Glucose-Activated Nanoconfinement Supramolecular Cascade Reaction in Situ for Diabetic Wound Healing

New Advances in Periodontal Functional Materials Based on Antibacterial, Anti-Inflammatory, and Tissue Regeneration Strategies

With the global population aging, awareness of oral health is rising. Periodontitis, a widespread bacterial infectious disease, is gaining attention. Current novel biomaterials address key clinical issues like bacterial infection, gum inflammation, tooth loosening, and loss, focusing on antibacterial, anti-inflammatory, and tissue regeneration properties. However, strategies that integrate the advantages of these biomaterials to achieve synergistic therapeutic effects by clearing oral biofilms, inhibiting inflammation activation, and restoring periodontal soft and hard tissue functions remain very limited. Recent studies highlight the link between periodontitis and systemic diseases, underscoring the complexity of the periodontal disease. There is an urgent need to find comprehensive treatment plans that address clinical requirements. Whether by integrating new biomaterials to enhance existing periodontal treatments or by developing novel approaches to replace traditional therapies, these efforts will drive advancements in periodontitis treatment. Therefore, this review compares novel biomaterials with traditional treatments. It highlights the design concepts and mechanisms of these functional materials, focusing on their antibacterial, anti-inflammatory, and tissue regeneration properties, and discusses the importance of developing comprehensive treatment strategies. This review aims to provide guidance for emerging periodontitis research and to promote the development of precise and efficient treatment strategies.

Amyloid-Templated Ceria Nanozyme Reinforced Microneedle for Diabetic Wound Treatments

Amyloid fibrils have emerged as excellent templates and building blocks for the development of ordered functional materials with considerable potential in biomedical applications. Here, lysozyme amyloid fibrils (Lys-AFs) are employed as templates for the in situ synthesis of ceria nanozymes (Lys-AFs-Ceria) with ultrafine dimensions, an optimized Ce3+/Ce4+ ratio, and uniform distribution on the fibril surface, addressing the challenges of low catalytic efficiency and high susceptibility to aggregation typical of traditional methods. As a proof of concept, it is further applied Lys-AFs-Ceria to develop hydrogel/microneedle for treating bacteria-infected diabetic wounds via non-covalent interactions between polyphenols and amyloid fibrils incorporating glucose oxidase (GOX). The hydrogel/microneedle facilitates superoxide dismutase and catalase cascade catalysis by Lys-AFs-Ceria, and integrates GOX-mediated glucose consumption, synergistically achieving glucose reduction, reactive oxygen species elimination, and hypoxia alleviation in the diabetic wound infection microenvironment. In addition to antibacterial properties and tissue regeneration promotion of Lys-AFs scaffold, Lys-AFs-Ceria regulates macrophages polarization toward an anti-inflammatory M2 state. Collectively, these attributes contribute to the enhanced efficacy of diabetic wound healing, with in vivo studies demonstrating increased healing efficiency following a single application, and more in general an effective strategy toward high-catalytic and stable nanozymes.

Achievements and challenges in glucose oxidase-instructed multimodal synergistic antibacterial applications

Glucose oxidase (GOx) with unique catalytic properties and inherent biocompatibility can effectively oxidize both endogenous and exogenous glucose with oxygen (O2) into gluconic acid and hydrogen peroxide (H2O2). Accordingly, the GOx-based catalytic chemistry offers new possibilities for designing and constructing multimodal synergistic antibacterial systems. The consumption of glucose permanently downregulates bacterial cell metabolism by blocking essential energy supplies, inhibiting their growth and survival. Additionally, the production of gluconic acid could downregulates the pH within the bacterial infection microenvironment, enhancing the production of hydroxyl radicals (∙OH) from H2O2 via enhanced Fenton or Fendon-like reactions and triggering the pH-responsive release of drugs. Furthermore, the generated H2O2 in situ avoids the addition of exogenous hydrogen peroxide. Therefore, it is possible to design GOx-based multimodal antibacterial synergistic therapies by combining GOx-instructed cascade reactions with other therapeutic approaches such as chemodynamic therapies (CDT), hypoxia-activated prodrugs, photosensitizers, and stimuli-responsive drug release. Such multimodal strategies are expected to exhibit better therapeutic effects than single therapeutic modes. This tutorial review highlights recent advancements in GOx-instructed multimodal synergistic antibacterial systems, focusing on design philosophy and construction strategies. Current challenges and future prospects for advancing GOx-based multimodal antibacterial synergistic therapies are discussed.

Single-Atom Cu Anchored on Carbon Nitride as a Bifunctional Glucose Oxidase and Peroxidase Nanozyme for Antibacterial Therapy

A very promising strategy to avoid bacterial drug resistance is to replace antibiotics with artificial nanozymes, but this has not yet been translated to the clinic. Here, we construct a single-atom nanozyme using graphitic carbon nitride nanosheets modified by copper (Cu-g-C3N4). This Cu-g-C3N4 nanosheet possesses both glucose oxidase-like and peroxidase-like activities responsible for reactive-oxygen-species generation by a cascade reaction to eradicate Gram-positive and Gram-negative multidrug-resistant bacteria. Cu-g-C3N4 is introduced into polycaprolactone (PCL) by electrospinning to obtain (Cu-g-C3N4/PCL) nanofibers, which can be used as a dressing for bacterially infected wounds. It is demonstrated that Cu-g-C3N4/PCL nanofiber dressings can eradicate bacterial infections and accelerate wound healing in a mouse model with a skin wound.

Recent Development of Nanozymes for Combating Bacterial Drug Resistance: A Review

The World Health Organization has warned that without effective action, deaths from drug-resistant bacteria can exceed 10 million annually, making it the leading cause of death. Conventional antibiotics are becoming less effective due to rapid bacterial drug resistance and slowed new antibiotic development, necessitating new strategies. Recently, materials with catalytic/enzymatic properties, known as nanozymes, have been developed, inspired by natural enzymes essential for bacterial eradication. Unlike recent literature reviews that broadly cover nanozyme design and biomedical applications, this review focuses on the latest advancements in nanozymes for combating bacterial drug resistance, emphasizing their design, structural characteristics, applications in combination therapy, and future prospects. This approach aims to promote nanozyme development for combating bacterial drug resistance, especially towards clinical translation.

Targeted Management of Diabetic Osteoporosis by Biocatalytic Cascade Reaction Nanoplatform

Diabetic osteoporosis (DOP) is a chronic complication of diabetes mellitus (DM) that impairs bone health, and effective management of DOP remains a formidable challenge. In this study, we developed a biocatalytic cascade nanoplatform, GOx@SrCaP-CAT-Tet, offering osteogenic, angiogenic, and anti-inflammatory activities for targeted DOP management. The platform includes glucose oxidase (GOx) and catalase (CAT), encapsulated in strontium-doped calcium phosphate (SrCaP), converting glucose into gluconic acid and hydrogen peroxide (H2O2), alleviating the hyperglycemia and promoting hypoxia-induced vascularization. Both the generated H2O2 and any overabundance of H2O2 in the DOP microenvironment can be scavenged by CAT, thus relieving inflammation. Via a surface modified with tetracycline (Tet) for bone targeting, the release of Sr2+, Ca2+, and PO43- can stimulate osteogenesis and suppress osteoclastogenesis, thereby hastening bone formation and reversing osteoporosis. This nanoplatform shows promise in managing DOP both in vitro and in vivo. Our findings open a new horizon for managing DOP through biocatalytic cascade reactions.

Glucose oxidase: An emerging multidimensional treatment option for diabetic wound healing

The healing of diabetic skin wounds is a complex process significantly affected by the hyperglycemic environment. In this context, glucose oxidase (GOx), by catalyzing glucose to produce gluconic acid and hydrogen peroxide, not only modulates the hyperglycemic microenvironment but also possesses antibacterial and oxygen-supplying functions, thereby demonstrating immense potential in the treatment of diabetic wounds. Despite the growing interest in GOx-based therapeutic strategies in recent years, a systematic summary and review of these efforts have been lacking. To address this gap, this review article outlines the advancements in the application of GOx and GOx-like nanozymes in the treatment of diabetic wounds, including reaction mechanisms, the selection of carrier materials, and synergistic therapeutic strategies such as multi-enzyme combinations, microneedle structures, and gas therapy. Finally, the article looks forward to the application prospects of GOx in aiding the healing of diabetic wounds and the challenges faced in translating these innovations to clinical practice. We sincerely hope that this review can provide readers with a comprehensive understanding of GOx-based diabetic treatment strategies, facilitate the rigorous construction of more robust multifunctional therapeutic systems, and ultimately benefit patients with diabetic wounds.

Glucose-Responsive Insulin Delivery via Surface-Functionalized Titanium Dioxide Nanoparticles: A Promising Theragnostic against Diabetes Mellitus

Glucose-dependent insulin delivery systems have been recognized as a promising approach for controlling blood sugar levels in individuals with diabetes mellitus (DM). Recently, titanium dioxide nanoparticles have garnered huge attention in scientific research for their small size and effective drug delivery capabilities. In this study, we developed alizarin (AL)-capped phenylboronic acid (PBA)-functionalized titanium dioxide nanoparticles (TiO2) for glucose-sensitive insulin delivery (TiO2-PBA-INS-AL) aiming to manage both blood sugar levels and its associated organ pathology in DM. The synthesized nanoparticles demonstrated favorable loading capacity as well as high insulin encapsulation efficiency. Initial studies demonstrated glucose-responsive insulin release from TiO2-PBA-INS-AL in a cell-free environment upon exposure to different glucose concentrations. Notably, in vitro experiments revealed that insulin release from TiO2-PBA-INS-AL was more effective in muscle cells (primary glucose storage cells) compared to lung cells when subjected to different glucose concentrations (5.5-25 mM), indicating a glucose-sensitive intracellular insulin delivery mechanism. Furthermore, treatment with TiO2-PBA-INS-AL significantly enhanced GLUT4 translocation and glucose utilization in muscle cells treated with sodium palmitate (PA, 0.75 mM), compared to treatments with TiO2 or insulin alone. In diabetic animal models, a single oral dose of TiO2-PBA-INS-AL maintained normoglycemia for up to 12 h, indicating a significant improvement over subcutaneous or oral insulin treatment. Oral administration of TiO2-PBA-INS-AL also increased insulin bioavailability in both serum and muscle tissue compared to other administration methods. Besides, TiO2-PBA-INS-AL treatment showed no toxicity against both in vitro and in vivo models. Taken together, this nanocarrier-based drug delivery system mimics the natural regulation of insulin secretion in a noninvasive manner, enhancing patient adherence, reducing the risk of hyperglycemia, and improving diabetes management.

Electrical Microneedles for Wound Treatment

Electrical stimulation has been hotpot research and provoked extensive interest in a broad application such as wound closure, tissue injury repair, and nerve engineering. In particular, immense efforts have been dedicated to developing electrical microneedles, which demonstrate unique features in terms of controllable drug release, real-time monitoring, and therapy, thus greatly accelerating the process of wound healing. Here, a review of state-of-art research concerning electrical microneedles applied for wound treatment is presented. After a comprehensive analysis of the mechanisms of electrical stimulation on wound healing, the derived three types of electrical microneedles are clarified and summarized. Further, their applications in wound healing are highlighted. Finally, current perspectives and directions for the development of future electrical microneedles in improving wound healing are addressed.

Multifunctional Porous Bilayer Artificial Skin for Enhanced Wound Healing

Meeting the exacting demands of wound healing encompasses rapid coagulation, superior exudate absorption, high antibacterial efficacy, and imperative support for cell growth. In this study, by emulating the intricate structure of natural skin, we prepare a multifunctional porous bilayer artificial skin to address these critical requirements. The bottom layer, mimicking the dermis, is crafted through freeze-drying a gel network comprising carboxymethyl chitosan (CMCs) and gelatin (GL), while the top layer, emulating the epidermis, is prepared via electrospinning poly(l-lactic acid) (PLLA) nanofibers. With protocatechuic aldehyde and gallium ion complexation (PA@Ga) as cross-linking agents, the bottom PA@Ga-CMCs/GL layer featured an adjustable pore size (78-138 μm), high hemostatic performance (67s), and excellent bacterial inhibition rate (99.9%), complemented by an impressive liquid-absorbing capacity (2000% swelling rate). The top PLLA layer, with dense micronanostructure and hydrophobic properties, worked as a shield to effectively thwarted liquid or bacterial penetration. Furthermore, accelerated wound closure, reduced inflammatory responses, and enhanced formation of hair follicles and blood vessels are achieved by the porous artificial skin covered on the surface of wound. Bilayer artificial skin integrates the advantages of nanofibers and freeze-drying porous materials to effectively replicate the protective properties of the epidermal layer of the skin, as well as the cell migration and tissue regeneration of the dermis. This bioabsorbable artificial skin demonstrates structural and functional comparability to real skin, which would advance the field of wound care through its multifaceted capabilities.

Application of sodium sulfobutylether-β-cyclodextrin based on encapsulation

Sodium Sulfobutylether-β-cyclodextrin (SBE-β-CD) is a derivative of β-cyclodextrin, characterized by its stereo structure, which closely resembles a truncated cone with a hydrophobic internal cavity. The solubility of insoluble substances within the hydrophobic cavity is significantly enhanced, reducing contact between the guest and the environment. Consequently, SBE-β-CD is frequently employed as a co-solvent and stabilizer. As the research progresses, it has been observed that the inclusion of SBE-β-CD is reversible and competitive. Besides, some inclusion complexes undergo distinct physicochemical property alterations compared to the guests. Additionally, certain guests exhibit varying inclusions with SBE-β-CD at different concentrations. These features have contributed to the expanding applications. SBE-β-CD finds widespread application in pharmaceutics as a protective agent and pKa regulator, in pharmaceutical analysis as a chiral substance separator, and in biomedical engineering for encapsulating dyes and modifying sensors. The article will elaborate in detail on the physicochemical properties of SBE-β-CD, encapsulation principles, and factors influencing the formation of inclusion complexes. Furthermore, the review focuses on the application of SBE-β-CD through encapsulation in pharmaceutics, pharmaceutical analysis, and biomedical engineering. Finally, the prospects and potential applications of SBE-β-CD are discussed.

Unimolecular Cascaded Multienzyme Conjugates Modulate the Microenvironment of Diabetic Wound to Promote Healing

An abnormal microenvironment underlies poor healing in chronic diabetic chronic wounds. However, effectively modulating the microenvironment of the diabetic wound remains a great challenge due to sustained oxidative stress and chronic inflammation. Here, we present a unimolecular enzyme-polymer conjugate that demonstrates excellent multienzymatic cascade activities. The cascaded enzyme conjugates (CECs) were synthesized by grafting poly(N-acryloyl-lysine) (pLAAm) from the glycan moieties of glucose oxidase (GOx) via glycan-initiated polymerization. The resulting CECs exhibited multiple enzymatic properties of GOx, superoxide dismutase mimic, and catalase mimic activities simultaneously. The CECs facilitated the depletion of high blood glucose, ROS scavenging, bacteria-killing, anti-inflammatory effects, and sustained oxygen generation, which restored the microenvironment in diabetic wounds. In vivo results from a diabetic mouse model confirmed the capacity and efficiency of the cascade reaction for diabetic wound healing. Our findings demonstrate that the three-in-one enzyme-polymer conjugates alone can modulate the diabetic microenvironment for wound healing.

Photosynthetic and Self-Draining Biohybrid Dressing for Accelerating Healing of Diabetic Wound

Wound healing is a well-orchestrated progress associated with angiogenesis, epithelialization, inflammatory status, and infection control, whereas these processes are seriously disturbed in diabetic wounds. In this study, a biohybrid dressing integrating the inherent ability of Bromeliad leaf (photosynthesis and self-draining) with the therapeutic effect of artificial materials (glucose-degrading and ROS-scavenging) is presented. The dressing consists of double-layered structures as follows: 1) Outer layer, a Bromeliad leaf substrate full of alginate hydrogel-immobilized glucose oxidase (GOx@Alg@Bromeliad substrate, abbreviated as BGA), can generate oxygen to guarantee the GOx-catalyzed glucose oxidation by photosynthesis, reducing local hyperglycemia to stabilize hypoxia inducible factor-1 alpha (HIF-1α) for angiogenesis and producing hydrogen peroxide for killing bacteria on the surface of wound tissue. The sophisticated structure of the leaf drains excessive exudate away via transpiration-mimicking, preventing skin maceration and impeding bacterial growth. 2) Inner layer, microneedles containing catalase (CAT-HA MNs, abbreviated as CHM), reduces excessive oxidative stress in the tissue to promote the proliferation of fibroblasts and inhibits proinflammatory polarization of macrophages, improving re-epithelialization of diabetic wounds. Together, the biohybrid dressing (BGA-CHM, abbreviated as BCHM) can enhance angiogenesis, strengthen re-epithelialization, alleviate chronic inflammation, and suppress bacterial infection, providing a promising strategy for diabetic wound therapy.

Chaotropic Effect-Induced Self-Assembly of the Malachite Green and Boron Cluster for Toxicity Regulation and Photothermal Therapy

Malachite green (MG), a toxic antibacterial agent, is widely used in the farming industry. Effectively regulating the biotoxicity of this highly water-soluble cationic dye is challenging. Here, we present a novel strategy to reduce the biotoxicity of MG through the self-assembly of MG and the closo-dodecaborate cluster ([B12H12]2-) driven by the chaotropic effect. [B12H12]2- and MG in an aqueous solution can rapidly form an insoluble cubic-type supramolecular complex (B12-MG), and the original toxicity of MG is completely suppressed. Surprisingly, this supramolecular complex, B12-MG, has a strong UV-vis absorption peak at 600-800 nm and significant photothermal conversion efficiency under 660 nm laser irradiation. On this basis, B12-MG, the supramolecular complex, can be used as an efficient photothermal agent for antimicrobial photothermal therapy (PTT) both in vitro and in vivo. As a molecular chaperone of MG, [B12H12]2- not only can be applied as an antidote to regulate the biotoxicity of MG but also provides a novel method for the construction of photothermal agents for PTT based on the chaotropic effect.

CuFe Layered Double Hydroxide as Self-Cascade Nanoreactor for Efficient Antibacterial Therapy

Nanozyme-induced reactive oxygen species (ROS)-dependent catalytic therapy has been developed into a powerful strategy against bacterial wound infections. However, the limited endogenous supply or instability of H2O2, the reliance on external stimuli for the generation of ROS, and the highly expressed glutathione (GSH) level make it a challenge to achieve high-performance therapeutic efficiency. In this work, a facile therapeutic strategy against bacterial infections with pristine CuFe layered double hydroxide (LDH) as the self-cascade nanoreactor is proposed without modification or additional energy input. CuFe LDH with an oxidase-like feature can catalyze the generation of multiple ROS, such as 1O2, ·O2-, and H2O2. And the self-generated H2O2 in the cascade nanoreactor could be further in situ transformed to ·OH owing to the peroxidase-like activity. As a result, the cell membrane of bacteria is destroyed, leading to death. Furthermore, its ultrahigh enzyme-like activity of CuFe LDH could effectively promote the breakdown of the biofilm structure. Additionally, the Cu2+-mediated GSH exhaustion of CuFe LDH further avoids the consumption of oxidized ROS and thereby significantly improves the sterilization effect. Finally, the as-prepared CuFe LDH with negligible side effects on normal tissues can be successfully used to eliminate the methicillin-resistant Staphylococcus aureus-infected wounds and accelerate their healing in the mouse model, which paves a new avenue as an antibacterial agent for clinical anti-infective treatment.

Guanosine-driven hyaluronic acid-based supramolecular hydrogels with peroxidase-like activity for chronic diabetic wound treatment

Guanosine is often used to construct supramolecular hydrogels due to its self-assembly properties, however, the high temperature and strong alkaline construction methods greatly limit its application in biomedical fields. In this work, a guanosine-driven hyaluronic acid-based supramolecular hydrogel was developed under mild condition by employing phenylboronic acid-functionalized hyaluronic acid (HA-PBA) backbone and guanosine molecules. Guanosines self-assembled into G-quartet planes under potassium ion conditions, and formed boronic ester bonds with HA-PBA, which induced rapid formation of dynamically cross-linked hydrogels. Hemin was then binding to the G-quartet plane via π-π interactions in the hydrogels, which exhibited peroxidase activity and were highly effective in killing bacteria by generating hydroxyl radicals in the presence of H2O2. Furthermore, glucose oxidase (GOx) was incorporated into the hydrogels and the HP/G@hemin@GOx hydrogels showed good antibacterial properties, modulation of wound glucose and ROS level, and good therapeutic efficacy for diabetic chronic wounds. Overall, the self-assembly of guanosine has been shown for the first time to be a feasible method for constructing natural polymer-based supramolecular hydrogels. This guanosine-driven HA-based supramolecular hydrogel can act as a potential wound dressing for chronic diabetic wound treatment. STATEMENT OF SIGNIFICANCE: Chronic wound repair remains an unsolved clinical challenge. Herein, we propose to utilize phenylboronic acid-modified hyaluronic acid and guanosine to construct supramolecular gels with peroxidase activity for chronic wound treatment. The self-assembly behavior of guanosine drives the natural macromolecular backbone to form the hydrogel, and the proposed method simplifies the gelation conditions and improves its biosafety. The G-quartets formed by the self-assembly of guanosine can act as the loading site for hemin. G-quartet/hemin complex imported peroxidase activity to the hydrogels, endowing them with the ability to kill bacteria and regulate ROS levels of cells in the wound site. This guanosine-driven supramolecular hydrogel significantly increased the rate of wound healing in diabetic mice, promising a new strategy for chronic wound treatment.

Recent advances in the design of afterglow materials: mechanisms, structural regulation strategies and applications

Afterglow materials are attracting widespread attention owing to their distinctive and long-lived optical emission properties which create exciting opportunities in various fields. Recent research has led to the discovery of many new afterglow materials featuring high photoluminescence quantum yields (PLQY) and lifetimes of up to several hours under ambient conditions. Afterglow materials are typically categorized according to their luminescence mechanism, such as long-persistent luminescence (LPL), room temperature phosphorescence (RTP), or thermally activated delayed fluorescence (TADF). Through rational design and novel synthetic strategies to modulate spin-orbit coupling (SOC) and populate triplet exciton states (T1), luminophores with long lifetimes and bright afterglow characteristics can be realized. Initial research towards afterglow materials focused mainly on pure inorganic materials, many of which possessed inherent disadvantages such as metal toxicity or low energy emissions. In recent years, organic-inorganic hybrid afterglow materials (OIHAMs) have been developed with high PLQY and long lifetimes. These hybrid materials exploit the tunable structure and easy processing of organic molecules, as well as enhanced SOC and intersystem crossing (ISC) processes involving heavy atom dopants, to achieve excellent afterglow performance. In this review, we begin by briefly discussing the structure and composition of inorganic and organic-inorganic hybrid afterglow materials, including strategies for regulating their lifetime, PLQY and luminescence wavelength. The specific advantages of organic-inorganic hybrid afterglow materials, including low manufacturing costs, diverse molecular/electronic structures, tunable structures and optical properties, and compatibility with a variety of substrates, are emphasized. Subsequently, we discuss in detail the fundamental mechanisms used by afterglow materials, their classification, design principles, and end applications (including sensing, anticounterfeiting, and photoelectric devices, among others). Finally, existing challenges and promising future directions are discussed, laying a platform for the design of afterglow materials for specific applications.

Glucose oxidase and metal catalysts combined tumor synergistic therapy: mechanism, advance and nanodelivery system

Cancer has always posed a significant threat to human health, prompting extensive research into new treatment strategies due to the limitations of traditional therapies. Starvation therapy (ST) has garnered considerable attention by targeting the primary energy source, glucose, utilized by cancer cells for proliferation. Glucose oxidase (GOx), a catalyst facilitating glucose consumption, has emerged as a critical therapeutic agent for ST. However, mono ST alone struggles to completely suppress tumor growth, necessitating the development of synergistic therapy approaches. Metal catalysts possess enzyme-like functions and can serve as carriers, capable of combining with GOx to achieve diverse tumor treatments. However, ensuring enzyme activity preservation in normal tissue and activation specifically within tumors presents a crucial challenge. Nanodelivery systems offer the potential to enhance therapy effectiveness by improving the stability of therapeutic agents and enabling controlled release. This review primarily focuses on recent advances in the mechanism of GOx combined with metal catalysts for synergistic tumor therapy. Furthermore, it discusses various nanoparticles (NPs) constructs designed for synergistic therapy in different carrier categories. Finally, this review provides a summary of GOx-metal catalyst-based NPs (G-M) and offers insights into the challenges associated with G-M therapy, delivery design, and oxygen (O2) supply.

Double-Layer Hydrogel with Glucose-Activated Two-Stage ROS Regulating Properties for Programmed Diabetic Wound Healing

Slow healing of wounds induces great pain in diabetic patients. However, developing new approaches to promote diabetic wound healing is still one of the toughest challenges in the medical field. Here, we constructed a new double-layer hydrogel to effectively regulate reactive oxygen species (ROS) on the wound and promote diabetic wound healing. The inner layer contains glucose oxidase (Gox), ferrocene-modified quaternary ammonium chitosan (Fc-QCs), and poly(β-cyclodextrin) (Pβ-CD), which is used to generate hydroxyl radicals (•OH) for antibacterial in the early stage of wound healing and collapses gradually. The outer layer is composed of gelatin and dopamine. In the later stage of wound healing, the outer layer contacts the skin, which is beneficial for ROS clearance on the wound. Antibacterial, ROS scavenging, and wound healing experiments have shown that the double-layer hydrogel possesses two-stage ROS regulating properties for programmed diabetic wound healing. In conclusion, it will be one of the most potential dressings for treating diabetic wounds in the future.

Supramolecular Nanozyme System Based on Polydopamine and Polyoxometalate for Photothermal-Enhanced Multienzyme Cascade Catalytic Tumor Therapy

The advent of enzyme-facilitated cascade events in which endogenous substrates within the human body are used to generate reactive oxygen species (ROS) has spawned novel cancer treatment possibilities. In this study, a supramolecular cascade catalytic nanozyme system was successfully developed, exhibiting photothermal-enhanced multienzyme cascade catalytic and glutathione (GSH) depletion activities and ultimately triggering the apoptosis-ferroptosis synergistic tumor therapy. The nanozyme system was fabricated using β-cyclodextrin-functionalized polydopamine (PDA) as the substrate, which was then entangled with polyoxometalate (POM) via electrostatic forces and assembled with adamantane-grafted hyaluronic acid and glucose oxidase (GOx) via host-guest supramolecular interaction for tumor targeting and GOx loading. The catalytic function of GOx facilitates the conversion of glucose to H2O2 and gluconic acid. In turn, this process affirms the propitious generation of hydroxyl radical (•OH) through the POM-mediated cascade catalysis. Additionally, the POM species actively deplete the intracellular GSH pool, initiating a cascade catalytic tumor therapy. In addition, the PDA-POM-mediated photothermal hyperthermia boosted the cascade catalytic effect and increased ROS production. This confers considerable promise for photothermal therapy (PTT)/nanocatalytic cancer therapy on supramolecular nanozyme systems. The in vitro and in vivo antitumor efficacy studies demonstrated that the supramolecular cascade catalytic nanozyme system was effective at reducing tumor development while maintaining an acceptable level of biocompatibility. Henceforth, this study is to widen the scope of cascade catalytic nanoenzyme production using supramolecular techniques, as well as endeavor to delineate a prospective pathway for the application of PTT-enhanced nanocatalytic tumor therapy.

Glucose Oxidase Driven Hydrogen Sulfide-Releasing Nanocascade for Diabetic Infection Treatment

Diabetic ulcers have received much attention in recent years due to their high incidence and mortality, motivating the scientific community to develop various strategies for such chronic disease treatments. However, the therapeutic outcome of these approaches is highly compromised by invasive bacteria and a severe inflammatory microenvironment. To overcome these dilemmas, microenvironment-responsive self-delivery glucose oxidase@manganese sulfide (GOx@MnS) nanoparticles (NPs) are developed by one-step biomineralization. When they encounter the high glucose level in the ulcer site, GOx particles catalyze glucose to decrease the local pH and trigger the steady release of both manganese ions (Mn²⁺) and hydrogen sulfide (H₂S). Mn²⁺ reacts with hydrogen peroxide to generate hydroxyl radicals for the elimination of bacterial infection; meanwhile, H₂S is able to suppress the inflammatory response and accelerate diabetic wound healing through macrophage polarization. The excellent biocompatibility, strong bactericidal activity, and considerable immunomodulatory effect promise GOx@MnS NPs have great therapeutic potential for diabetic wound treatment.

Fabrication of Biomimetic Cascade Nanoreactor Based on Covalent Organic Framework Capsule for Biosensing

The cooperation of biocatalysis and chemocatalysis in a catalytic cascade reaction has received extensive attention in recent years, whereas its practical applications are still hampered due to the fragility of the enzymes, poor compatibility between the carriers and enzymes, and limited catalytic efficiency. Herein, a biomimetic cascade nanoreactor (GOx@COFs@Os) was presented by integrating glucose oxidase (GOx) and Os nanozyme with covalent organic framework (COF) capsule using metal-organic framework (ZIF-90) as a template. The obtained GOx@COFs@Os capsule provided a capacious microenvironment to retain the conformational freedom of GOx for maintaining its activity, wherein the enzyme activity of GOx in COF capsules was equal to 92.9% of the free enzyme and was 1.88-folds higher than that encapsulated in ZIF-90. Meanwhile, the COF capsule could protect the GOx against incompatible environments (high temperature, acid, and organic solvents), resulting in improved stability of the packaged enzymes. Moreover, the COF capsule with great pore structure significantly improved the affinity to substrates and facilitated efficient mass transfer, which achieved 2.19-folds improvement in catalytic efficiency than the free cascade system, displaying the great catalytic performance in the cascade reaction. More importantly, the biomimetic cascade capsule was successfully employed for glucose monitoring, glutathione sensing, and bisphenol S detection in the immunoassay as a proof-of-concept. Our strategy provided a new avenue in the improvement of biocatalytic cascade performance to encourage its wide applications in various fields.

On-Demand Free Radical Release by Laser Irradiation for Photothermal-Thermodynamic Biofilm Inactivation and Tooth Whitening

Dental diseases associated with biofilm infections and tooth staining affect billions of people worldwide. In this study, we combine photothermal agents (MoS₂@BSA nanosheets, MB NSs), a thermolysis free-radical initiator (AIPH), and carbomer gel to develop laser-responsive hydrogel (MBA-CB Gel) for biofilm inactivating and tooth whitening. Under a physiological temperature without laser irradiation, MB NSs can eliminate free radicals generated from the slow decomposition of AIPH due to their antioxidative activity, thereby avoiding potential side effects. A cytotoxicity study indicates that MB NSs can protect mammalian cells from the free radicals released from AIPH without laser irradiation. Upon exposure to laser irradiation, MB NSs promote the rapid decomposition of AIPH to release free radicals by photothermal effect, suggesting their on-demand release ability of free radicals. In vitro experimental results show that the bacteria inactivation efficiency is 99.91% (3.01 log units) for planktonic Streptococcus mutans (S. mutans) and 99.98% (3.83 log units) for planktonic methicillin-resistant Staphylococcus aureus (MRSA) by the mixed solution of MB NSs and AIPH (MBA solution) under 808 nm laser irradiation (1.0 W/cm², 5 min). For S. mutans biofilms, an MBA solution can inactivate 99.97% (3.63 log units) of the bacteria under similar laser irradiation conditions. Moreover, MBA-CB Gel can whiten an indigo carmine-stained tooth under laser irradiation after 60 min of laser treatment, and the color difference (ΔE) in the teeth of the MBA-CB Gel treatment group was 10.9 times that of the control group. This study demonstrates the potential of MBA-CB Gel as a promising platform for biofilm inactivation and tooth whitening. It is worth noting that, since this study only used stained models of extracted teeth, the research results may not fully reflect the actual clinic situation. Future clinical research needs to further validate these findings.

A versatile supramolecular nanoagent for three-pronged boosting chemodynamic therapy

Chemodynamic therapy (CDT) utilizing toxic hydroxyl radicals (·OH) to kill cancer cells exhibits huge potentiality in antitumor treatment. However, inadequate acidity, insufficient hydrogen peroxide (H₂O₂) amount, and overexpressed reduced glutathione (GSH) inside cancer cells severely restrict the efficacy of CDT. Although numerous efforts have been made, fabricating a versatile CDT material for surmounting these obstacles simultaneously is still a great challenge, especially for supramolecular materials owing to lacking an active metal unit for the Fenton reaction. Here, we intriguingly proposed a powerful supramolecular nanoagent (GOx@GANPs) based on the host-guest interaction between pillar[6]arene and ferrocene for all-sided boosting CDT efficacy via in situ cascade reactions. GOx@GANPs could stimulate intracellular glucose conversion into H⁺ and H₂O₂ to optimize the in situ Fenton reaction conditions and continuously produce sufficient •OH. Meanwhile, consumption of the original intracellular GSH pool and inhibition of GSH regeneration were synchronously achieved through the GSH-responsive gambogic acid prodrug and cutting off adenosine triphosphate (ATP) supply for GSH resynthesis, respectively. This complete GSH exhausting characteristic of GOx@GANPs effectively suppressed •OH elimination, ultimately resulting in a superior CDT effect. Furthermore, GOx@GANPs also produced synergistic effects of starvation therapy, chemotherapy, and CDT, exhibiting low toxicity toward normal tissues. Thus, this work introduces a valuable way for optimizing and elevating CDT efficiency and synergistic treatment of tumors.

Multi-functional nanogel with cascade catalytic performance for treatment of diabetic oral mucosa ulcer

Introduction: Diabetic oral mucosa ulcers face challenges of hypoxia, hyperglycemia and high oxidative stress, which result in delayed healing process. Oxygen is regarded as an important substance in cell proliferation, differentiation and migration, which is beneficial to ulcer recovery. Methods: This study developed a multi-functional GOx-CAT nanogel (GCN) system for the treatment of diabetic oral mucosa ulcers. The catalytic activity, ROS scavenge and oxygen supply ability of GCN was validated. The therapeutic effect of GCN was verified in the diabetic gingival ulcer model. Results: The results showed that the nanoscale GCN was capable of significantly eliminating intracellular ROS, increasing intracellular oxygen concentration and accelerating cell migration of human gingival fibroblasts, which could promote diabetic oral gingival ulcer healing in vivo by alleviating inflammation and promoting angiogenesis. Discussion: This multifunctional GCN with ROS depletion, continuous oxygen supply and good biocompatibility, which might provide a novel therapeutic strategy for effective treatment of diabetic oral mucosa ulcers.

Biomimetic Enzyme Cascade Structural Color Hydrogel Microparticles for Diabetic Wound Healing Management

Hard-healing diabetic wound brings burgeoning physical and mental burdens to patients. Current treatment strategies tend to achieve multistage promotion and real-time reporting to facilitate wound management. Herein, a biomimetic enzyme cascade inverse opal microparticles system for wound healing, which is intergated with glucose oxidase (GOD) and copper peroxide (CP). Such microparticles are composed of biofriendly hyaluronic acid methacryloyl (HAMA) and pH-responsive acrylic acid (AA), which provided abundant binding sites and spaces for chemical immobilizing and physical doping of enzymes and metal bioinorganics. When the cascade catalytic system is applied on wound sites, hyperglycemia environment would serve as a hydrogen peroxide (H₂ O₂ ) generator through GOD catalysis, while acidic environment triggers the decomposition of CP, further catalyzing H₂ O₂ to generate reactive oxygen species (ROS). Additionally, the distinctive structural color of the microparticles can visually reflect the wound pH and intelligently estimate the healing state. It is demonstrated that such microparticle systems exhibit excellent broad-spectrum antibacterial and angiogenesis-promoting properties, as well as significant real-time reporting ability for wound healing. These features indicate that enzyme cascade structural color microparticles possess valuable potential in wound healing and related field.

Physical Contact-Triggered In Situ Reactivation of Antibacterial Hydrogels

In situ reactivation of hydrogels remains a long-standing key challenge in chemistry and materials science. Herein, we first report an ultraconvenient in situ renewable antibacterial hydrogel prepared via a facile physical contact-triggered strategy based on an ultrafast chlorine transfer pathway. We discover that the as-proposed hydrogel with a programmable 3D network cross-linked by noncovalent bonds and physical interactions can serve as a smart platform for selective active chlorine transfer at the hydrogel/hydrogel interface. Systematic experiments and density functional theory prove that the N-halamine glycopolymers integrated into the hydrogel system work as a specific renewable biocide, permitting the final hydrogel to be recharged in situ within 1 min under ambient conditions. Due to its strength and durability, pathogen specificity, and biocompatibility, coupled with its rapid in situ reactivation, this antibacterial hydrogel holds great potential for in vivo biomedical use and circulating water disinfection. We envision this proposed strategy will pave a new avenue for the development of in situ renewable smart hydrogels for real-world applications.

Light-triggered Modulation of Supramolecular Chirality

Dynamically controlling the supramolecular chirality is of great significance in development of functional chiral materials, which is thus essential for the specific function implementation. As an external energy input, light is remote and accurate for modulating chiral assemblies. In non-polarized light control, some photochemically reactive units (e. g., azobenzene, ɑ-cyanostilbene, spiropyran, anthracene) or photo-induced directionally rotating molecular motors were designed to drive chiral transfer or amplification. Besides, photoexcitation induced assembly based physical approach was also explored recently to regulate supramolecular chirality beyond photochemical reactions. In addition, circularly polarized light was applied to induce asymmetric arrangement of organic molecules and asymmetric photochemical synthesis of inorganic metallic nanostructures, in which both wavelength and handedness of circularly polarized light have effects on the induced supramolecular chirality. Although light-triggered chiral assemblies have been widely applied in photoelectric materials, biomedical fields, soft actuator, chiral catalysis and chiral sensing, there is a lack of systematic review on this topic. In this review, we summarized the recent studies and perspectives in the constructions and applications of light-responsive chiral assembled systems, aiming to provide better knowledge for the development of multifunctional chiral nanomaterials.

Novel ROS-scavenging hydrogel with enhanced anti-inflammation and angiogenic properties for promoting diabetic wound healing

Accelerating angiogenesis of diabetic wounds is crucial to promoting wound healing. Currently, vascular endothelial growth factor (VEGF), an angiogenesis-related bioactive molecule, is widely used in clinic to enhance wound angiogenesis, but it faces problems of inactivation and low utilization due to harsh microenvironment. Here, we developed a novel reactive oxygen species (ROS)-scavenging hydrogel aimed to polarize macrophages toward an anti-inflammatory phenotype, inducing efficient angiogenesis in diabetic wounds. This composite hydrogel with good biosafety and mechanical properties showed sustainable release of bioactive VEGF. Importantly, it could significantly reduce ROS level and rapidly improve wound microenvironment, which ensured the activity of VEGF in vitro and in vivo and successful healing eventually. At the same time, the composite hydrogel exhibited excellent antibacterial properties. In vivo results confirmed good anti-inflammatory, stimulated vascularization and accelerated wound healing attributed to the novel ROS-scavenging hydrogel, which might serve as a promising wound dressing in diabetic wound healing.

GOx-encapsulated iron-phenolic networks power catalytic cascade to eradicate bacterial biofilms

Bacterial biofilms, especially ones caused by multi-drug resistant strains, are increasingly posing a significant threat to human health. Inspired by nature, we report the fabrication of glucose oxidase-loaded iron-phenolic networks that can power the cascade reaction to generate free radicals to eradicate bacterial biofilms. A soft template, sodium deoxycholate, is employed to guarantee glucose oxidase activity during encapsulation, yielding the porous nanocomplexes after removing the template. The porous nature of nanocomplexes, characterized via transmission electron microscopy, N₂ adsorption isotherms, and thermogravimetric analysis, facilitates the diffusion of substrates and products during the cascade reaction and protects glucose oxidase from protease attack. Our optimized nanocomplexes (Fe-GA/GOx) could efficiently kill drug-resistant ESKAPE pathogens, including the clinically isolated strains and eradicate their biofilms. In this regard, Fe-GA/GOx could induce over 90% of the biomass of Klebsiella pneumoniae and Staphylococcus aureus biofilms. In the murine peritonitis infection model induced by Staphylococcus aureus and pneumonia model induced by Klebsiella pneumoniae, our Fe-GA/GOx nanocomplexes could efficiently eradicate the bacteria (over 3-log reduction in colony-forming units) and alleviate the inflammatory response without notable side effects on normal tissues. Therefore, our strategy may provide an efficient alternative treatment to combat bacterial biofilms and address the emergence of drug resistance.