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

Recent advances in smart hydrogels derived from polysaccharides and their applications for wound dressing and healing

Owing to their inherent biocompatibility and biodegradability, hydrogels derived from polysaccharides have emerged as promising candidates for wound management. However, the complex nature of wound healing often requires the development of smart hydrogels---intelligent materials capable of responding dynamically to specific physical or chemical stimuli. Over the past decade, an increasing number of stimuli-responsive polysaccharide-based hydrogels have been developed to treat various types of wounds. While a range of hydrogel types and their versatile functions for wound management have been discussed in the literature, there is still a need for a review of the crosslinking strategies used to create smart hydrogels from polysaccharides. This review provides a comprehensive overview of how stimuli-responsive hydrogels can be designed and made using five key polysaccharides: chitosan, hyaluronic acid, alginate, dextran, and cellulose. Various methods, such as chemical crosslinking, dynamic crosslinking, and physical crosslinking, which are used to form networks within these hydrogels, ultimately determine their ability to respond to stimuli, have been explored. This article further looks at different polysaccharide-based hydrogel wound dressings that can respond to factors such as reactive oxygen species, temperature, pH, glucose, light, and ultrasound in the wound environment and discusses how these responses can enhance wound healing. Finally, this review provides insights into how stimuli-responsive polysaccharide-based hydrogels can be developed further as advanced wound dressings in the future.

Multimodal Synergistic Strategies for Diabetic Wound Healing Using Glucose Oxidase Nanocomposites: Therapeutic Mechanisms and Nanomaterial Design

Diabetic wounds (DWs) are characterized by high blood glucose levels, and one of the primary strategies for regulating blood glucose is the use of glucose oxidase (GOx). This enzyme catalyzes the oxidation of glucose to produce D-gluconic acid, consuming oxygen and generating hydrogen peroxide (H₂O₂) in the process. In DWs, this reaction not only effectively reduces glucose concentrations at the wound site but also provides an antibacterial effect through the release of H₂O₂. Based on this principle, combining glucose oxidase with other therapeutic approaches to develop multimodal wound treatment strategies has garnered significant research attention. Additionally, the abundance of binding sites on the GOx molecular surface enables the construction of multifunctional GOx-based nanocomposites. This review uniquely integrates emerging nanomaterial designs with cascade therapeutic strategies, offering insights into overcoming challenges in diabetic wound healing. Recently, multifunctional nanocomposites have gained attention for integrating multiple therapeutic modalities, relying on cascade mechanisms of multimodal synergistic therapies to tackle complex challenges in DWs treatment. However, there is currently no systematic review that comprehensively elaborates on the construction of these nanocomposites and the specific applications of multimodal treatment strategies in DWs healing. To fill this gap in the field, this review provides a comprehensive overview of these nanomaterials, starting with a systematic exploration of cascade and synergistic therapeutic mechanisms centered on GOx-catalyzed reactions. It highlights applications in photothermal therapy (PTT), photodynamic therapy (PDT), and gas therapy (GT), summarizes the design of nanocarriers, and discusses challenges in DWs healing and future development directions. The findings discussed provide a pathway for the development of clinically viable, cost-effective therapies for chronic wounds.

Magnetic structural color microspheres for the multiplex detection of acute kidney injury biomarkers

BACKGROUND

Acute kidney injury (AKI) is a frequent acute condition that features sharp loss of kidney functions and often leads to severe situations such as end-stage renal disease and even death. The incidence and mortality of AKI in hospitalized patients are high worldwide, and one of the reasons for this poor prognosis is the inability to diagnose AKI promptly. The sensitive and specific assay of biomarkers is considered a promising method for early diagnosis of AKI.

RESULTS

We designed a magnetic-responsive structural colored inverse opal hydrogel microspheres (IOHMs) for the multiplex detection of cystatin C (CysC) and neutrophil gelatinase-associated lipocalin (NGAL), which are two early biomarkers of AKI. The microsphere possessed structural colors for encoding and directional motion ability for improved detection sensitivity and separation efficiency, showing the detection ranges of CysC and NGAL in 10-5000 ng/mL and 10-1000 ng/mL, respectively.

SIGNIFICANCE

The method's accuracy and reliability were consistent with commonly used enzyme-linked immunosorbent assay methods. Therefore, these magnetic IOHMs have a promising application for early AKI diagnosis.

A Narrative Review of Bioactive Hydrogel Microspheres: Ingredients, Modifications, Fabrications, Biological Functions, and Applications

Hydrogel microspheres are important in regenerative medicine and tissue engineering, acting as cargos of cells, drugs, growth factors, bio-inks for 3D printing, and medical devices. The antimicrobial and anti-inflammatory characteristics of hydrogel microspheres are good for treating injured tissues. However, the biological properties of hydrogel microspheres should be modified for optimal treatment of various body parts with different physiological and biochemical environments. In addition, specific preparation methods are required to produce customized hydrogel microspheres with different shapes and sizes for various clinical applications. Herein, the advances in hydrogel microspheres for biomedical applications are reviewed. Synthesis methods for hydrogel precursor solutions, manufacturing methods, and strategies for enhancing the biological functions of these hydrogel microspheres are described. The involvement of bioactive hydrogel microspheres in tissue repair is also discussed. This review anticipates fostering more insights into the design, production, and application of hydrogel microspheres in biomedicine.

Microneedles in diabetic wound care: multifunctional solutions for enhanced healing

Diabetic wounds present a significant challenge in clinical treatment and are characterized by chronic inflammation, oxidative stress, impaired angiogenesis, peripheral neuropathy, and a heightened risk of infection during the healing process. By creating small channels in the surface of the skin, microneedle technology offers a minimally invasive and efficient approach for drug delivery and treatment. This article begins by outlining the biological foundation of normal skin wound healing and the unique pathophysiological mechanisms of diabetic wounds. It then delves into the various types, materials, and preparation processes of microneedles. The focus is on the application of multifunctional microneedles in diabetic wound treatment, highlighting their antibacterial, anti-inflammatory, immunomodulatory, antioxidant, angiogenic and neural repair properties. These multifunctional microneedles demonstrate synergistic therapeutic effects by directly influencing the wound microenvironment, ultimately accelerating the healing of diabetic wounds. The advancement of microneedle technology not only holds promise for enhancing the treatment outcomes of diabetic wounds but also offers new strategies for addressing other chronic wounds.

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.

Plasmonic Supramolecular Nanozyme-Based Bio-Cockleburs for Synergistic Therapy of Infected Diabetic Wounds

Diabetic wounds are a major devastating complication of diabetes due to hyperglycemia, bacterial invasion, and persistent inflammation, and the current antibiotic treatments can lead to the emergence of multidrug-resistant bacteria. Herein, a bimetallic nanozyme-based biomimetic bio-cocklebur (GNR@CeO2@GNPs) is designed and synthesized for diabetic wound management by depositing spiky ceria (CeO2) shells and gold nanoparticles (GNPs) on a gold nanorod (GNR) nanoantenna. The plasmonic-enhanced nanozyme catalysis and self-cascade reaction properties simultaneously boost the two-step enzyme-mimicking catalytic activity of GNR@CeO2@GNPs, leading to a significant improvement in overall therapeutic efficacy rather than mere additive effects. Under the glucose activation and 808 nm laser irradiation, GNR@CeO2@GNPs material captures photons and promotes the transfer of hot electrons from GNR and GNPs into CeO2, realizing a "butterfly effect" of consuming local glucose, overcoming the limited antibacterial efficiency of an individual PTT modality, and providing substantial reactive oxygen species. In vitro and in vivo experiments demonstrate the material's exceptional antibacterial and antibiofilm properties against Gram-negative and Gram-positive bacteria, which can reduce inflammation, promote collagen deposition, and facilitate angiogenesis, thereby accelerating wound healing. This study provides a promising new strategy to develop plasmonic-enhanced nanozymes with a catalytic cascade mode for the antibiotic-free synergistic treatment of infected diabetic wounds.

Application of Drug Delivery System Based on Nanozyme Cascade Technology in Chronic Wound

Chronic wounds are characterized by long-term inflammation, including diabetic ulcers, traumatic ulcers, etc., which provide an optimal environment for bacterial proliferation. At present, antibiotics are the main clinical treatment method for chronic wound infections. However, the overuse of antibiotics may accelerate the emergence of drug-resistant bacteria, which poses a significant threat to human health. Therefore, there is an urgent need to develop new therapeutic strategies for bacterial infections. Nanozyme-based antimicrobial therapy (NABT) is an emerging antimicrobial strategy with broad-spectrum activity and low drug resistance compared to traditional antibiotics. NABT has shown great potential as an emerging antimicrobial strategy by catalyzing the generation of reactive oxygen species (ROS) with its enzyme-like catalytic properties, producing a powerful bactericidal effect without developing drug resistance. Nanozyme-based cascade antimicrobial technology offers a new approach to infection control, effectively improving antimicrobial efficacy by activating cascades against bacterial cell membranes and intracellular DNA while minimizing potential side effects. However, it is worth noting that this technology is still in the early stages of research. This article comprehensively reviews wound classification, current methods for the treatment of wound infection, different types of nanozymes, the application of nanozyme cascade reaction technology in antimicrobial therapy, and future challenges and prospects.

Emerging biomedical technologies for scarless wound healing

Complete wound healing without scar formation has attracted increasing attention, prompting the development of various strategies to address this challenge. In clinical settings, there is a growing preference for emerging biomedical technologies that effectively manage fibrosis following skin injury, as they provide high efficacy, cost-effectiveness, and minimal side effects compared to invasive and costly surgical techniques. This review gives an overview of the latest developments in advanced biomedical technologies for scarless wound management. We first introduce the wound healing process and key mechanisms involved in scar formation. Subsequently, we explore common strategies for wound treatment, including their fabrication methods, superior performance and the latest research developments in this field. We then shift our focus to emerging biomedical technologies for scarless wound healing, detailing the mechanism of action, unique properties, and advanced practical applications of various biomedical technology-based therapies, such as cell therapy, drug therapy, biomaterial therapy, and synergistic therapy. Finally, we critically assess the shortcomings and potential applications of these biomedical technologies and therapeutic methods in the realm of scar treatment.

Glucose activated synergistic cascade therapy of diabetic wound by platinum and glucose oxidase decorated camelina lipid droplets

Hyperglycemia provides a favorable breeding ground for bacteria, resulting in repeated and persistent inflammation of wounds and prolonged healing processes. In this study, platinum (Pt) nanoparticles (NPs) and glucose oxidase (GOx) were decorated on the surface of camelina lipid droplets (OB) linked with hFGF2, forming PGOB through in situ reduction of Pt ions and electrostatic adsorption, respectively. PGOB exhibits cascade enzyme catalytic activity, which can be activated by glucose in diabetic wound tissues. Specifically, GOx on PGOB catalyzes glucose into hydrogen peroxide, which can further decompose into hydroxyl radicals that have higher toxicity for bacterial inactivation. Additionally, glucose decomposition creates a low pH microenvironment, facilitating the cascade catalytic activity that ensures better bacterial suppression within the wound tissues. Furthermore, hFGF2 promotes the proliferation and migration of fibroblasts. Both in vitro and in vivo experiments confirm that PGOB effectively accelerates wound healing processes through bacteria inactivation and tissue regeneration. This study has developed an alternative strategy for glucose-triggered synergistic cascade therapy for diabetic wounds.

Engineering Robust Silver-Decorated calcium peroxide Nano-Antibacterial Platforms for chemodynamic enhanced sterilization

Calcium peroxide (CaO2) is commonly used as a hydrogen peroxide (H2O2) donor to eliminate bacterial infections. However, the rapid dissociation of CaO2 and the explosive release of H2O2 have limited the development of CaO2 in the antibacterial field. Therefore, a series of silver nanoparticles (AgNPs) functionalized bacteria-triggered smart hydrogels (CSA-H) that integrate sustained release of nanoparticles and localized chemodynamic sterilization were constructed. The pH-responsive hydrogel formed through the Schiff base reaction enables the responsive release of CaO2 nanoparticles while simultaneously regulating the concentration of H2O2 within the bacterial infection microenvironment. AgNPs are capable of reacting with H2O2 under mildly acidic conditions to produce hydroxyl radicals with enhanced antimicrobial activity. The antimicrobial results demonstrated that AgNPs functionalized silicon dioxide-coated calcium peroxide (CaO2@SiO2/AgNPs) nanoparticles exhibited enhanced bactericidal activity compared to AgNPs or CaO2 alone. Furthermore, CSA-H hydrogels exhibited significant antibacterial activity against S. aureus and E. coli under the dual effect of AgNPs and pH-driven Fenton-like reactions. This chemodynamic antibacterial platform is environmentally responsive and provides a promising strategy for creating multifunctional hydrogels loaded with nano-enzymes, thus advancing the development of AgNPs in chemodynamic-antibacterial related applications.

Advancing diabetic wound care: The role of copper-containing hydrogels

Diabetic wounds pose a significant challenge in healthcare due to their complex nature and the difficulties they present in treatment and healing. Impaired healing processes in individuals with diabetes can lead to complications and prolonged recovery times. However, recent advancements in wound healing provide reasons for optimism. Researchers are actively developing innovative strategies and therapies specifically tailored to address the unique challenges of diabetic wounds. One focus area is biomimetic hydrogel scaffolds that mimic the natural extracellular matrix, promoting angiogenesis, collagen deposition, and the healing process while also reducing infection risk. Copper nanoparticles and copper compounds incorporated into hydrogels release copper ions with antimicrobial, anti-inflammatory, and angiogenic properties. Copper reduces infection risk, modulates inflammatory response, and promotes tissue regeneration through cell adhesion, proliferation, and differentiation. Utilizing copper nanoparticles has transformative potential for expediting diabetic wound healing and improving patient outcomes while enhancing overall well-being by preventing severe complications associated with untreated wounds. It is crucial to write a review highlighting the importance of investigating the use of copper nanoparticles and compounds in diabetic wound healing and tissue engineering. These groundbreaking strategies hold the potential to transform the treatment of diabetic wounds, accelerating the healing process and enhancing patient outcomes.

Colloidal photonic crystals towards biological applications

Colloidal photonic crystals (CPCs), fabricated from the assembly of micro-/nano-particles, have attracted considerable interest due to their unique properties, such as structural color, slow-photon effect, and high specific surface area (SSA). Benefiting from these properties, significant progress has been made in the biological applications of CPCs. In this perspective, these properties and relative manipulation strategies are firstly discussed, building bridges between properties and biological applications of CPCs. Structural color endows CPCs with naked-eye sensing capability, which can be applied to physiological state assessment and diagnosis, as well as self-report of CPC-based diagnostic and therapeutic devices. The slow-photon effect contributes to enhanced fluorescence, surface-enhanced Raman scattering, and efficacy of photodynamic/photothermal therapy, when CPCs are combined with corresponding functional materials. High SSA provides CPCs with abundant binding sites and superior capabilities for loading, adsorption, delivery, etc. These properties can be utilized individually or synergistically to grant CPCs superior performance in biological applications. Next, the recent advancements of CPCs towards biological applications are summarized, including biosensors, wound dressings, cells-on-a-chip, and phototherapy. Finally, a perspective on the challenges and future development of CPCs for biological applications is presented.

Photothermal responsive porous hollow microneedles as Chinese medicine versatile delivery system for wound healing

Chinese medicine is identified as a candidate for wound healing. Attempts in this field tend to develop efficient dosage forms for delivering Chinese medicine with low side effects. In this paper, we proposed novel photothermal responsive porous hollow microneedles (PRPH-MNs) as a versatile Chinese medicine delivery system for efficient antibacterial wound treatment. The PRPH-MNs are composed of porous resin shells with good mechanical property, hydrogel cores, and a photothermal graphene oxide hybrid substrate. The hollow structure provides sufficient space for loading the drug dispersed hydrogel, while the porous resin shells could not only block the direct contact between drugs and wound sites but also provide channels for facilitating the drug release from the core. In addition, benefiting from the photothermal effect of their substrate, the PRPH-MNs could be heated under near-infrared (NIR) irradiation for controllable promotion of drug release. Based on these features, we have proved that the antibacterial Chinese medicine Rhein loaded PRPH-MNs were effective in promoting wound healing due to their good antibacterial property and on-demand drug release. Thus, we believe that the proposed PRPH-MNs are valuable for delivery of different drugs for clinical applications.

Decellularized Tumor Tissues Integrated with Polydopamine for Wound Healing

Natural biomaterials have been showing extensive potential in wound healing; attempts therefore focus on productions achieving both antimicrobial and tissue regenerative abilities. Here, we construct a decellularized human colon tumor (DHCT)-derived scaffold for wound remolding via microfluidic bioprinting. The DHCT retains a series of growth factors, fibrin, and the collagen configuration, that favor tissue repair and reconstruction. Specifically, the scaffold shows superior abilities in cell migration and angiogenesis. The biocompatible scaffold is also imparted with tissue adhesion ability and photothermal effect due to the coating of biologically derived polydopamine on the surface. The strong photothermal effect under near-infrared irradiation also present the scaffold with an antibacterial rate exceeding 90%. Furthermore, in vivo experiments convinced that the polydopamine-integrated DHCT scaffold can markedly expedite the healing process of acute extensive wounds. These findings indicate that composite materials derived from natural tumors have substantial potential in pertinent clinical applications.

Stem Cell-Derived Nanovesicles Embedded in Dual-Layered Hydrogel for Programmed ROS Regulation and Comprehensive Tissue Regeneration in Burn Wound Healing

Burn wounds often bring high risks of delayed healing process and even death. Reactive oxygen species (ROS) play a crucial role in burn wound repair. However, the dynamic process in wound healing requires both the generation of ROS to inhibit bacteria and the subsequent reduction of ROS levels to initiate and promote tissue regeneration, which calls for a more intelligent ROS regulation dressing system. Hence, a dual-layered hydrogel (Dual-Gel) tailored to the process of burn wound repair is designed: the inner layer hydrogel (Gel 2) first responds to bacterial hyaluronidase (Hyal) to deliver aggregation-induced emission photosensitizer functionalized adipose-derived stem cell nanovesicles, which generate ROS upon light irradiation to eliminate bacteria; then the outer layer hydrogel (Gel 1) continuously starts a long-lasting consumption of excess ROS at the wound site to accelerate tissue regeneration. Simultaneously, the stem cell nanovesicles trapped in the burns wound also provide nutrients and mobilize neighboring tissues to thoroughly assist in inflammation regulation, cell proliferation, migration, and angiogenesis. In summary, this study develops an intelligent treatment approach on burn wounds by programmatically regulating ROS and facilitating comprehensive wound tissue repair.

A comprehensive exploration of hydrogel applications in multi-stage skin wound healing

Hydrogels, as an emerging biomaterial, have found extensive use in the healing of wounds due to their distinctive physicochemical structure and functional properties. Moreover, hydrogels can be made to match a range of therapeutic requirements for materials used in wound healing through specific functional modifications. This review provides a step-by-step explanation of the processes involved in cutaneous wound healing, including hemostasis, inflammation, proliferation, and reconstitution, along with an investigation of the factors that impact these processes. Furthermore, a thorough analysis is conducted on the various stages of the wound healing process at which functional hydrogels are implemented, including hemostasis, anti-infection measures, encouraging regeneration, scar reduction, and wound monitoring. Next, the latest progress of multifunctional hydrogels for wound healing and the methods to achieve these functions are discussed in depth and categorized for elucidation. Finally, perspectives and challenges associated with the clinical applications of multifunctional hydrogels are discussed.

Self-Healing Dynamic Hydrogel Microparticles with Structural Color for Wound Management

Chronic diabetic wounds confront a significant medical challenge because of increasing prevalence and difficult-healing circumstances. It is vital to develop multifunctional hydrogel dressings, with well-designed morphology and structure to enhance flexibility and effectiveness in wound management. To achieve these, we propose a self-healing hydrogel dressing based on structural color microspheres for wound management. The microsphere comprised a photothermal-responsive inverse opal framework, which was constructed by hyaluronic acid methacryloyl, silk fibroin methacryloyl and black phosphorus quantum dots (BPQDs), and was further re-filled with a dynamic hydrogel. The dynamic hydrogel filler was formed by Knoevenagel condensation reaction between cyanoacetate and benzaldehyde-functionalized dextran (DEX-CA and DEX-BA). Notably, the composite microspheres can be applied arbitrarily, and they can adhere together upon near-infrared irradiation by leveraging the BPQDs-mediated photothermal effect and the thermoreversible stiffness change of dynamic hydrogel. Additionally, eumenitin and vascular endothelial growth factor were co-loaded in the microspheres and their release behavior can be regulated by the same mechanism. Moreover, effective monitoring of the drug release process can be achieved through visual color variations. The microsphere system has demonstrated desired capabilities of controllable drug release and efficient wound management. These characteristics suggest broad prospects for the proposed composite microspheres in clinical applications.

Engineered Microorganisms for Advancing Tumor Therapy

Engineered microorganisms have attracted significant interest as a unique therapeutic platform in tumor treatment. Compared with conventional cancer treatment strategies, engineering microorganism-based systems provide various distinct advantages, such as the intrinsic capability in targeting tumors, their inherent immunogenicity, in situ production of antitumor agents, and multiple synergistic functions to fight against tumors. Herein, the design, preparation, and application of the engineered microorganisms for advanced tumor therapy are thoroughly reviewed. This review presents a comprehensive survey of innovative tumor therapeutic strategies based on a series of representative engineered microorganisms, including bacteria, viruses, microalgae, and fungi. Specifically, it offers extensive analyses of the design principles, engineering strategies, and tumor therapeutic mechanisms, as well as the advantages and limitations of different engineered microorganism-based systems. Finally, the current challenges and future research prospects in this field, which can inspire new ideas for the design of creative tumor therapy paradigms utilizing engineered microorganisms and facilitate their clinical applications, are discussed.

A bismuth-based double-network hydrogel-mediated synergistic photothermal-chemodynamic therapy for accelerated wound healing

Multidrug-resistant bacterial infections present a significant challenge to wound healing. Non-antibiotic approaches such as photothermal therapy (PTT) and chemodynamic therapy (CDT) are promising but have suboptimal anti-bacterial efficacy. Herein, we developed a green bismuth-based double-network hydrogel (Bi@P-Cu) as a PTT/CDT synergistic platform for accelerated drug-resistant bacteria-infected wound healing. Bismuth (Bi) nanoparticles fabricated using a microwave method were used as a highly efficient and biocompatible PTT agent while the integration of a small amount of CDT agent Cu2+ endowed the hydrogel with excellent mechanical and self-healing properties, markedly increased photothermal efficiency, promoted cell migration ability, and negligible toxicity. Importantly, PTT enhanced the production of hydroxyl radicals in CDT and the destruction of bacterial cell membranes, which in turn enhanced the thermal sensitivity of bacteria. This synergistic anti-bacterial effect, together with the demonstrated capability to promote angiogenesis and anti-inflammation as well as enhanced fibroblast proliferation, led to accelerated wound healing in a full-thickness mouse model of resistant bacterial infection. This study provides an effective and safe strategy to eliminate drug-resistant bacteria and accelerate wound healing through green, non-antibiotic, double-network hydrogel-mediated synergistic PTT and CDT.

Genetically Edited Cascade Nanozymes for Cancer Immunotherapy

Immune checkpoint blockade (ICB) has brought tremendous clinical progress, but its therapeutic outcome can be limited due to insufficient activation of dendritic cells (DCs) and insufficient infiltration of cytotoxic T lymphocytes (CTLs). Evoking immunogenic cell death (ICD) is one promising strategy to promote DC maturation and elicit T-cell immunity, whereas low levels of ICD induction of solid tumors restrict durable antitumor efficacy. Herein, we report a genetically edited cell membrane-coated cascade nanozyme (gCM@MnAu) for enhanced cancer immunotherapy by inducing ICD and activating the stimulator of the interferon genes (STING) pathway. In the tumor microenvironment (TME), the gCM@MnAu initiates a cascade reaction and generates abundant cytotoxic hydroxyl (•OH), resulting in improved chemodynamic therapy (CDT) and boosted ICD activation. In addition, released Mn2+ during the cascade reaction activates the STING pathway and further promotes the DC maturation. More importantly, activated immunogenicity in the TME significantly improves gCM-mediated PD-1/PD-L1 checkpoint blockade therapy by eliciting systemic antitumor responses. In breast cancer subcutaneous and lung metastasis models, the gCM@MnAu showed synergistically enhanced therapeutic effects and significantly prolonged the survival of mice. This work develops a genetically edited nanozyme-based therapeutic strategy to improve DC-mediated cross-priming of T cells against poorly immunogenic solid tumors.

Stimuli‐Responsive Hydrogels for Antibacterial Applications

Hydrogels have emerged as promising candidates for biomedical applications, especially in the field of antibacterial therapeutics, due to their unique structural properties, highly tunable physicochemical properties, and excellent biocompatibility. The integration of stimuli-responsive functions into antibacterial hydrogels holds the potential to enhance their antibacterial properties and therapeutic efficacy, dynamically responding to different external or internal stimuli, such as pH, temperature, enzymes, and light. Therefore, this review describes the applications of hydrogel dressings responsive to different stimuli in antibacterial therapy. The collaborative interaction between stimuli-responsive hydrogels and antibacterial materials is discussed. This synergistic approach, in contrast to conventional antibacterial materials, not only amplifies the antibacterial effect but also alleviates adverse side effects and diminishes the incidence of multiple infections and drug resistance. The review provides a comprehensive overview of the current challenges and outlines future research directions for stimuli-responsive antibacterial hydrogels. It underscores the imperative for ongoing interdisciplinary research aimed at unraveling the mechanisms of wound healing. This understanding is crucial for optimizing the design and implementation of stimuli-responsive antibacterial hydrogels. Ultimately, this review aims to offer scientific guidance for the development and practical clinical application of stimuli-responsive antibacterial hydrogel dressings.

Preparation and Application of Hemostatic Hydrogels

Hemorrhage remains a critical challenge in various medical settings, necessitating the development of advanced hemostatic materials. Hemostatic hydrogels have emerged as promising solutions to address uncontrolled bleeding due to their unique properties, including biocompatibility, tunable physical characteristics, and exceptional hemostatic capabilities. In this review, a comprehensive overview of the preparation and biomedical applications of hemostatic hydrogels is provided. Particularly, hemostatic hydrogels with various materials and forms are introduced. Additionally, the applications of hemostatic hydrogels in trauma management, surgical procedures, wound care, etc. are summarized. Finally, the limitations and future prospects of hemostatic hydrogels are discussed and evaluated. This review aims to highlight the biomedical applications of hydrogels in hemorrhage management and offer insights into the development of clinically relevant hemostatic materials.

Enzymatic interfacial conversion of acylglycerols in Pickering emulsions stabilized by hydrogel microparticles

HYPOTHESIS

A critical challenge in the enzymatic conversion of acylglycerols is the limited exposure of the enzyme dissolved in the aqueous solution to the hydrophobic substrate in the oil phase. Positioning the enzyme in a microenvironment with balanced hydrophobicity and hydrophilicity in Pickering emulsion will facilitate the acylglycerol-catalyzing reactions at the interface between the oil and liquid phases.

EXPERIMENTS

In this work, to overcome the challenge of biphasic catalysis, we report a method to immobilize enzymes in polyethylene glycol (PEG)-based hydrogel microparticles (HMPs) at the interface between the oil and water phases in Pickering emulsion to promote the enzymatic conversion of acylglycerols.

FINDINGS

3 wt% of HMPs can stabilize the oil-in-water Pickering emulsion for at least 14 days and increase the viscosity of emulsions. Lipase-HMP conjugates showed significantly higher hydrolytic activity in Pickering emulsion; HMP-immobilized lipase SMG1 showed an activity about three times that of free lipase SMG1. Co-immobilization of a lipase and a fatty acid photodecarboxylase from Chlorella variabilis (CvFAP) in Pickering emulsion enables light-driven cascade conversion of triacylglycerols to hydrocarbons, transforming waste oil to renewable biofuels in a green and sustainable approach. HMPs stabilize the Pickering emulsion and promote interfacial biocatalysis in converting acylglycerols to renewable biofuels.

Seconds Timescale Synthesis of Highly Stretchable Antibacterial Hydrogel for Skin Wound Closure and Epidermal Strain Sensor

Effective wound healing is critical for patient care, and the development of novel wound dressing materials that promote healing, prevent infection, and are user-friendly is of great importance, particularly in the context of point-of-care testing (POCT). This study reports the synthesis of a hydrogel material that can be produced in less than 10 s and possesses antibacterial activity against both gram-negative and gram-positive microorganisms, as well as the ability to inhibit the growth of eukaryotic cells, such as yeast. The hydrogel is formed wholly based on covalent-like hydrogen bonding interactions and exhibits excellent mechanical properties, with the ability to stretch up to more than 600% of its initial length. Furthermore, the hydrogel demonstrates ultra-fast self-healing properties, with fractures capable of being repaired within 10 s. This hydrogel can promote skin wound healing, with the added advantage of functioning as a strain sensor that generates an electrical signal in response to physical deformation. The strain sensor composed of a rubber shell realizes fast and responsive strain sensing. The findings suggest that this hydrogel has promising applications in the field of POCT for wound care, providing a new avenue for improved patient outcomes.

Developing conductive hydrogels for biomedical applications

Conductive hydrogels have attracted copious attention owing to their grateful performances, such as similarity to biological tissues, compliance, conductivity and biocompatibility. A diversity of conductive hydrogels have been developed and showed versatile potentials in biomedical applications. In this review, we highlight the recent advances in conductive hydrogels, involving the various types and functionalities of conductive hydrogels as well as their applications in biomedical fields. Furthermore, the current challenges and the reasonable outlook of conductive hydrogels are also given. It is expected that this review will provide potential guidance for the advancement of next-generation conductive hydrogels.

Recent advances of hydrogels as smart dressings for diabetic wounds

Chronic diabetic wounds have been an urgent clinical problem, and wound dressings play an important role in their management. Due to the design of traditional dressings, it is difficult to achieve adaptive adhesion and on-demand removal of complex diabetic wounds, real-time monitoring of wound status, and dynamic adjustment of drug release behavior according to the wound microenvironment. Smart hydrogels, as smart dressings, can respond to environmental stimuli and achieve more precise local treatment. Here, we review the latest progress of smart hydrogels in wound bandaging, dynamic monitoring, and drug delivery for treatment of diabetic wounds. It is worth noting that we have summarized the most important properties of smart hydrogels for diabetic wound healing. In addition, we discuss the unresolved challenges and future prospects in this field. We hope that this review will contribute to furthering progress on smart hydrogels as improved dressing for diabetic wound healing and practical clinical application.

Copper incorporated biomaterial-based technologies for multifunctional wound repair

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

Designing Bioorthogonal Reactions for Biomedical Applications

Bioorthogonal reactions are a class of chemical reactions that can be carried out in living organisms without interfering with other reactions, possessing high yield, high selectivity, and high efficiency. Since the first proposal of the conception by Professor Carolyn Bertozzi in 2003, bioorthogonal chemistry has attracted great attention and has been quickly developed. As an important chemical biology tool, bioorthogonal reactions have been applied broadly in biomedicine, including bio-labeling, nucleic acid functionalization, drug discovery, drug activation, synthesis of antibody-drug conjugates, and proteolysis-targeting chimeras. Given this, we summarized the basic knowledge, development history, research status, and prospects of bioorthogonal reactions and their biomedical applications. The main purpose of this paper is to furnish an overview of the intriguing bioorthogonal reactions in a variety of biomedical applications and to provide guidance for the design of novel reactions to enrich bioorthogonal chemistry toolkits.

Controllably Self-Assembled Antibacterial Nanofibrils Based on Insect Cuticle Protein for Infectious Wound Healing

Developing self-assembled biomedical materials based on insect proteins is highly desirable due to their advantages of green, rich, and sustainable characters as well as excellent biocompatibility, which has been rarely explored. Herein, salt-induced controllable self-assembly, antibacterial performance, and infectious wound healing performance of an insect cuticle protein (OfCPH-2) originating from the Ostrinia furnacalis larva head capsule are investigated. Interestingly, the addition of salts could trigger the formation of beaded nanofibrils with uniform diameter, whose length highly depends on the salt concentration. Surprisingly, the OfCPH-2 nanofibrils not only could form functional films with broad-spectrum antibacterial abilities but also could promote infectious wound healing. More importantly, a possible wound healing mechanism was proposed, and it is the strong abilities of OfCPH-2 nanofibrils in promoting vascular formation and antibacterial activity that facilitate the process of infectious wound healing. Our exciting findings put forward instructive thoughts for developing innovative bioinspired materials based on insect proteins for wound healing and related biomedical fields.

Smart Responsive and Controlled-Release Hydrogels for Chronic Wound Treatment

Chronic wounds are a major health challenge that require new treatment strategies. Hydrogels are promising drug delivery systems for chronic wound healing because of their biocompatibility, hydration, and flexibility. However, conventional hydrogels cannot adapt to the dynamic and complex wound environment, which involves low pH, high levels of reactive oxygen species, and specific enzyme expression. Therefore, smart responsive hydrogels that can sense and respond to these stimuli are needed. Crucially, smart responsive hydrogels can modulate drug release and eliminate pathological factors by changing their properties or structures in response to internal or external stimuli, such as pH, enzymes, light, and electricity. These stimuli can also be used to trigger antibacterial responses, angiogenesis, and cell proliferation to enhance wound healing. In this review, we introduce the synthesis and principles of smart responsive hydrogels, describe their design and applications for chronic wound healing, and discuss their future development directions. We hope that this review will inspire the development of smart responsive hydrogels for chronic wound healing.

Functional Covalent Organic Framework (COF) Nanoparticles for Biomimic Mineralization and Bacteria Inhabitation

Biomimic mineralization of hard tissues with hierarchical structures is a challenging task, while designing multifunctional materials possessing both the ability of biomimic mineralization and drug delivery is even more difficult. Herein, inspired by the multilevel structure and mineralization ability of amelogenin, a novel carboxyl-functionalized covalent organic framework (COF) nanosphere material was designed and synthesized, which exhibited a significant biomimetic remineralization ability as demonstrated on SiO2 glass, Ti6Al4V, and an acid-etched enamel surface. Furthermore, the nanoporous structure also enables the COF nanospheres to serve as a drug delivery system for the controlled release of antibacterial drugs. This work provides a promising strategy for the design of multifunctional biomimic materials.

Chitosan Hydrogel-Delivered ABE8e Corrects PAX9 Mutant in Dental Pulp Stem Cells

Hypodontia (dental agenesis) is a genetic disorder, and it has been identified that the mutation C175T in PAX9 could lead to hypodontia. Cas9 nickase (nCas9)-mediated homology-directed repair (HDR) and base editing were used for the correction of this mutated point. This study aimed to investigate the effect of HDR and the base editor ABE8e in editing PAX9 mutant. It was found that the chitosan hydrogel was efficient in delivering naked DNA into dental pulp stem cells (DPSCs). To explore the influence of the C175T mutation in PAX9 on the proliferation of DPSCs, hydrogel was employed to deliver PAX9 mutant vector into DPSCs, finding that the PAX9-containing C175T mutation failed to promote the proliferation of DPSCs. Firstly, DPSCs stably carrying PAX9 mutant were constructed. Either an HDR or ABE8e system was delivered into the above-mentioned stable DPSCs, and then the correction efficiency using Sanger sequencing and Western blotting was determined. Meanwhile, the ABE8e presented significantly higher efficiency in correcting C175T compared with HDR. Furthermore, the corrected PAX9 presented enhanced viability and differentiation capacity for osteogenic and neurogenic lineages; the corrected PAX9 even possessed extremely enhanced transcriptional activation ability. In summary, this study has powerful implications for studies into base editors, chitosan hydrogel, and DPSCs in treating hypodontia.