Hydrogel Components Research Articles

A Hydrogel for Nitric Oxide Sensitization Chemotherapy Mediated by Tumor Microenvironment Changes in 3D Spheroids and Breast Tumor Models.

Nitric oxide (NO) is a low-toxicity and high-efficiency anticancer treatment that can augment the cytotoxicity of doxorubicin (DOX) towards breast cancer cells, thereby exhibiting a favorable effect on chemotherapy sensitization. The study aimed to establish a hydrogel that sensitizes chemotherapy by inducing local inflammatory stimulation to change the tumor microenvironment and promote NO production. The purpose of the study was to examine the anti-tumor effect in vivo and in vitro. The functional properties of the composite hydrogels were tested by UV spectrophotometry and NO detection kit. CCK8, DCFH-DA fluorescent probe, Calcein-AM/PI detection kit, and confocal detection methods were used for the cytocompatibility and cytotoxicity of the composite hydrogels. The subcutaneous tumor volume, weight, and tumor inhibition rate of 4T1 breast cancer cells were evaluated for pharmacodynamic study in vivo. Each component of hydrogel has good biocompatibility. The combination of gas therapy and chemotherapy can significantly enhance the effect of inhibiting tumor cell growth. The tumor growth of tumor- bearing mice in the hydrogel administration group was slow, and the tumor inhibition rate was 85.10%. The body weight grew steadily, and no significant pathological changes were observed in the H&E staining of major organs. A composite hydrogel with alginate as the carrier was successfully established, which was based on improving the tumor microenvironment to trigger gas therapy combined with chemotherapy for tumor treatment.

A flexible wearable sensor based on the multiple interaction and synergistic effect of the hydrogel components with anti-freezing, low swelling for human motion detection and underwater communication.

To meet the increasing demand for wearable sensor in special environment such as low temperature or underwater, a multifunctional ionic conducting hydrogel (Gel/PSAA-Al3+ hydrogel) with anti-freezing and low swelling for human motion detection and underwater communication was prepared using gelatin (Gel), [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA), acrylamide (AAm), acrylic acid (AAc), and AlCl3. Due to reversible hydrogen bonding, electrostatic interactions and metal coordination crosslinking between the polymer networks, the resulting Gel/PSAA-Al3+ hydrogels present low swelling property in water and exhibit large tensile properties (~1050 %), high tensile strength (~250 kPa) and excellent fatigue resistance. In addition, the hydration capacity of SBMA and AlCl3 endows the Gel/PSAA-Al3+ hydrogel fantastic anti-freezing (-31.58 °C) and water retention properties. Moreover, the electrostatic interaction between SBMA and AlCl3 due to the ion hopping mechanism endows the hydrogel with excellent ionic conductivity (6.38 mS/cm). The Gel/PSAA-Al3+ hydrogel sensors present good biocompatibility and provide a wide operating range (0 %-1050 %), fast response time (229 ms) and recovery time (248 ms), high sensitivity (GF = 1.61) and excellent stability for detecting large and small body movements. The Gel/PSAA-Al3+ hydrogel shows potential applications as a wearable sensor for communication at low temperature or underwater.

Photocrosslinking of hyaluronic acid-based hydrogels through biotissue barriers.

Photocrosslinkable hydrogels based on hyaluronic acid are promising biomaterials high in demand in tissue engineering. Typically, hydrogels are photocured under the action of UV or blue light strongly absorbed by biotissues, which limits prototyping under living organism conditions. To overcome this limitation, we propose the derivatives of well-known photosensitizers, namely chlorin p6, chlorin e6 and phthalocyanine, as those for radical polymerization in the transparency window of biotissues. Taking into account the efficiency of radical generation and dark and light cell toxicity, we evaluated water miscible pyridine phthalocyanine as a promising initiator for the intravital hydrogel photoprinting of hyaluronic acid glycidyl methacrylate (HAGM) under irradiation near 670 nm. Coinitiators (dithiothreitol or 2-mercaptoethanol) reduce the irradiation dose required for HAGM crosslinking from ∼405 J cm-2 to 80 J cm-2. Patterning by direct laser writing using a scanning 675 nm laser beam was performed to demonstrate the formation of complex shape structures. Young's moduli typical of soft tissue (∼270-460 kPa) were achieved for crosslinked hydrogels. The viability of human keratinocytes HaCaT cells within the photocrosslinking process was shown. To demonstrate scaffolding across the biotissue barrier, the subcutaneously injected photocomposition was crosslinked in BALB/c mice. The safety of the irradiation dose of 660-675 nm light (100 mW cm-2, 15 min) and the non-toxicity of the hydrogel components were confirmed by histomorphologic analysis. The intravitally photocrosslinked scaffolds maintained their shape and size for at least one month, accompanied by slow biodegradation. We conclude that the proposed technology provides a lucrative opportunity for minimally invasive scaffold formation through biotissue barriers.

Hydrogel-Assisted Robust Supraparticles Evolved from Droplet Evaporation.

Supraparticles, formed through the self-assembly of nanoparticles, are promising contenders in catalysis, sensing, and drug delivery due to their exceptional specific surface area and porosity. However, their mechanical resilience, especially in dimensions spanning micrometers and beyond, is challenged by the inherently weak interactions among their constituent building blocks, significantly constraining their broad applicability. Here, we have exploited a robust supraparticle fabrication strategy by integrating hydrogel components into the assembly system and evaporating on the superamphiphobic surface. The resultant SiO2/SA (sodium alginate) supraparticles, achieved by evaporating a 15% volume fraction dispersion of SiO2 nanoparticles containing 18.46 mg/mL of sodium alginate and subsequently cross-linking with Ca2+, demonstrate mechanical robustness with a fracture force of 6.04 N, representing a mechanical strength enhancement of 60 times higher than that prior to the incorporation of the hydrogel component. The supraparticles maintain their original morphology after 30 min of ultrasonic treatment (200 W), demonstrating mechanical stability. This method exhibits generalizability, enabling the customization of supraparticles with various building blocks and hydrogel backbone materials. Based on such a methodology, we have synthesized enzyme-carrying supraparticles, further expanding the potential applications in intricate cascade reactions. The encapsulated glucose oxidase and horseradish peroxidase maintained their inherent reactivity, and such hydrogel-assisted robust supraparticles exhibited exceptional performance in accurate glucose assays, indicating great practical application in biocatalysis.

Studying the Effect of Reducing Agents on the Properties of Gold Nanoparticles and Their Integration into Hyaluronic Acid Hydrogels

Gold nanoparticles (Au NPs) are a promising target for research due to their small size and the resulting plasmonic properties, which depend, among other things, on the chosen reducer. This is important because removing excess substrate from the reaction mixture is problematic. However, Au NPs are an excellent component of various materials, enriching them with their unique features. One example is hydrogels, which provide a good, easily modifiable base for multiple applications such as cosmetics. For this purpose, various compounds, including hyaluronic acid (HA) and its derivatives, are distinguished by their high water-binding capacity and many characteristics resulting from their natural origin in organisms, including biocompatibility, biodegradability, and tissue regeneration. In this work Au NPs were synthesized using a green chemistry method, either by using onion extract as a reductant or chemically reducing them with sodium citrate. A complete characterization of the nanoparticles was carried out using the following methods: Fourier-Transform Infrared Spectroscopy (FT-IR), Electrophoretic (ELS), and Dynamic Light Scattering (DLS) as well as Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). Their antioxidant activity was also tested using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The results showed that the synthesized nanoparticles enrich the hydrogels with antioxidant properties and new surface properties (depending on the reducing agent, they can be more hydrophilic or hydrophobic). Preliminary observations indicated low cytotoxicity of the nanomaterials in both liquid form and as a hydrogel component, as well as their lack of penetration through pig skin. The cosmetic properties of hydrogel masks were also confirmed, such as increasing skin hydration.

Human Tendon-on-a-Chip for Modeling the Myofibroblast Microenvironment in Peritendinous Fibrosis.

Understanding the myofibroblast microenvironment is critical to developing therapies for fibrotic diseases. Here the development of a novel human tendon-on-a-chip (hToC) is reported to model this crosstalk in peritendinous adhesions, which currently lacks biological therapies. The hToC facilitates cellular and paracrine interactions between a vascular component, which contains endothelial cells and monocytes, and a tissue hydrogel component that houses tendon cells and macrophages. It is found that the hToC replicates some aspects of in vivo inflammatory and fibrotic phenotypes in preclinical and clinical samples, including activated mTOR signaling, vascular inflammation, tissue contraction induced by myofibroblast activation, inflammatory cytokines secretion, and transendothelial migration of monocytes to the tissue hydrogel. Transcriptional analysis demonstrates significant overlap in enriched pathways in the hToC with human tenolysis samples, including the activation of mTOR signaling. Rapamycin suppresses the vascular inflammation and fibrotic phenotype in the hToC, which provides proof-of-concept of its utility as an in vitro tool for investigating multicellular crosstalk in fibrosis and testing therapeutics to mitigate it.

Gluing osteochondral fragments: development of a novel strategy for dual adhesive application in a preclinical model

This study proposes a novel dual adhesive approach for fixing osteochondral fractures, aiming to address the limitations of current fixation methods by incorporating both a bone adhesive (phosphoserine modified calcium phosphate cement PM-CPC) and a cartilage adhesive (methacrylated phosphoserine-containing gelatin MePGa hydrogel). The feasibility and efficacy of this approach were investigated using an ex vivo bovine knee model. Results indicate successful gluing of osteochondral cylinders with both adhesives, with no significant difference in adhesion strength between the groups (adhesion strength mean of 1211.6 kPa, SD 602.4 kPa, and mean of 1299.6 kPa, SD 850.9 kPa for groups 1 and 2 respectively). Importantly, the inclusion of the hydrogel component in the dual adhesive system aims to enhance cartilage repair potential, complementing the mechanical support provided by the bone adhesive. Each adhesive offers distinctive benefits: PM-CPC for mechanical support and bone repair, and MePGa hydrogel for cartilage repair. The study demonstrates the potential of the dual adhesive strategy for osteochondral repair, though further refinement and in vivo validation are needed.

Optimization of the Oxygen Permeability of Non-Silicone Hydrogel Contact Lenses Through Crosslinking Modifications.

The main weakness of non-silicone hydrogel contact lenses is their low oxygen permeability (Dk). Hence, we have tried to optimize their Dk using various concentrations and lengths of the poly (ethylene glycol) dimethacrylate crosslinker in a mixture of N,N-Dimethylacrylamide and Cyclohexyl methacrylate monomers. After synthesizing the different contact lenses, we evaluated their chemical, optical, and mechanical properties. The resultant non-silicone hydrogel contact lenses presented similar high water contents (75.69-80.60%) and adequate optical (e.g., a transmittance ranging from 85.91% to 99.91% and a refractive index between 1.3630 and 1.3740) and elongation at break (178.95-356.05%) characteristics for clinical applications. Conversely, they presented high contact angles (81.00-100.00°) and a low Young's modulus (0.066-0.167 MPa). Regarding the impact of the crosslinking modifications, the water content, contact angle, refractive index, transmittance, and Young's modulus of the synthesized lenses were slightly affected by crosslinker conditions. In contrast, the elongation at break (178.95-356.05%) and, more importantly, the oxygen permeability, which reached values of up to 73.90 Fatt units, were considerably impacted by the crosslinker conditions. To our knowledge, this study demonstrates for the first time that, in addition to water, other usual hydrogel components, like crosslinkers, can modulate the Dk of non-silicone contact lenses. It also provides a simple and scalable method to fabricate more permeable non-silicone lenses.

Ion-Mediated Cross-Linking of Hyaluronic Acid into Hydrogels without Chemical Modification.

Hyaluronic acid (HA) is a biomedically relevant polymer widely explored as a component of hydrogels. The prevailing approaches for cross-linking HA into hydrogels require chemically modifying the polymer, which can increase processing steps and complicate biocompatibility. Herein, we demonstrate an alternative approach to cross-link HA that eliminates the need for chemical modifications by leveraging the interactions between metal cations and the negatively charged, ionizable functional groups on HA. We demonstrate that HA can be cross-linked with the bivalent metal cations Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), and notably Mg(II). Using Mg(II) as a model, we show that ion-HA hydrogel rheological properties can be tuned by altering the HA molecular weight and concentrations of ions, NaOH, and HA. Mg(II)-HA hydrogels showed the potential for self-healing and stimulus response. Our findings lay the groundwork for developing a new class of HA-based hydrogels for use in biomedical applications and beyond.

Carbon Dots Infused 3D Printed Cephalopod Mimetic Bactericidal and Antioxidant Hydrogel for Uniaxial Mechano-Fluorescent Tactile Sensor.

Cephalopods use stretchy skin and dynamic color-tuning organs for visual communication and camouflage. Inspired by these natural mechanisms, a fluorescent biomaterial for deformation-induced illumination and optical communication is proposed. This is the first report of 3D printed soft biomaterials infused with carbon dots hydrothermally derived from chitosan and benzalkonium chloride. These biomaterials exhibit a comprehensive array of properties, including significant uniaxial stretching, near-instantaneous response to tactile stimuli and pH, UV resistance, antibacterial, antioxidant, noncytotoxicity, and highlighting their potential as mechano-optical materials for biomedical applications. The hydrogel's durability is evaluated by cyclic stretching, folding, rolling, and twisting tests to ensure its integrity and good signal-to-noise ratio. The diffusion mechanism is determined by water imbibition kinetics, network parameters, and time-dependent breathing. Overcoming the common limitations of short lifespans and complex manufacturing processes in existing soft hybrids, this work demonstrates a straightforward method to produce durable, energy-independent, mechano-optical hydrogel. Combined with investigations, molecular dynamic modeling is used to understand the interactions of hydrogel components.

Dynamic polysaccharide/platelet-rich plasma hydrogels with synergistic antibacterial activities for accelerating infected wound healing

Platelet-rich plasma (PRP) has been recognized as an effective therapy in regenerative medicine and surgery, which can reduce the risk of antibiotic abuse and promote the healing of infected wounds. Recent advances in PRP-based treatments have focused on the controlled release of growth factors in PRP with biocompatible hydrogels and antimicrobial promotion by introducing hydrogel components or antibiotics, while the inherent antimicrobial activity of PRP is mostly neglected or sacrificed. Here, we demonstrate the combination of an antimicrobial polysaccharide, carboxymethyl chitosan, and PRP to construct an antimicrobial hydrogel via dynamic bonding with oxidized chondroitin sulfate. Significant inhibitory effects against Staphylococcus aureus and Escherichia coli (95 % of inhibition rate) are achieved through the synergistic contributions of the polysaccharide and PRP. Additionally, the resulting hydrogel promotes the migration of NIH-3T3 fibroblasts and collagen deposition by approximately 1.7 and 1.8 times, respectively, thereby accelerating the healing process of infected wounds. This work may bring new perspectives for potent applications of PRP-based hydrogel dressings for antibiotic-free management of infected wounds.

Strategic Approaches in Generation of Robust Microphysiological 3D Musculoskeletal Tissue System

AbstractSkeletal muscle plays a vital role in maintaining the body's shape and regulating various physiological processes. Its function is influenced by a multitude of factors. Given the lack of uniformity in prior research regarding the size and placement of structural pillars within the chip, as well as the choice of cell‐laden hydrogel components with various densities of extracellular matrix, in different gelation times, and cell densities, a meticulous investigation is conducted to enhance the robustness of 3D in vitro musculoskeletal tissues. This study provides guidance on how to optimize the design parameters of skeletal muscle‐on‐a‐chip and hydrogel recipe by evaluating the impact of design elements and hydrogel fabrication conditions on tissue formation and musculoskeletal differentiation. This research reports the direct evidence of mechanical properties of hydrogels are critical in influencing cellular differentiation and tissue functionality through the process of mechanotransduction. The study highlights the importance of standardizing experimental conditions in 3D in vitro musculoskeletal research, and presents a validated framework as a foundation to aid in the development of functional musculoskeletal tissue for clinical and research applications, including disease modeling and regenerative therapies.

RhBMP-2-loaded hydroxyapatite/beta-tricalcium phosphate microsphere/hydrogel composite promotes bone regeneration in a novel rat femoral nonunion model.

Nonunion following fracture treatment remains a significant clinical challenge, adversely affecting the patient's quality of life and imposing a substantial economic burden. The emergence of bone morphogenetic protein 2 (BMP-2) for bone regeneration represents a promising avenue, albeit limited by side effects such as inflammatory reactions primarily due to suboptimal drug delivery systems. This study focuses on NOVOSIS putty (NP), a novel biomaterial designed for the sustained release of BMP-2, aiming to mitigate these limitations and enhance bone healing. This research aimed to evaluate the effectiveness of NP, a hydroxyapatite granules/β-tricalcium phosphate hydrogel composite (HA/β-TCP/hydrogel), as a BMP-2 carrier for promoting bone regeneration in a new rat nonunion model of long bone. Using Sprague Dawley rats, a 2-mm silicone disk was interposed at the femoral fracture site, and intramedullary fixation with K-wire was performed to create a nonunion with a 2-mm bone defect. After 3weeks, internal fixation with a plate, removal of the silicon disk, and refreshing the nonunion site were performed by implanting three different materials into the nonunion sites: allogenic iliac bone (IB), collagen sponge (CS) containing 10μg of BMP-2, or NP containing 10μg of BMP-2. Bone healing was evaluated weekly using micro-computed tomography (CT); ex vivo micro-Ct and histological evaluation were conducted at 6weeks. At 6weeks, NP demonstrated a significantly higher bone union rate (76.5%) compared with the CS group (35.3%, p = 0.037), and the IB group (6.3%, p < 0.0001). Bone mineral density (BMD) and bone volume/tissue volume (BV/TV) were also significantly higher in the NP group compared with the CS group (BMD, p < 0.0001; BV/TV, p = 0.031). Histological analysis showed the fracture gap in the NP group was filled with more trabecular bone and less fibrous tissue compared with the CS group. The study confirms NP is a highly effective BMP-2 carrier, significantly improving bone union rates and new bone formation in nonunion fractures. The sustained release of BMP-2 from the hydrogel component reduced inflammatory responses and enhanced bone regeneration. NP can be a promising alternative to collagen-based BMP-2 delivery systems.

Synergistic antibacterial and wound healing effects of chitosan nanofibers with ZnO nanoparticles and dual antibiotics

One concern that has been considered potentially fatal is bacterial infection. In addition to the development of biocompatible antibacterial dressings, the screening and combination of new antibiotics effective against antibiotic resistance are crucial. In this study, designing hemostasis electrospun composite nanofibers containing chitosan (CS), polyvinyl pyrrolidone (PVP) and Gelatin (G) as the major components of hydrogel and natural nanofibrillated sodium alginate (SA)/polyvinyl alcohol (PVA) and ZnO nanoparticles (ZnONPs) combination as the nanofiller ingredient, has been investigated which demonstrated significant potential for accelerating wound healing. The hydrogels were developed for the delivery of the amikacin and cefepime antibiotics, along with zinc oxide nanoparticles that were applied to an electrospun layer. Amikacin is a highly effective aminoglycoside antibiotic, particularly for hospital-acquired infections, but its use is limited due to its toxicity. By utilizing it in low concentrations in the form of nanofibers and combining it with cefepime, which exhibits synergistic effects, enhanced efficacy against bacterial pathogens is achieved while potentially minimizing cytotoxicity compared to individual antibiotics. This dressing demonstrated efficient drug release, flexibility, and good swelling properties, indicating its suitable mechanical properties for therapeutic applications. After applying the biocompatible hydrogel to wounds, a significant acceleration in wound closure was observed within 14 days compared to the control group. Furthermore, the notable antibiotic and anti-inflammatory properties underscore its effectiveness in wound healing, making it a promising candidate for medical applications.

Silk-enriched hydrogels with ROS-scavenging dendrimers for advanced wound care

This study explores the development of novel hydrogel composites for wound care, incorporating silk fibroin and reactive oxygen species (ROS)-scavenging dendrimers into a polyvinyl alcohol (PVA) matrix. Utilizing ionizing gamma radiation, we fabricated pristine PVA, silk-PVA (SPVA) binary, and dendrimer-silk-PVA (DSPVA) ternary hydrogel composites, with their composition confirmed via UV–visible absorption spectroscopy. Fourier-transform infrared (FTIR) and Raman spectroscopy analyses indicated complex interactions between the hydrogel components, enhancing their structural and biocompatible properties. Scanning electron microscopy (SEM) analysis revealed that dendrimer integration in DSPVA hydrogels significantly increased surface porosity, vital for tissue regeneration. The DSPVA hydrogels demonstrated effective ROS scavenging, reducing hydrogen peroxide (H2O2) concentrations by approximately 70 % within 24 h. In vivo wound healing studies in a diabetic mouse model showed enhanced wound closure in the DSPVA group, with a relative wound area reduction to 30 ± 4.3 % on day 10, compared to 56.5 ± 2.7 % in the control group. By the 16th day, the treated group exhibited near-complete wound contraction, markedly outperforming the control group. These findings underscore the potential of DSPVA hydrogels in diabetic wound management, combining silk fibroin's mechanical support, dendrimers' antioxidative properties, and PVA's structural benefits. Thus, DSPVA hydrogels are promising candidates for advanced wound care applications.

Regulating natural galactomannan into composite hydrogels for improved adhesion, anti-swelling capability and efficient dye pollution removal

Constructing bio-based composite hydrogel materials are receiving much interest, while regulating the interactions of the hydrogel components and integrating functions for multi-application meet various challenges. Herein, composite hydrogels were prepared by cross-linking of poly-acrylamide (PAM) and poly-N-[3-(Dimethylamino) propyl] acrylamide (PDMAPAA), assisted by natural galactomannan (GM) regulation. Even distribution and compatibility of GM in the three-dimensional materials were proved by a series of chemical and morphological characterizations, which favored the improvement of mechanical properties (~80 kPa) and flexibility. Besides, the hydrogels were well-connected with double networks of noncovalent intermolecular hydrogen bonding interactions and hydrophobic interactions, in addition to covalent-linked polymers. Due to great amount of inner hydrogen bond linkages, the hydrogels present satisfying anti-swelling capabilities (<15 %), exhibiting high potential for application in water treatment. Meanwhile, abundant surface functional groups provided possibilities to form interactive layer with the various substrates surface, exhibiting highly adhesive properties. Significant dyes adsorption capabilities were revealed on the hydrogels according to the electrostatic attraction with Congo red and hydrogen bond interactions with Brilliant green respectively. Thus, the proposed composite hydrogels integrated multi-functions due to the tuning the surface groups and cross-linking interactions, which provided deeper understanding on bio-based materials on fields of water treatment and environmental protection.

Architectural engineering of Cyborg Bacteria with intracellular hydrogel

Synthetic biology primarily uses genetic engineering to control living cells. In contrast, recent work has ushered in the architectural engineering of living cells through intracellular materials. Specifically, Cyborg Bacteria are created by incorporating synthetic PEG-based hydrogel inside cells. Cyborg Bacteria do not replicate but maintain essential cellular functions, including metabolism and protein synthesis. Thus far, Cyborg Bacteria have been engineered using one primary composition of intracellular hydrogel components. Here, we demonstrate the versatility of controlling the physical and biochemical aspects of Cyborg Bacteria using different structures of hydrogels. The intracellular cell-gel architecture is modulated using a different photoinitiator, PEG-diacrylate (PEG-DA) of different molecular weights, 4arm PEG-DA, and dsDNA-PEG. We show that the molecular weight of the PEG-DA affects the generation and metabolism of Cyborg Bacteria. In addition, we show that the hybrid dsDNA-PEG intracellular hydrogel controls protein expression levels of the Cyborg Bacteria through post-transcriptional regulation and polymerase sequestration. Our work creates a new frontier of modulating intracellular gel components to control Cyborg Bacteria function and architecture.

Light‐Encoding of a Supramolecular Hydrogel for Assembly‐Free Soft Machines Capable of Sequential and Multistage Shape‐Morphing

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

Nanozyme microspheres with structural color-coding labels for synergistic therapy of psoriasis

Psoriasis is an immune system-mediated skin disease identified by the appearance of erythematous as a central symptom. As a recurrent and chronic inflammatory disease, psoriasis is influenced by both genetic and environmental factors and is known to be with no effective cure. Considering a multifaceted etiology of psoriasis, synergistic therapy exhibits great benefits over monotherapy, which becomes common for the treatment of various diseases. Herein, we present the nanozyme microspheres with structural color-coding labels for synergistic therapy of psoriasis. In particular, microsphere hydrogel is fabricated by the edible hydroxypropyl cellulose (HPC), which can generate a photonic liquid crystalline mesophase under lyotropic conditions in solution. Through adjustment of hydrogel components, microspheres endow with different functions, including moisturizing (paraffin), cfDNA scavenging (chitosan), and anti-inflammation (cerium oxide nanozyme). To improve patient convenience, hydrogel drops with different properties are tailored with different vivid structural colors by exploiting the lyotropic behavior of HPC. Of particular note, both in vitro and in vivo experiments have demonstrated the significant therapeutic effects of the encoded structural color microspheres. Green moisturizing microspheres facilitate to relieve dry, flaky skin patches; blue cfDNA scavenging and red anti-inflammatory microspheres significantly reduce skin inflammation. More importantly, combination therapy with encoded microspheres exerted the synergistic effects, including the increased body weight, thicker epidermal layer, and reduced immune activation. Overall, this synergistic treatment offers a promising platform for personalized management of psoriasis and various inflammatory skin diseases.

Nanolignin-Facilitated Robust Hydrogels.

Recently, certain challenges and accompanying drawbacks have emerged in the preparation of high-strength and tough polymer hydrogels. Insights from wood science highlight the role of the intertwined molecular structure of lignin and crystalline cellulose in contributing to wood's strength. Herein, we immersed prestretched poly(vinyl alcohol) (PVA) polymer hydrogels into a solution of nanosized lignosulfonate sodium (LS), a water-soluble anionic polyelectrolyte, to creatively reconstruct this similar structure at the molecular scale in hydrogels. The nanosized LS effectively fixed and bundled the prestretched PVA polymers while inducing the formation of dense crystalline domains within the polymer matrix. Consequently, the interwoven structure of crystalline PVA and LS conferred good strength to the composite hydrogels, exhibiting a tensile strength of up to ∼23 MPa, a fracture strain of ∼350%, Young's modulus of ∼17 MPa, toughness of ∼47 MJ/m3, and fracture energy of ∼42 kJ/m2. This hydrogel far outperformed previous hydrogels composed directly of lignin and PVA (tensile strength <1.5 MPa). Additionally, the composite hydrogels demonstrated excellent antifreezing properties (<-80 °C). Notably, the LS-assisted reconstruction technology offers opportunities for the secondary fixation of PVA hydrogel shapes and high-strength welding of hydrogel components. This work introduces an approach for the high-value utilization of LS, a green byproduct of pulp production. LS's profound biomimetic strategy will be applied in multifunctional hydrogel fields.