Hydrogel Matrix Research Articles

Interfacial charge demulsification endowed dual-network photocatalytic hydrogen-bonded PVA@agarose membranes for oil-water separation

Hydrogel materials with hydrophilic cross-linked network exhibit remarkable super-wettability, enabling their widespread application in oily wastewater treatment. However, the single and loose structure lacks sufficient strength and porosity to resist long-term degradation. Herein, a structural synergistic molecular strategy was reported to introduce reinforcing phase structures and interfacial active sites into the polymer networks for long-term oil-water emulsion separation. The carbon skeleton was uniformly interspersed through the strongly hydrogen-bonded polymer chains via covalent bonds, resulting in a hydrogel network with high mechanical strength and exceptional flow conductivity, which maintained a separation flux of 1233 L m−2 h−1 after 20 separation cycles under gravitational force. Dense negative charges on the surface disrupted the internal charge stability of the oil-water emulsion, leading to remarkable demulsification with a separation efficiency exceeding 99 %. Simultaneously, the strong redox reaction of the photoheterojunction effectively removed organic dyes under visible light, enhancing the overall antifouling performance. This study provided a feasible strategy at the molecular level for optimizing the suitability of hydrogels for oil-water emulsion separation.

Preparation and properties of biomimetic bone repair hydrogel with sandwich structure.

One of the critical factors that determines the biological properties of scaffolds is their structure. Due to the mechanical and structural discrepancies between the target bone and implants, the poor internal architecture design and difficulty in degradation of conventional bone implants may cause several adverse outcomes. To date, many scaffolds, such as 3-D printed sandwich structures, have been successfully developed for the repair of bone defects; however, the steps of these methods are complex and costly. Hydrogels have emerged as a unique scaffold material for repairing bone defects because of their good biocompatibility and excellent physicochemical properties. However, studies exploring bioinspired hydrogel scaffolds with hierarchical structures are scarce. More efforts are needed to incorporate bioinspired structures into hydrogel scaffolds to achieve optimal osteogenic properties. In this study, we developed a low-cost and easily available hydrogel matrix that mimicked the natural structure of the bone's porous sandwich to promote new bone growth and tissue integration. A comprehensive evaluation was conducted on the microstructure, swelling rate, and mechanical properties of this hydrogel. Furthermore, a 3D finite element analysis was employed to model the structure-property relationship. The results indicate that the sandwich-structured hydrogel is a promising scaffold material for bone injury repair, exhibiting enhanced compressive stress, elastic modulus, energy storage modulus, and superior force transmission.

Injectable, reversibly thermoresponsive captopril-laden hydrogel for the local treatment of sensory loss in diabetic neuropathy

A major and irreversible complication of diabetes is diabetic peripheral neuropathy (DPN), which can lead to significant disability and decreased quality of life. Prior work demonstrates the peptide hormone Angiotensin II (Ang II) is released locally in neuropathy and drives inflammation and impaired endoneurial blood flow. Therefore, we proposed that by utilizing a local thermoresponsive hydrogel injection, we could deliver inhibitors of angiotensin-converting enzyme (ACE) to suppress Ang II production and reduce nerve dysfunction in DPN through local drug release. The ACE inhibitor captopril was encapsulated into a micelle, which was then embedded into a reversibly thermoresponsive pluronics-based hydrogel matrix. Drug-free and captopril-loaded hydrogels demonstrated excellent product stability and sterility. Rheology testing confirmed sol properties with low viscosity at ambient temperature and increased viscosity and gelation at 37 °C. Captopril-loaded hydrogels significantly inhibited Ang II production in comparison to drug-free hydrogels. DPN mice treated with captopril-loaded hydrogels displayed normalized mechanical sensitivity and reduced inflammation, without side-effects associated with systemic exposure. Our data demonstrate the feasibility of repurposing ACE inhibitors as locally delivered anti-inflammatories for the treatment of sensory deficits in DPN. To the best of our knowledge, this is the first example of a locally delivered ACE inhibitor for the treatment of DPN.

Hydrogels and Aerogels for Versatile Photo-/Electro-Chemical and Energy-Related Applications.

The development of photo-/electro-chemical and flexible electronics has stimulated research in catalysis, informatics, biomedicine, energy conversion, and storage applications. Gels (e.g., aerogel, hydrogel) comprise a range of polymers with three-dimensional (3D) network structures, where hydrophilic polyacrylamide, polyvinyl alcohol, copolymers, and hydroxides are the most widely studied for hydrogels, whereas 3D graphene, carbon, organic, and inorganic networks are widely studied for aerogels. Encapsulation of functional species with hydrogel building blocks can modify the optoelectronic, physicochemical, and mechanical properties. In addition, aerogels are a set of nanoporous or microporous 3D networks that bridge the macro- and nano-world. Different architectures modulate properties and have been adopted as a backbone substrate, enriching active sites and surface areas for photo-/electro-chemical energy conversion and storage applications. Fabrication via sol-gel processes, module assembly, and template routes have responded to professionalized features and enhanced performance. This review presents the most studied hydrogel materials, the classification of aerogel materials, and their applications in flexible sensors, batteries, supercapacitors, catalysis, biomedical, thermal insulation, etc.

Different approaches and role of dinoprostone vaginal insert in induction of labour

Prostaglandin E2 (PGE2) plays a crucial role in cervical ripening and initiating parturition. The Dinoprostone vaginal insert, containing 10 mg of Dinoprostone within a polymeric hydrogel matrix, ensures controlled and consistent release. In women with intact membranes, the release rate averages 0.3 mg per hour, while in those with premature rupture of membranes, variability may occur. Compared to Dinoprostone gel, the insert significantly increases the likelihood of achieving vaginal delivery within 24 hours, with shorter hospital stays and reduced postpartum haemorrhage. The scientific and clinical discussion held in a forum, comprising experienced gynaecologists of India, discussed their clinical experience, shared their views and opinions on the Dinoprostone vaginal insert’s role in labour induction, reaching consensus through evidence-based statements.

Clay-polymer hybrid hydrogels in the vanguard of technological innovations for bioremediation, metal biorecovery, and diverse applications.

Polymeric hydrogels are among the most studied materials due to their exceptional properties for many applications. In addition to organic and inorganic-based hydrogels, "hybrid hydrogels" have been gaining significant relevance in recent years due to their enhanced mechanical properties and a broader range of functionalities while maintaining good biocompatibility. In this sense, the addition of micro- and nanoscale clay particles seems promising for improving the physical, chemical, and biological properties of hydrogels. Nanoclays can contribute to the physical cross-linking of polymers, enhancing their mechanical strength and their swelling and biocompatibility properties. Nowadays, they are being investigated for their potential use in a wide range of applications, including medicine, industry, and environmental decontamination. The use of microorganisms for the decontamination of environments impacted by toxic compounds, known as bioremediation, represents one of the most promising approaches to address global pollution. The immobilization of microorganisms in polymeric hydrogel matrices is an attractive procedure that can offer several advantages, such as improving the preservation of cellular integrity, and facilitating cell separation, recovery, and transport. Cell immobilization also facilitates the biorecovery of critical materials from wastes within the framework of the circular economy. The present work aims to present an up-to-date overview on the different "hybrid hydrogels" used to date for bioremediation of toxic metals and recovery of critical materials, among other applications, highlighting possible drawbacks and gaps in research. This will provide the latest trends and advancements in the field and contribute to search for effective bioremediation strategies and critical materials recovery technologies.

Re-designing nano-silver technology exploiting one-pot hydroxyethyl cellulose-driven green synthesis.

Re-designing existing nano-silver technologies to optimize efficacy and sustainability has a tangible impact on preventing infections and limiting the spread of pathogenic microorganisms. Advancements in manufacturing processes could lead to more cost-effective and scalable production methods, making nano-silver-based antimicrobial products more accessible in various applications, such as medical devices, textiles, and water purification systems. In this paper, we present a new, versatile, and eco-friendly one-pot process for preparing silver nanoparticles (AgNPs) at room temperature by using a quaternary ammonium salt of hydroxyethyl cellulose (HEC), a green ingredient, acting as a capping and reducing agent. The resulting nano-hybrid phase, AgHEC, consists of AgNPs embedded into a hydrogel matrix with a tunable viscosity depending on the conversion grade, from ions to nanoparticles, and on the pH. To investigate the synthesis kinetics, we monitored the reaction progress within the first 24h by analyzing the obtained NPs in terms of particle size (dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM)), Z-potential (ELS), surface plasmon resonance (UV-VIS), crystallographic phase (XRD), viscosity, and reaction yield (inductively coupled plasma-optical emission spectrometry (ICP-OES)). To explore the design space associated with AgHEC synthesis, we prepared a set of sample variants by changing two independent key parameters that affect nucleation and growth steps, thereby impacting the physicochemical properties and the investigated antimicrobial activity. One of the identified design alternatives pointed out an improved antimicrobial activity in the suspension, which was confirmed after application as a coating on nonwoven cellulose fabrics. This enhancement was attributed to a lower particle size distribution and a positive synergistic effect with the HEC matrix.

Soybean protein-reinforced highly extensible and self-adhesive hydrogels with ultra-sensitive strain sensing for flexible electronic devices

There is a growing interest in utilizing sustainable and renewable biomass resources to construct high-performance hydrogels for flexible electronics. In this study, soybean protein isolate (SPI) with abundant functional groups was introduced into the hydrogel matrix, while the connection between SPI, MXene and the polymer network was strengthened by hydrogen bonding. The sensible strategy overcame the problems of easy oxidation, agglomeration and weak interactions that existed in the binding of conductive filler MXene nanosheets with polymer chains. The prepared composite hydrogel exhibited integrated properties of high stretchability (>800 %), excellent self-adhesive property, plasticity, injectability, cyclic stability and durability in extreme environments (-20–60°C). Noteworthily, this hydrogel demonstrated high sensitivity and stable electrical resistance response to minor changes in tension, compression, bending, and temperature. In addition, this hydrogel exhibited excellent UV isolation and perspiration properties, making it ideal for practical applications of flexible devices in sports environments. The preparation of green, multipurpose, flexible electronics and human motion monitoring devices is made easier by the practical approach in this study.

Multi-deformable interpenetrating network thermosensitive hydrogel fluorescent device for real-time and visual detection of nitrite

Functionalized thermosensitive hydrogel materials exhibit excellent properties for the fabrication of sensing devices that enable real-time visual detection of food safety duo to their good plasticity and powerful loading capacity. Here, a ratiometric fluorescent device based on an interpenetrating network (IPN) thermosensitive hydrogel was designed to embed functionalized Au nanoclusters (Au NCs) and Blue Carbon dots (BCDs) composites in a multi-network structure to build a sensitive hazardous material nitrite (NO2-) chemsensor. The hydrogel was utilized poloxamer 407 (P407), lignin and cellulose to form stable IPN structure, which resulted in complementation and synergy, thereby strengthening its porous network structure. The combination of fluorescent nanoprobes with the porous network structure has the potential to enhance stable fluorescence signals and improve sensing sensitivity. Moreover, the thermosensitive liquid-solid transition characteristics of the hydrogel facilitate its preparation into diverse sensing devices following curing at room temperature. The hydrogel device, when combined with a smartphone system, converted image information into data information, thereby enabling the accurate quantification of NO2- with a detection limit of 9.38 nM in 2 s. The designed multi-functional hydrogel device is capable of real-time differentiation of NO2- dosage with the naked eye, offering a high-contrast, rapid-response sensing methodology for visual assessment of food freshness. This research contributes to the expansion of hydrogel materials applications and the detection of hazardous materials in food safety.

Hybrid biomaterial hydrogel loading iRGD&PS double modified lipid nanoparticles ameliorates diabetic wound healing through promoting efferocytosis and glycolysis-related macrophage reprogramming

Efferocytosis is a critical process whereby macrophages residing in the wound area play a key role in the efficient clearing and degradation of apoptotic neutrophils. This process is followed by a phenotypic transition toward an anti-inflammatory state, essential for inflammation resolution and tissue repair. The cystine/glutamate antiporter SLC7A11 has recently been identified as an inhibitor of efferocytosis, and its blockade has been found to enhance wound healing. In this study, we demonstrated that tiliroside, a plant-derived glycoside containing flavones, binds directly to SLC7A11 and pyruvate kinase isozyme M2 (PKM2). This was established by molecular docking predictions and activity-based protein profiling (ABPP). Cytological experiments revealed that tiliroside promoted the process of efferocytosis and led to glycolysis-related macrophage reprogramming. To facilitate targeted drug delivery to macrophages at diabetic wound sites, we designed a novel hybrid biomaterial. This hybrid biomaterial, prepared as Gel@Til iRGD&PS@PLGA NPs is manufactured by loading tiliroside (Til)-conjugated iRGD&PS double modified lipid nanoparticles (iRGD&PS@PLGA NPs) into a pH-responsive hydrogel matrix. The administration of Gel@Til iRGD&PS@PLGA NPs in diabetic cutaneous wound models has been shown to significantly promote tissue regeneration through the promotion of efferocytosis and glycolysis-related macrophage reprogramming. Therefore, this study introduces a novel approach to diabetic wound management by leveraging the promotion of efferocytosis.

Novel antimicrobial polysaccharide hydrogel with fertilizer slow-release function for promoting Sesamum indicum L. seeds germination

The problem of seed germination is one of the important scientific and technological issues facing the field of agroforestry cultivation, and the germination process requires both sufficient water and certain nutrients. The high solubility of fertilizers and pesticides makes their utilization inefficient, while water resources are costly in difficult standing environments. This article innovatively provides the preparation of hydrogels with slow-release function by using cellulose and chitosan as substrates, which have high water retention capacity and long-lasting fertilizer release (CCH/PVA/NCC/NPK). In this study, cellulose chitosan hydrogel (CCH) with 50 wt% of chitosan, 1 wt% of polyvinyl alcohol solution (PVA), 0.5 wt% of nanocellulose solution (NCC), and 2.5 wt% of nitrogen, phosphorus, and potassium (NPK) solution were used in optimized conditions to successfully prepare hydrogel materials with swelling as high as 79 g g−1 of CCH/PVA/NCC/NPK. Under neutral conditions, CCH/PVA/NCC/NPK has the slowest water release rate and the strongest water retention capacity, and it can greatly reduce the amount of fertilizers and the consumption of water resources, and it has a wide range of applications and prospects for development.

Preparation and characterization of structural and antifouling properties of chitosan/polyethylene oxide membranes

It aims to prepare the chitosan (CS) and polyethylene oxide (PEO) hydrogel membranes with different CS/PEO blend ratios (100:0, 95:5, 90:10, 80:20 and 70:30) via solvent casting. The physicochemical properties of these membranes were investigated using various characterization techniques: Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray (EDX), contact angle, and tensile testing. The interaction of PEO and chitosan was investigated by DSC in terms of freezing bound, freezing free, and non-freezing PEO fraction. The cross-sectional surface morphology of membranes displayed a smoother surface with increasing PEO content up to 20 %, beyond which nonhomogeneity on the surface was visible. The antifouling behavior of membranes was investigated by bacterial adherence study, which showed an enhanced antifouling nature of membranes with the increase in the PEO content. The peeling strength of the membranes was measured using a 90° angle peeling test, and it was found that 20 % and more PEO content promotes easy removal from the gelatin slab. In addition to this, live/ dead assay of the CS was performed to visualize the presence of live and dead bacteria on the surface. The CS/PEO blend with 20 % PEO content has properties makes it suitable for use as a protective layer on wound dressings to prevent bacterial growth. It's use in wound dressings has the potential to reduce the pain during the time of dressing removal and improve patient outcomes. The present investigation leads to the development of a CS hydrogel matrix which exhibits very interesting interaction with the PEO moiety along with its innovative feature of antifouling and antimicrobial nature.

Kombucha–Chlorella–Proteinoid Biosynthetic Classifiers of Audio Signals

ABSTRACTThis paper describes the development of a bioinspired composite material capable of audio classification applications. Hydrogel matrices produced by microorganisms combined with synthetic biology elements, allow for the development of adaptable bioelectronics that connect biology and technology in a customized way. In this study, a composite population of kombucha, chlorella, and proteinoids (thermal proteins) is utilized to respond to acoustic signals converted to electrical waveforms. The kombucha zoogleal mats, which are made and populated by over 60 species of yeasts and bacteria, offer a matrix at the micro level that is connected to the photosynthetic microalgae chlorella. Proteinoids formed through thermal condensation exhibit unique patterns of signaling kinetics. This living material has the ability to be electrically stimulated and can process signals in a way feasible for sensory applications. Using English alphabet audio inputs, a systematic analysis demonstrates the capability to differentiate audio waveforms based solely on biological composite responses. The use of spectral analysis allows for the identification of specific spike timing patterns that encode unique characteristics of individual letters. Moreover, network disturbances result in specific changes in output, so validating the ability to adjust waveform classification. The study demonstrates that kombucha–chlorella–proteinoid composites provide a durable and versatile bioelectronic platform for immediate auditory processing. The work represents progress toward the development of bioelectronic systems that can be customized based on the principles of biological sensory processing, cognition, and adaptation.

Hydrogel microspheres for stem cell recruitment and induction of directed differentiation in osteoarthritis therapy

The utilization of stem cell biotechnology for osteoarthritis (OA) treatment is hindered by high operational costs, difficulties in maintaining stem cell viability, and limited efficacy of unguided stem cell differentiation. Magnesium ions (Mg2+), crucial for tissue regeneration and repair, hold significant potential in OA treatment. However, further investigation is required to elucidate the precise mechanisms of Mg2+ in OA treatment. Here, we investigated the optimal concentration of Mg2+ to induce directed differentiation of stem cells and synthesized bioactive hydrogel microspheres (MDGM-Ps) capable of precisely releasing this concentration using microfluidic technology. Synthesized via polymerization of dopamine methacrylamide (DMA) and methacrylated gelatin (GelMA), these microspheres could chelate Mg2+ and incorporate platelet-derived growth factor-BB into the hydrogel matrix for sustained release. In vitro, MDGM-Ps showed excellent biocompatibility and promoted stem cell recruitment. Importantly, Mg2+ released from MDGM-Ps could guide stem cell differentiation through the PI3K-AKT pathway. Moreover, in vivo experiments suggested that MDGM-Ps could maintain the cartilage matrix and mitigate the progression of OA. In summary, MDGM-Ps not only harnessed the advantages of stem cell therapy, but also expanded the therapeutic applications of metal ions, thereby presenting a promising candidate for OA therapy.

Highly Conductive and Stretchable Hydrogel Nanocomposite Using Whiskered Gold Nanosheets for Soft Bioelectronics.

The low electrical conductivity of conductive hydrogels limits their applications as soft conductors in bioelectronics. This low conductivity originates from the high water content of hydrogels, which impedes facile carrier transport between conductive fillers. This study presents a highly conductive and stretchable hydrogel nanocomposite comprising whiskered gold nanosheets. A dry network of whiskered gold nanosheets is fabricated and then incorporated into the wet hydrogel matrices. The whiskered gold nanosheets preserve their tight interconnection in hydrogels despite the high water content, providing a high-quality percolation network even under stretched states. Regardless of the type of hydrogel matrix, the gold-hydrogel nanocomposites exhibit a conductivity of ≈520Scm-1 and a stretchability of ≈300% without requiring a dehydration process. The conductivity reaches a maximum of ≈3304Scm-1 when the density of the dry gold network is controlled. A gold-adhesive hydrogel nanocomposite, which can achieve conformal adhesion to moving organ surfaces, is fabricated for bioelectronics demonstrations. The adhesive hydrogel electrode outperforms elastomer-based electrodes in in vivo epicardial electrogram recording, epicardial pacing, and sciatic nerve stimulation.

Engineering PDA@CNTs-Enhanced sulfobetaine methacrylate hydrogels for superior flexible sensor applications

Conductive hydrogels have attracted significant attention as versatile materials for flexible sensors, with potential implementation in wearable technologies, electronic skins, and health diagnostics. However, traditional hydrogel models are frequently limited by their inadequate mechanical strength, poor conductivity, weak adhesion, and low durability, which pose significant barriers to their further application in flexible sensors. In this work, we prepared composite multifunctional hydrogels as flexible sensors, which were synthesized from sulfobetaine methacrylate SBMA) and acrylamide (AM), infused with dodecyl quaternary ammonium salt (Q12), and incorporated with poly(dopamine)-functionalized carbon nanotubes (PDA@CNTs). The PDA modification enhances the compatibility of CNTs with the hydrogel matrix. The incorporation of PDA@CNTs into the hydrogel matrix, along with the establishment of multiple dynamic bonds—such as ionic bonds, hydrogen bonds, cation-π interactions, and π-π stacking between polymer chains and PDA moieties—significantly enhances its tensile strength (53.79 kPa), toughness (134.77 kJ/m3), adhesive capabilities (29.84 kPa to paper), and electrical conductivity (0.2 S/m). Moreover, the composite hydrogel reveals a remarkable mechanical strain response, coupled with impressive stability and durability over prolonged periods. It efficiently differentiates between mild elongations (10%–40 %) and substantial elongations (50%–300 %), thereby showcasing its capability for real-time biomechanical motion monitoring. Additionally, the composite hydrogel displays remarkable photothermal antibacterial efficacy upon exposure to near-infrared (NIR) radiation, along with outstanding biocompatibility under standard conditions, thereby confirming its suitability for safe and long-term biological interactions. The exceptional functionality of these composite hydrogels renders them highly conducive to diverse applications in the realm of wearable sensor technologies.

Suppression the glucose-induced ferroptosis in endothelial cells by 4OI-loading exosomes hydrogel for the treatment of diabetic foot ulcer

The prevalence of diabetic foot ulcer in individuals with diabetes is approximately 15%, and it is frequently accompanied by vascular dysfunction and infection. The management challenges make it the primary cause for amputation; however, the underlying mechanisms remain poorly understood, thereby impeding the advancement of novel wound dressings and medication. Herein, single-cell sequencing analysis revealed that ferroptosis induced by high glucose levels in vascular endothelial cells (VECs) represents a significant molecular pathological feature in diabetic foot ulcer (DFU) tissue. Furthermore, 4-Octyl itaconate (4OI) exhibited a pronounced protective effect against VECs injury induced by high glucose (HG), and its underlying molecular mechanisms involve the mitigation of HG-induced reactive oxygen species (ROS) injury and ferroptosis in VECs through the regulation Keap1/Nrf2/GPX4. For enhanced application, incubation at 37℃ was used to load 4OI into exosomes, which were subsequently encapsulated within an Alg-DA/GelMA-based hydrogel matrix. Remarkably, the utilization of 4OI-Exo-Gel not only expedited wound healing but also significantly improved the overall quality of healing in DFU. In conclusion, these findings not only demonstrate, for the first time, the remarkable ability of 4OI to enhance diabetic wound healing by mitigating VECs ferroptosis induced by HG, but also provide evidence for the potential clinical translation of a 4OI-loaded exosomes hydrogel in diabetic wound therapy.

Advanced In-Situ functionalized conductive hydrogels with high mechanical strength for hypersensitive soft strain sensing applications

Conductive hydrogels are used in wearable electronics, soft robotics and artificial skin due to their flexibility, biocompatibility and multifunctionality. However, combining high mechanical strength, conductivity and sensitivity in these hydrogels remains a challenge. This paper proposes a novel in-situ conductive functionalization technology for hydrogels with high mechanical strength, achieving high conductivity (3223.727 S·m−1) and low resistance (0.92 Ω) without sacrificing mechanical properties. Comprehensive experiments reveal the mechanisms and optimal parameters for conductive functionalization. AgNO3 and ascorbic acid (VC) concentrations influence the distribution, reaction rate and aggregation of Ag particles on hydrogel surfaces. Sodium carboxymethylcellulose (CMC) enhances mechanical strength and Ag+ adsorption capacity. Optimal parameters are 1.00 M AgNO3 and 0.08 M VC. An in-situ reduction reaction of silver particles establishes strong interfacial bonding between the silver layer and hydrogel matrix, forming the basis for strain sensing. The hypersensitized sensing mechanism, involving the appearance and recovery of microcracks on the silver layer via the tunneling effect, enables high sensitivity (gauge factor = 36.65). The conductive hydrogels can monitor human physiological signals, tiny strain signals from water droplets (0.01 g) and airflow, with an average response time of 12.7 ms. The developed conductive hydrogels meet the technical requirements for combining high mechanical strength and sensitivity, offering an efficient new approach for conductive hydrogel-based soft strain sensors.

Single-Walled Carbon Nanotubes As Fluorescent Probes for Supramolecular Self-Assembly Complexes

Semiconducting single-walled carbon nanotubes (SWCNTs) are distinguished by their fluorescence in the near-infrared range, which overlaps with the transparency window of biological samples, and they do not photobleach or blink. Utilizing their unique optical properties, SWCNTs can be rendered optical probes for the characterization and analysis of bio-inspired peptide-based hydrogels. Peptide hydrogels, formed through the supramolecular self-assembly of conjugated amino acids, provide versatile three-dimensional scaffolds for applications in cell culture, tissue engineering, and regenerative medicine. The inherent properties of these amino acids or peptides, notably their limited solubility in water, drive them to self-assemble into elongated fibrillary nanostructures, ultimately creating self-supporting hydrogel matrices. We integrate near-infrared fluorescent SWCNTs into these peptide hydrogels as dynamic fluorescent probes, offering real-time insights into the morphological and structural evolution of the hydrogels. This approach not only enhances our understanding of the self-assembly mechanisms at play but also opens new avenues in supramolecular science. The integration of SWCNTs into the supramolecular structures showcases their potential as a powerful tool for long-term, non-invasive monitoring, with immense promise for numerous biomedical applications.

Bioinspired Self-Growing Layered Hydrogel Enabled by Catechol Chemistry-Mediated Interfacial Catalytic System.

Tissue-inspired layered structural hydrogel has attracted increasing attention in artificial muscle, wound healing, wearable electronics, and soft robots. Despite numerous efforts being devoted to developing various layered hydrogels, the rapid and efficient preparation of layered hydrogels remains challenging. Herein, inspired by the self-growth concept of living organisms, an interfacial catalytic self-growth strategy based on catechol chemistry-mediated self-catalytic system of preparing layered hydrogels is demonstrated. Typically, the tannic acid-metal ion (e.g., TA-Fe3+) complex embedded in the hydrogel substrate would catalytically trigger rapid solid-liquid interfacial polymerization to grow the hydrogel layer without bulk solution polymerization. The self-growth process can be finely controlled by changing the growth time, the molar ratio of Fe3+/TA, and so on. The strategy is applicable to prepare various layered hydrogels as well as complex layered hydrogel patterns, allowing the customization of the physicochemical properties of the hydrogel. In addition, the self-adhesive layered hydrogel was prepared and can be utilized as a wearable strain sensor to monitor physiological activities and human motions. The demonstrated interfacial catalytic self-growth strategy will provide a route to design and fabricate layered hydrogel materials.