water and seawater. The Al(OH)3 nanoparticle, as a physical cross-linker, provided better mechanical properties (higher tensile strength and larger elongation at break) than the chemical cross-linker through the dynamic coordination bonds and plentiful hydrogen bonds. Additionally, we incorporated trehalose into the hydrogel, enabling the repair of the hydrogel network through covalent-like hydrogen bonding. The zwitterion compound SBMA endowed the hydrogel with excellent AF performance. It was found that the highest SBMA content did not lead to the best antibacterial performance, as bacterial adhesion quantity was also influenced by the charge of the hydrogel. The hydrogel with appropriate SBMA content being close to electrical neutrality exhibits the strongest zwitterionic property of PSBMA chains, resulting in the best antibacterial adhesion performance. Furthermore, the pronounced hydrophilicity of SBMA enhanced the lubrication of the hydrogel surface, thereby reducing the friction resistance when applied to the hull surface during ship navigation.

Synergistic strengthening of PVA ionic conductive hydrogels using aramid nanofibers and tannic acid for mechanically robust, antifreezing, water-retaining and antibacterial flexible sensors

Ion-conductive hydrogels with multi-functionality have gained significant attraction as flexible sensors in various fields such as wearable health monitoring and human motion detection, owing to their high ion conductivity, excellent flexibility and stretchability, and easy availability. In this work, multifunctional ion-conductive hydrogel with excellent mechanical properties, antifreezing properties, water retention and antibacterial performance was fabricated by the freeze-thaw crosslinking between polyvinyl alcohol (PVA) and aramid nanofibers (ANF), and the subsequent solution immersion crosslinking in a mixture of tannic acid (TA) and CaCl2 solution (DMSO/H2O as co-solvent). The rational engineering of a multi-spatial distributed hydrogen bond and Ca2+ coordination bond networks within the hydrogel led to a significant improvement in mechanical properties. Furthermore, through the introduction of TA and binary solvents (DMSO/H2O), the hydrogel had witnessed a substantial enhancement in its antimicrobial properties and water retention capacity. The resultant PAT5/CaCl2-5% (DMSO/H2O) hydrogel exhibited outstanding elongation at break (754.73%), tensile strength (6.25 MPa), electrical conductivity (3.09 S/m), which can be employed in flexible sensors to monitor real-time functional motion for human under diverse conditions. As such, this innovation opens up a novel pathway for envisioning flexible sensor devices, particularly in the realm of human activity monitoring.

Current Self-Healing Binders for Energetic Composite Material Applications

Energetic composite materials (ECMs) are the basic materials of polymer binder explosives and composite solid propellants, which are mainly composed of explosive crystals and binders. During the manufacturing, storage and use of ECMs, the bonding surface is prone to micro/fine cracks or defects caused by external stimuli such as temperature, humidity and impact, affecting the safety and service of ECMs. Therefore, substantial efforts have been devoted to designing suitable self-healing binders aimed at repairing cracks/defects. This review describes the research progress on self-healing binders for ECMs. The structural designs of these strategies to manipulate macro-molecular and/or supramolecular polymers are discussed in detail, and then the implementation of these strategies on ECMs is discussed. However, the reasonable configuration of robust microstructures and effective dynamic exchange are still challenges. Therefore, the prospects for the development of self-healing binders for ECMs are proposed. These critical insights are emphasized to guide the research on developing novel self-healing binders for ECMs in the future.

Green Hydrogel Synthesis: Emphasis on Proteomics and Polymer Particle-Protein Interaction

The field of drug discovery has seen significant progress in recent years. These advances drive the development of new technologies for testing compound's effectiveness, as well as their adverse effects on organs and tissues. As an auxiliary tool for drug discovery, smart biomaterials and biopolymers produced from biodegradable monomers allow the manufacture of multifunctional polymeric devices capable of acting as biosensors, of incorporating bioactives and biomolecules, or even mimicking organs and tissues through self-association and organization between cells and biopolymers. This review discusses in detail the use of natural monomers for the synthesis of hydrogels via green routes. The physical, chemical and morphological characteristics of these polymers are described, in addition to emphasizing polymer-particle-protein interactions and their application in proteomics studies. To highlight the diversity of green synthesis methodologies and the properties of the final hydrogels, applications in the areas of drug delivery, antibody interactions, cancer therapy, imaging and biomarker analysis are also discussed, as well as the use of hydrogels for the discovery of antimicrobial and antiviral peptides with therapeutic potential.

Self-Healing Silsesquioxane-Based Materials

This review is devoted to self-healing materials (SHM) containing polyhedral oligomeric silsesquioxanes (POSS) as building blocks. The synthetic approach can vary depending on the role POSS are expected to play in a given system. POSS (especially double-decker silsesquioxanes) can be grafted in side chains of a polymer backbone or used as segments of the main chain. Appropriate functionalization allows the formation of dynamic bonds with POSS molecules and makes them an active component of SHM, both as crosslinking agents and as factors that enhance the dynamics of macromolecules in the polymer matrix. The latter effect can be achieved by reversible release of bulky POSS cages or by the formation of separated inclusions in the polymer matrix through hydrophobic interactions and POSS aggregation. The unique properties of POSS-based self-healing systems make them interesting and versatile materials for various applications (e.g., repairable coatings, sealants, sensors, soft materials for tissue engineering, drug delivery, and wound healing).

Motion Detecting, Temperature Alarming, and Wireless Wearable Bioelectronics Based on Intrinsically Antibacterial Conductive Hydrogels

Hydrogels have attracted considerable interest in developing flexible bioelectronics such as wearable devices, brain-machine interface products, and health-monitoring sensors. However, these bioelectronics are always challenged by microbial contamination, which frequently reduces their service life and durability due to a lack of antibacterial property. Herein, we report a class of inherently antibacterial conductive hydrogels (ACGs) as bioelectronics for motion and temperature detection. The ACGs were composed of poly(N-isopropylacrylamide) (pNIPAM) and silver nanowires (AgNWs) via a two-step polymerization strategy, which increased the crosslink density for enhanced mechanical properties. The introduction of AgNWs improved the conductivity of ACGs and endowed them with excellent antibacterial activity against both Gram-positive and -negative bacteria. Meanwhile, pNIPAM existed in ACGs and exhibited a thermal responsive behavior, thereby inducing sharp changes in their conductivity around body temperature, which was successfully employed to assemble a temperature alarm. Moreover, ACG-based sensors exhibited excellent sensitivity (within a small strain of 5%) and the capability of capturing various motion signals (finger bending, elbow bending, and even throat vibrating). Benefiting from the superiority of ACG-based sensors, we further demonstrated a wearable wireless system for the remote control of a vehicle, which is expected to help disabled people in the future.

Recent advancement in Bi5O7I-based nanocomposites for high performance photocatalysts

Bi₅O₇I belongs to the family of bismuth oxyhalides (BiOX, X = Cl, Br, I), having a unique layered structure with an internal electrostatic field that promotes the separation and transfer of photo-generated charge carriers. Interestingly, Bi₅O₇I exhibits higher thermal stability compared to its other BiOX member compounds and absorption spectrum extended to the visible region. Bi₅O₇I has demonstrated applications in diverse fields such as photocatalytic degradation of various organic pollutants, marine antifouling, etc. Unfortunately, owing to its wide band gap of ∼2.9 eV, its absorption lies mainly in the ultraviolet region, and a tiny portion of absorption lies in the visible region. Due to limited absorption, the photocatalytic performance of pure Bi₅O₇I is still facing challenges. In order to reduce the band gap and increase the light absorption capability of Bi₅O₇I, doping and formation of heterostructure strategies have been employed, which showed promising results in the photocatalytic performance. In addition, the plasmonic heterostructures of Bi₅O₇I were also developed to further boost the efficiency of Bi₅O₇I as a photocatalyst. Here, in this review article, we present such recent efforts made for the advanced development of Bi₅O₇I regarding its synthesis, properties and applications. The strategies for photocatalytic performance enhancement have been discussed in detail. Moreover, in the conclusion section, we have presented the current challenges and discussed possible prospective developments in this field.

Controlling Properties and Functions of Polymer Gels Using Photochemical Reactions

Photoresponsive polymer gels have attracted increasing interest owing to their potential applications in healable materials, drug release systems, and extracellular matrices. Because polymer gels provide suitable environments for photochemical reactions, their properties and functions can be controlled with light with a high spatiotemporal resolution. Herein, the design of photoresponsive polymer gels based on different types of photochemical reactions is introduced. The mechanism and applications of irreversible photoreactions, such as photoinduced free-radical polymerization, photoinduced click reactions, and photolysis, as well as reversible photoreactions such as photoinduced reversible cycloadditions, reversible photosubstitution of metal complexes, and photoinduced metathesis are reviewed. The remaining challenges of photoresponsive polymer gels are also discussed.

Light manipulation for fabrication of hydrogels and their biological applications

The development of biocompatible materials with desired functions is essential for tissue engineering and biomedical applications. Hydrogels prepared from these materials represent an important class of soft matter for mimicking extracellular environments. In particular, dynamic hydrogels with responsiveness to environments are quite appealing because they can match the dynamics of biological processes. Among the external stimuli that can trigger responsive hydrogels, light is considered as a clean stimulus with high spatiotemporal resolution, complete bioorthogonality, and fine tunability regarding its wavelength and intensity. Therefore, photoresponsiveness has been broadly encoded in hydrogels for biological applications. Moreover, light can be used to initiate gelation during the fabrication of biocompatible hydrogels. Here, we present a critical review of light manipulation tools for the fabrication of hydrogels and for the regulation of physicochemical properties and functions of photoresponsive hydrogels. The materials, photo-initiated chemical reactions, and new prospects for light-induced gelation are introduced in the former part, while mechanisms to render hydrogels photoresponsive and their biological applications are discussed in the latter part. Subsequently, the challenges and potential research directions in this area are discussed, followed by a brief conclusion. STATEMENT OF SIGNIFICANCE: Hydrogels play a vital role in the field of biomaterials owing to their water retention ability and biocompatibility. However, static hydrogels cannot meet the dynamic requirements of the biomedical field. As a stimulus with high spatiotemporal resolution, light is an ideal tool for both the fabrication and operation of hydrogels. In this review, light-induced hydrogelation and photoresponsive hydrogels are discussed in detail, and new prospects and emerging biological applications are described. To inspire more research studies in this promising area, the challenges and possible solutions are also presented.

Synthesis, classification and properties of hydrogels: their applications in drug delivery and agriculture

Absorbent polymers or hydrogel polymer materials have an enhanced water retention capacity and are widely used in agriculture and medicine. The controlled release of bioactive molecules (especially drug proteins) by hydrogels and the encapsulation of living cells are some of the active areas of drug discovery research. Hydrogel-based delivery systems may result in a therapeutically advantageous outcome for drug delivery. They can provide various sequential therapeutic agents including macromolecular drugs, small molecule drugs, and cells to control the release of molecules. Due to their controllable degradability, ability to protect unstable drugs from degradation and flexible physical properties, hydrogels can be used as a platform in which various chemical and physical interactions with encapsulated drugs for controlled release in the system can be studied. Practically, hydrogels that possess biodegradable properties have aroused greater interest in drug delivery systems. The original three-dimensional structure gets broken down into non-toxic substances, thus confirming the excellent biocompatibility of the gel. Chemical crosslinking is a resource-rich method for forming hydrogels with excellent mechanical strength. But in some cases the crosslinker used in the synthesis of the hydrogels may cause some toxicity. However, the physically cross-linked hydrogel preparative method is an alternative solution to overcome the toxicity of cross-linkers. Hydrogels that are responsive to stimuli formed from various natural and synthetic polymers can show significant changes in their properties under external stimuli such as temperature, pH, light, ion changes, and redox potential. Stimulus-responsive hydrogels have a wider range of applications in biomedicine including drug delivery, gene delivery and tissue regeneration. Stimulus-responsive hydrogels loaded with multiple drugs show controlled and sustained drug release and can act as drug carriers. By integrating stimulus-responsive hydrogels, such as those with improved thermal responsiveness, pH responsiveness and dual responsiveness, into textile materials, advanced functions can be imparted to the textile materials, thereby improving the moisture and water retention performance, environmental responsiveness, aesthetic appeal, display and comfort of textiles. This review explores the stimuli-responsive hydrogels in drug delivery systems and examines super adsorbent hydrogels and their application in the field of agriculture.

Zwitterionic Nanocapsules with Salt- and Thermo-Responsiveness for Controlled Encapsulation and Release

Intelligent polymer nanocapsules that can not only encapsulate substances efficiently but also release them in a controllable manner hold great potential in many applications. To date, although intensive efforts have been made to develop intelligent polymer nanocapsules, how to construct the well-defined core/shell structure with high stability via a straightforward method remains a considerable challenge. In this work, the target novel zwitterionic nanocapsules (ZN_Cs) with a stable hollow structure were synthesized by inverse reversible addition fragmentation transfer (RAFT) miniemulsion interfacial polymerization. The shell gradually grew from the water/oil interface due to the interfacial polymerization, accompanied by the cross-linking of the polyzwitterionic networks, where the core/shell structure could be well-tuned by adjusting the precursor compositions. The resultant ZN_Cs exhibited a salt-/thermo-induced swelling behavior through the phase transition of the external zwitterionic polymers. To further investigate the functions of ZN_Cs, different substances, such as methyl orange and bovine serum albumin (BSA), were encapsulated into the ZN_Cs with a high encapsulation efficiency of 89.3 and 93.6%, respectively. Interestingly, the loaded substances can be controllably released in aqueous solution triggered by salt or temperature variations, and such responsiveness also can be utilized to bounce off the bacteria adhered on target surfaces. We believe that these designed salt- and thermo-responsive intelligent polymer nanocapsules with well-defined core/shell structures and antifouling surfaces should be a promising platform for biomedical and saline related applications.

Nanogels: A novel approach in antimicrobial delivery systems and antimicrobial coatings

The implementation of nanotechnology to develop efficient antimicrobial systems has a significant impact on the prospects of the biomedical field. Nanogels are soft polymeric particles with an internally cross-linked structure, which behave as hydrogels and can be reversibly hydrated/dehydrated (swollen/shrunken) by the dispersing solvent and external stimuli. Their excellent properties, such as biocompatibility, colloidal stability, high water content, desirable mechanical properties, tunable chemical functionalities, and interior gel-like network for the incorporation of biomolecules, make them fascinating in the field of biological/biomedical applications. In this review, various approaches will be discussed and compared to the newly developed nanogel technology in terms of efficiency and applicability for determining their potential role in combating infections in the biomedical area including implant-associated infections.

Self-healable hydrophobic polymer material having urethane linkages via a non-isocyanate route and dynamic Diels-Alder 'click' reaction

Conventional synthesis of polyurethane (PU) often involves the use of inherently toxic and overly moisture-sensitive isocyanates. Herein, we report the preparation of a self-healable hydrophobic polymer network having urethane linkages via a facile non-isocyanate route based on carbonylimidazole-amine reaction and dynamic Diels-Alder (DA) 'click' reaction based on furan-maleimide cycloaddition. This isocyanate-free DA 'clicked' polymer material showed excellent self-healing and hydrophobic characteristics.

Self-healing hydrophobic POSS-functionalized fluorinated copolymers via RAFT polymerization and dynamic Diels–Alder reaction

Development of self-healing hydrophobic POSS-functionalized fluorinated copolymethacrylate(s) via RAFT Polymerization and dynamic Diels–Alder Reaction.

Synthesis of zwitterionic chimeric polymersomes for efficient protein loading and intracellular delivery

Design and synthesis of degradable chimeric polymersomes based on zwitterionic PAC(DMA)-PCL-PMDMSA triblock copolymers for high protein loading and intracellular delivery.

A novel dual crosslinked polysaccharide hydrogel with self-healing and stretchable properties

We synthesized oxidatively modified acetoacetyl cellulose OCAA, and then a double-network polysaccharide complex hydrogel was prepared. The hydrogel exhibited very good mechanical strength, self-healing behavior, and good biocompatibility.

Construction of a thermoreversible chemical crosslinking network – a new exploration for the efficient reusability of commercial rubber

A thermoreversible rubber DSBR was prepared via a reaction between a nitroxide-based crosslinker and commercial styrene–butadiene rubber. Impressive recoveries of mechanical properties of DSBR were achieved for the alkoxyamine crosslinking network.

Stimuli-Responsive Zwitterionic Core-Shell Microgels for Antifouling Surface Coatings

Fouling on filtration membranes is induced by the nonspecific interactions between the membrane surface and the foulants, and effectively hinders their efficient use in various applications. Here, we established a facile method for the coating of membrane surface with a dual stimuli-responsive antifouling microgel system enriched with a high polyzwitterion content. Different poly(sulfobetaine) (PSB) zwitterionic polymers with defined molecular weights and narrow dispersities were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and integrated onto poly(N-vinylcaprolactam) (PVCL) microgels via a controlled dosage of a cross-linker, adapting a precipitation polymerization technique to obtain a core-shell microstructure. Increasing the PSB macro-RAFT concentration resulted in a shift of both upper critical solution temperature and lower critical solution temperature toward higher temperatures. Cryogenic transmission electron microscopy at different temperatures suggested the formation of a core-shell morphology with a PVCL-rich core and a PSB-rich shell. On the other hand, the significant variations of different characteristic proton signals and reversible phase transitions of the microgel constituents were confirmed by temperature-dependent ¹H NMR studies. Utilizing a quartz crystal microbalance with dissipation monitoring, we have been able to observe and quantitatively describe the antipolyelectrolyte behavior of the zwitterionic microgels. The oscillation frequency of the sensor proved to change reversibly according to the variations of the NaCl concentration, showing, in fact, the effect of the interaction between the salt and the opposite charges present in the microgel deposited on the sensor. Poly(ethersulfone) membranes, chosen as the model surface, when functionalized with zwitterionic microgel coatings, displayed protein-repelling property, stimulated by different transition temperatures, and showed even better performances at increasing NaCl concentration. These kinds of stimuli-responsive zwitterionic microgel can act as temperature-triggered drug delivery systems and as potential coating materials to prevent bioadhesion and biofouling as well.

Honey-inspired antimicrobial hydrogels resist bacterial colonization through twin synergistic mechanisms

Inspired by the interesting natural antimicrobial properties of honey, biohybrid composite materials containing a low-fouling polymer hydrogel network and an encapsulated antimicrobial peroxide-producing enzyme have been developed. These synergistically combine both passive and active mechanisms for reducing microbial bacterial colonization. The mechanical properties of these materials were assessed using compressive mechanical analysis, which revealed these hydrogels possessed tunable mechanical properties with Young's moduli ranging from 5 to 500 kPa. The long-term enzymatic activities of these materials were also assessed over a 1-month period using colorimetric assays. Finally, the passive low-fouling properties and active antimicrobial activity against a leading opportunistic pathogen, Staphylococcus epidermidis, were confirmed using bacterial cell counting and bacterial adhesion assays. This study resulted in non-adhesive substrate-permeable antimicrobial materials, which could reduce the viability of planktonic bacteria by greater than 7 logs. It is envisaged these new biohybrid materials will be important for reducing bacterial adherence in a range of industrial applications.

Fatigue-Resistant, Notch-Insensitive Zwitterionic Polymer Hydrogels with High Self-Healing Ability

Introducing self-healing properties into hydrogels can prolong their application lifetime. However, achieving mechanical strength without sacrificing self-healing properties is still a major challenge. We prepared a series of zwitterionic polymer hydrogels by random copolymerization of zwitterionic ionic monomer (SBMA), cationic monomer (DAC) and hydrophilic monomer (HEMA). The ionic bonds and hydrogen bonds formed in the hydrogels can efficiently dissipate energy and rebuild the network. The resulting hydrogels show high mechanical strength (289-396 KPa of fracture stress, 433-864 % of fracture stress) and have great fatigue resistance. The hydrogel with a 1 : 1 molar ratio of SBMA:DAC possesses the best self-healing properties (self-healing efficiency up to 96.5 % at room temperature for 10 h). The self-healing process is completely spontaneous and does not require external factors to assist. In addition, the hydrogel also possesses notch insensitivity with a fracture energy of 12000 J m^-2 . After combining the conductivity of RGO aerogel, the hydrogel/RGO composites show good strain sensitivity with high reliability and self-healing ability, which has certain significance in broadening the application of these zwitterionic hydrogels.

Conductive Hydrogels-A Novel Material: Recent Advances and Future Perspectives

A conductive hydrogel is a kind of polymer material having substantial potential applications with various properties, including high toughness, self-recoverability, electrical conductivity, transparency, freezing resistance, stimuli responsiveness, stretchability, self-healing, and strain sensitivity. Herein, according to the current research status of conductive hydrogels, properties of conductive hydrogels, preparation methods of different conductive hydrogels, and their application in different fields, such as sensor and actuator fabrication, biomedicine, and soft electronics, are introduced. Furthermore, the development direction and application prospects of conductive hydrogels are proposed.

A novel xanthan gum-based conductive hydrogel with excellent mechanical, biocompatible, and self-healing performances

Tough and conductive hydrogels are promising materials for various applications. However, it remains a great challenge to develop an integrated hydrogel combining outstanding mechanical, conductive, and self-healing performances. Herein, we prepared a conductive, self-healing, and tough hydrogel by constructing synergistic multiple interaction among montmorillonite (MMT), Poly (acrylamide-co-acrylonitrile) (P(AAm-co-AN)), xanthan gum (XG) and ferric ion (Fe³⁺). The obtained xanthan gum/montmorillonite/Poly (acrylamide-co-acrylonitrile) (XG/MMT/PAAm) hydrogels showed high strain stress (0.48 MPa) and compressive stress (5.9 MPa) as well as good shape recovery after multiple loading-unloading cycle tests. Moreover, the XG/MMT/PAAm hydrogels have distinctive features such as remarkable resistance to fatigue and harsh environments, insensitivity to notch, conductive, biocompatible, pH-dependent swelling behaviors and self-healing. Therefore, the as-fabricated hydrogel delivers a new prospect for its applications in various fields, such as flexible conductive device and tissue engineering.

Three-dimensional flower-like shaped Bi5O7I particles incorporation zwitterionic fluorinated polymers with synergistic hydration-photocatalytic for enhanced marine antifouling performance

Herein, several novel composite films consisting of three-dimensional (3D) Bi₅O₇I flower-like shaped microsphere and zwitterionic fluorinated polymer (ZFP) were successfully fabricated with the aim of achieving high anti-fouling performance. The prepared Bi₅O₇I flower-like shaped microsphere particles with diameters in the range of 2∼3 μm were uniformly distributed on the surface and in the internal of ZFP. Benefiting from the hydration layer formed by the ZFP and the efficient photocatalytic performance of Bi₅O₇I flower-like microsphere, the resultant optimized Bi₅O₇I/ZFP composite film exhibited an excellent diatom anti-settling performance and a high antibacterial rate of 99.09% and 99.66% towards Escherichia coli and Staphylococcus aureus. In addition, the composite films possessed the strengthened visible light absorption, the effectively separation and transfer of the photo-induced electrons and holes, the large number of hydroxyl (OH) radicals and superoxide radicals (O₂^-) all in Bi₅O₇I/ZFP systems, all of which were beneficial for the photocatalytic antifouling activity. More importantly, the synergistic hydration-photocatalytic effect of the Bi₅O₇I/ZFP composite films are answerable for the improvement of the antifouling property compared to the control. Thus, the synergistic hydration-photocatalytic contribution of Bi₅O₇I/ZFP composite film will shows promise for potential application in marine antifouling.

A self-healable and antifouling hydrogel based on PDMS centered ABA tri-block copolymer polymersomes: a potential material for therapeutic contact lenses

We have prepared an antifouling and self-healable PDMS based hydrogel which consists of a mixture of curcumin loaded zwitterionic PDMS polymersomes and amine functionalized PDMS polymersomes prepared via RAFT polymerization and Schiff-base reaction.

Design and Applications of Photoresponsive Hydrogels

Hydrogels are the most relevant biochemical scaffold due to their tunable properties, inherent biocompatibility, and similarity with tissue and cell environments. Over the past decade, hydrogels have developed from static materials to "smart" responsive materials adapting to various stimuli, such as pH, temperature, chemical, electrical, or light. Light stimulation is particularly interesting for many applications because of the capability of contact-free remote manipulation of biomaterial properties and inherent spatial and temporal control. Moreover, light can be finely adjusted in its intrinsic properties, such as wavelength and intensity (i.e., the energy of an individual photon as well as the number of photons over time). Water is almost transparent for light in the photochemically relevant range (NIR-UV), thus hydrogels are well-suited scaffolds for light-responsive functionality. Hydrogels' chemical and physical variety combined with light responsiveness makes photoresponsive hydrogels ideal candidates for applications in several fields, ranging from biomaterials, medicine to soft robotics. Herein, the progress and new developments in the field of light-responsive hydrogels are elaborated by first introducing the relevant photochemistries before discussing selected applications in detail.

Using Synergistic Multiple Dynamic Bonds to Construct Polymers with Engineered Properties

Dynamic bonds have achieved significant attention for their ability to impart fascinating properties to polymeric materials, such as high mechanical strength, self-healing, shape memory, 3D printability, and conductivity. Incorporating multiple dynamic bonds into polymer systems affords an attractive and efficient approach to endow multiple functionalities. This mini-review focuses on the use of complementary dynamic interactions to control the properties of soft materials. Owing to the diversity in dynamic chemistries that can be explored, the scope of this article is restricted to polymers and does not include colloids, amphiphiles, liquid crystals, or biological soft matter.