Preparation of Photocatalytic and Antibacterial MOF Nanozyme Used for Infected Diabetic Wound Healing

Bacterial membrane-anchored lipopeptide/MXene nanoplatform for tri-modal therapy toward bacteria-infected diabetic wound

Diabetic wound healing is extremely difficult, originating from the aspects of bacterial infection, continuous inflammation, hypoxia and excessive reactive oxygen species (ROS), etc. Consequently, multifunctional nanoplatforms capable of highly eliminating bacteria, scavenging ROS and promoting angiogenesis possess a promising prospect. This work reports our fabrication of lipopeptide/Ti3C2Tx MXene nanohybrid to cure bacteria-infected diabetic wounds. Ti3C2Tx nanosheet has been employed to disrupt the bacterial membrane through both the physical puncture mediated by direct contact and mild-temperature photothermal therapy (PTT) due to its excellent photothermal conversion efficiency. Moreover, it exhibits the capacities of ROS scavenging and pro-angiogenesis during the diabetic wound healing process. Positively charged lipopeptide integration on 2D Ti3C2Tx MXene improves the contact of Ti3C2Tx nanosheet with negative bacterial membrane for membrane-anchoring. More importantly, drug-free lipopeptide shows antibacterial capacity, which compensates the decline in therapeutic efficacy of mild-temperature PTT because of its inferior heat intensity. The cooperation between 2D Ti3C2Tx MXene and therapeutic lipopeptide allows for the effective cure on bacteria-infected diabetic wound.

Hydrophobic carbon/bamboo-like carbon nanotube supported Fe/Co nanocomposites with antibacterial activity for wound healing

The development of novel nanozymes with excellent enzyme simulation ability provides a new perspective for antibacterial and wound healing. However, the enzyme activity of traditional simplex nanozyme is not sufficient, meanwhile the nanozymic catalytic therapy alone cannot fulfill the purpose of effective antibacterial and wound healing. Hence, we develop novel multifunctional nanocomposites composed of FeCo alloys integrate with carbon spheres and carbon nanotubes (FeCo-C/CNT NCs) with hydrophobic property, enhanced oxidase-like (OXD-like) activity and photothermal property. Remarkably, in vitro experiment shows the antibacterial rates of 200 μg/mL FeCo-C/CNT NCs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) are as high as 83.46 % and 90.98 %, respectively. The mechanism of synergistic antibacterial effect is not only due to the reactive oxygen species (ROS) generation from FeCo alloy part of FeCo-C/CNT NCs, but also because the local high temperature generated by the photothermal effects of FeCo-C/CNT NCs under near infrared (NIR) laser irradiation, as well as heat promoted ROS production. The FeCo-C/CNT NCs under NIR laser irradiation present best wound healing via hydrophobic protection, synergistic catalytic and photothermal therapy on S. aureus-infected mice. This work introduces a novel alloy nanozyme with excellent antibacterial property, providing new idea in the field of wound healing.

Precision delivery of pretreated macrophage-membrane-coated Pt nanoclusters for improving Alzheimer's disease-like cognitive dysfunction induced by Porphyromonas gingivalis

Oral infection with Porphyromonas gingivalis (P. gingivalis), a kind of pathogenic bacteria causing periodontitis, can increase the risk of Alzheimer's disease (AD) and cause cognitive decline. Therefore, precise intracerebral antimicrobial therapy to reduce the load of P. gingivalis in brain may serve as a potential therapeutic approach to improve AD-like cognitive impairment. A kind of nano-delivery system precisely targets bacteria in the brain through coating P. gingivalis stimulated macrophage membrane onto the surface of platinum nanoclusters (Pg-M-PtNCs). Approximate 50 nm spherical Pg-M-PtNCs demonstrate good biocompatibility and the pretreated macrophage membranes can inhibit macrophages phagocytosis and increase the adherence to bacteria. Pg-M-PtNCs can significantly inhibit the growth of P.gingivalis in vitro, and are effectively delivered and remain at the infection site in the mice brain to reduce the bacterial load and neuronal damage, and then improve the AD-like cognitive dysfunction in the chronic periodontitis mice. Platinum nanoclusters coated with P. gingivalis pretreated macrophage membrane play an important role in targeting bacteria in the brain, and effectively improve AD-like cognitive function disorder caused by P. gingivalis infection in the brain.

Metal-organic frameworks-molecularly imprinted polymers (MOF-MIP): Synthesis, properties, and applications in detection and control of microorganisms

Microbial contamination poses a significant threat to human health, food safety, and the ecological environment. Its rapid spread and potential pathogenicity create an urgent global challenge for efficient detection and control. However, existing methods have several shortcomings such as traditional techniques like culture methods and polymerase chain reaction (PCR) are time-consuming, while nanomaterials and aptamers often lack selectivity, stability, and affordability. Additionally, conventional disinfectants can be inefficient, lead to drug resistance, and harm the environment. To address these challenges, developing new materials and technologies that are efficient, sensitive, and stable is crucial for microbial detection and control. In this context, metal-organic frameworks (MOF) and molecularly imprinted polymers (MIP) have emerged as promising functional materials due to their unique structural advantages. The high porosity of MOF provides ample imprinting sites for MIP, while MIP enhance selective adsorption and inactivation of target microorganisms by MOF. This synergistic combination results in a composite material that offers a novel solution for microbial detection, significantly improving sensitivity, selectivity, antibacterial efficiency, and environmental friendliness. This paper reviews the synthesis strategies of metal-organic frameworks-molecularly imprinted polymers (MOF-MIP), highlighting their structural properties and innovative applications in microbial detection, which aim to inspire researchers in related fields. Looking ahead, future advancements in material science and biotechnology are expected to lead to widespread use of MOF-MIP composites in food safety, environmental monitoring, medical diagnosis, and public health-providing robust support against microbial pollution. By studying the collaborative mechanisms of MOF and MIP while optimizing design processes will enhance precision speed cost-effectiveness in microbial detection technology significantly contributing to human health and environmental safety.

A multifunctional trap-capture-kill antibacterial system for enhanced wound healing via modified decellularized mushroom aerogels

Wound infections are prevalent and can result in prolonged healing times. In this study, we referred to the "trap-capture-kill" antibacterial strategy to create a wound dressing (DS/PDA@GO-L) by coupling graphene oxide (GO) with lysine and coating it onto the decellularized mushroom stem (DS) using polydopamine (PDA). The mechanism of action of the bacteria-killing process involves lysine chemotaxis and the siphoning effect of DS aerogel, with the process of killing the bacteria being initiated via near-infrared photothermal treatment. In vitro studies demonstrated that DS/PDA@GO-L exhibited excellent blood and cell compatibility, while in vivo experiments revealed its remarkable efficacy in combating bacterial infections. Specifically, the combination of DS/PDA@GO-L with photothermal therapy led to the elimination of over 95 % of S. aureus, E. coli, and Pseudomonas aeruginosa. Furthermore, the aerogel, when used in conjunction with photothermal therapy, significantly reduced bacterial infection at the wound site and accelerated wound healing. During the wound's proliferative phase, it notably enhanced vascularization and extracellular matrix deposition. Furthermore, immunohistochemical staining revealed that bacterial clearance led to a reduction in pro-inflammatory responses and a decrease in the expression of pro-inflammatory cytokines, thereby restoring the wound's inflammatory environment to a pro-regenerative state. Taken together, the developed DS/PDA@GO-L holds great potential in the field of infected skin wound healing.

A Self-Assembled Nanoreactor for Realizing Antibacterial Photodynamic/Gas Therapy and Promoting Wound Healing

Among various treatments employed to solve the global problem of bacterial infection, photodynamic therapy (PDT) is recognized as a method with great potential to inactivate a wide range of bacteria without the development of drug resistance. However, many commonly used photosensitizers (PSs) have the disadvantages of poor water-solubility and potential toxicity, which limits their clinical application. Additionally, nitric oxide (NO) has unique advantages in antibacterial treatments due to its small molecular weight. Herein, protoporphyrin IX (PpIX), L-arginine (L-Arg), and glycol chitosan (GC) are used to construct a self-assembled cationic Arg-GC-PpIX nanoreactor for efficient bacterial inactivation under white light illumination. The Arg-GC-PpIX nanoreactor with excellent water dispersity and stability can rapidly bind to bacteria through electrostatic interaction and produce local singlet oxygen (1O2)/NO under light irradiation, leading to a high antibacterial efficiency toward both Gram-negative and Gram-positive bacteria. Besides, these NPs also possess a desirable antibiofilm ability. Finally, Arg-GC-PpIX@Gel which is obtained through loading Arg-GC-PpIX into the sodium alginate (SA)/Ca2+ hydrogel shows a satisfactory ability to promote infected wound healing when combined with white light irradiation. Therefore, the rationally designed Arg-GC-PpIX nanoreactor with light-triggered 1O2/NO release is a promising antibacterial agent for achieving effective PDT/NO gas therapy.

Preparation of Au-modified metal organic framework nanozyme with tunable catalytic activity used for diabetic wound healing

Nanozymes with tunable catalytic activity have attracted attention in the field of biomedicine. Bacterial infections are the main causes of delayed or chronic wound healing. Therefore, antibacterial nanoplatforms with tunable enzymatic activity are urgently required for diabetic wound healing. Here, we propose a strategy for constructing Au-cluster-modified Prussian blue (PB) nanospheres (PB-Au) as antibacterial nanoplatforms for diabetic wound healing. The obtained PB-Au exhibited tunable peroxidase (POD)-like activity and maintained both photostability and catalytic stability. These advantages enhanced the antibacterial ability of the PB-Au enzyme. The results show that the bacterial biofilm disruption rate of the PB-Au enzyme was approximately 86 %. The bacterial elimination rate exceeded 95 %. Western blot (WB) data indicated that the expression of vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (CD31) was upregulated by PB-Au by approximately 1.3- and 1.4-fold, respectively. The WB results also suggested that PB-Au could promote angiogenesis. Animal experiments showed that PB-Au rapidly increased the temperature at the wound site by up to 52.6 ℃, which was beneficial for sterilization. The wound healing rate was approximately 98 %. The results demonstrate that PB-Au nanozymes with tunable peroxidase (POD)-like activities have great potential to accelerate diabetic wound healing.

Enhancing the performance of injectable self-activating PVA-alginate hydrogel by Ag@MXene nanozyme as NIR responsive and photoenhanced antibacterial platform for wound healing

Design of tough and functional hydrogel based on carbohydrate polymers is always attracting. Injectable hydrogel based on polyvinyl alcohol (PVA) and sodium alginate (Alg) have great potential for wound repair. However, simple hydrogel lacks functionality, such as antibacterial, which limits its application. Herein, we proposed a strategy of using Ag@MXene nanozyme to functionalize hydrogel and construct a near-infrared laser (NIR) responsive, reactive oxygen species (ROS) generating, and antibacterial platform for wound repair. Epigallocatechin gallate (EGCG) and Ag cluster modified Ti3C2 (E-Ag@Ti3C2) was prepared to enhance the performance of injectable PVA-alginate hydrogel (E-Ag@Ti3C2@H). The functionalized hydrogel presents porous structures (67 % porosity percentage) and excellent compressive and tensile properties (elongation up to 157 %). Under NIR laser irradiation, E-Ag@Ti3C2@H showed photothermal conversion efficiency and ROS generation ability. The inhibition rate for Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) can reach to 91.2 % and 90.3 %, respectively. Molecular biology experiments showed that the composite hydrogel could promote angiogenesis and wound healing by upregulating the expression of anti-inflammatory factors. The obtained injectable E-Ag@Ti3C2@H hydrogel is potential in accelerating diabetic wound healing.

Engineering ultrasmall gold nanoclusters: tailored optical modulation for phototherapeutic and multimodal biomedical applications

Ultrasmall gold nanoclusters (Au NCs) with core sizes below 2 nm exhibit distinctive physicochemical properties and hold remarkable promise in a variety of biomedical applications. Through precise synthesis and surface engineering, Au NCs can be endowed with high quantum yields, excellent stability, and favorable biocompatibility. Recent studies have demonstrated the versatility of Au NCs in imaging modalities-ranging from fluorescence and Raman to photoacoustics-as well as in light-driven therapeutics such as photodynamic therapy (PDT) and photothermal therapy (PTT). This review provides an overview of Au NC design strategies, highlighting ligand-assisted synthesis and supramolecular self-assembly for optimizing optical features and biological performance. Representative biomedical applications in optical imaging, biosensing, and phototherapy are summarized to illustrate the multifaceted benefits of Au NCs in disease diagnosis and treatment. Finally, challenges related to large-scale production, long-term biosafety, and clinical translation are discussed, along with future perspectives on leveraging Au NCs for next-generation theranostic platforms.

Photo-responsive antibacterial metal organic frameworks

The misuse and overuse of antibiotics have caused the emergence of antibiotic-resistant bacteria, making bacterial infections more challenging. The increasing prevalence of multidrug-resistant pathogens has driven researchers to explore novel therapeutic strategies. Phototherapy strategies that utilize photo-responsive biomaterials for their antibacterial properties have gained widespread attention due to their capability of precisely controlling bacterial inactivation with minimal side effects. Despite their potential, photodynamic therapies suffer from phototoxicity and low efficiency of photosensitizers, while photothermal therapy risks overheating, which may harm healthy tissues, thus restricting its broader application. Metal organic frameworks (MOFs) have unique physicochemical properties, which provide a promising way to deal with these challenges. MOFs can function as reservoirs, loading and releasing antibacterial agents, such as antibiotics or metal ions, upon light illumination by virtue of their metastable coordination bonds. Their porous structures enable controlled drug release and encapsulation of photosensitizers. Furthermore, MOFs' tunable composition and pore structure allow for the light-triggered generation of heat and reactive oxygen species, enhancing their antibacterial effectiveness. By doping MOFs with functional materials, it is possible to achieve multi-mode antibacterial effects. In this review, we will outline recent advancements of photo-responsive antibacterial MOFs, categorize their underlying mechanisms of action and highlight their prospects in addressing bacterial resistance.

Polypyrrole modified hFGF2-oil bodies for postsurgical melanoma recurrence suppression and wound healing acceleration

Surgical treatment is the primary method for treating malignant melanoma at present. However, tumor recurrence after surgery and difficulty in wound healing remain significant challenges. This study designed and constructed a therapeutic wound dressing by loading polypyrrole (PPy) into human fibroblast growth factor 2 (hFGF2) covalently bonded camelina oil bodies (h-OB) to form Ph-OB. In a postoperative B16F10 melanoma model in C57BL/6 mice, the photothermal properties of PPy were utilized to increase the temperature at the surgical wound site through near-infrared light irradiation, performing photothermal therapy to kill residual tumors and inhibit tumor recurrence. Meanwhile, the release of hFGF2 from the Ph-OB acts on the postoperative wound site, promotes fibroblast proliferation and migration to accelerate wound healing. In summary, the developed Ph-OB not only prevents tumor recurrence but also facilitates the healing of surgery-induced wounds, showing great potential in postoperative cancer treatment.

AuCu@CuO2 Aerogels with H2O2/O2 Self-Supplying and Quadruple Enzyme-Like Activity for MRSA-Infected Diabetic Wound Management

Diabetic wound healing presents serious clinical challenges due to the unique wound microenvironment characterized by hyperglycemia, bacterial infection, excessive oxidative stress, and hypoxia. Herein, a copper peroxide (CuO2)-coated AuCu bimetallic aerogel is developed that exhibits quadruple enzyme-mimicking activity and H2O2/O2 self-supplying to modulate the complex microenvironment of methicillin-resistant staphylococcus aureus (MRSA)-infected diabetic wounds. The AuCu@CuO2 aerogels demonstrate favorable photothermal properties and mimic four enzyme-like activities: peroxidase-like activity for producing toxic reactive oxygen species; catalase-like activity for decomposing H2O2 to release O2 to relieve oxidative stress and hypoxia; glucose oxidase-like activity for reducing excessive blood glucose and glutathione peroxidase-like activity for balancing abnormal glutathione level. The CuO2 coating facilitates a continuous and adequate in situ production of H2O2 within the mildly acidic infection microenvironment, enabling excellent antibacterial activity and reduced blood glucose levels during the initial treatment of infected diabetic wounds. Furthermore, the engineered AuCu@CuO2 aerogels not only scavenge elevated ROS during the inflammatory phase but also synergistically generate oxygen to promote wound healing. Overall, the AuCu@CuO2 aerogelsmicroenvironment can be activated by the diabetic wound infection microenvironments, alleviating inflammation, reducing hypoxia, lowering blood glucose levels, and enhancing angiogenesis and collagen fiber accumulation, thereby significantly improving diabetic wound healing.

A Targeted Core-Shell ZIF-8/Au@Fe3O4 Platform with Multiple Antibacterial Pathways for Infected Skin Wound Regeneration

Bacterial infections seriously retard skin wound healing. To enhance the antibacterial efficiency and subsequent skin regeneration, a core-shell structured therapeutic platform, named FZAM, was designed with multiple antimicrobial pathways. FZAM consists of nanosized Fe3O4 as the core and ZIF-8 loaded with Au nanoparticles (NPs) and maltodextrin as the shell. Fe3O4 and Au NPs form a heterojunction that generates hyperthermia and abundant reactive oxide species (ROS) under near-infrared (NIR) irradiation. This heterojunction also exhibits outstanding peroxidase-like activity. When bacteria invade, maltodextrin plays a targeting effect to increase the interaction between FZAM and bacteria, and with the synergistic action of NIR-induced hyperthermia and ROS as well as Zn2+ from ZIF-8, FZAM kills more than 99% of bacteria at 200 μg mL-1. Fortunately, FZAM is cytocompatible and even promotes the biofunctions of fibroblasts and endothelial cells. In infected skin wound models, FZAM sterilizes bacteria with NIR irradiation and subsequently reduces the inflammatory response and accelerates skin regeneration. This work provides a core-shell structured therapy platform for treating infection with the assistance of NIR irradiation and helping skin wound healing.

Nanozymes meet hydrogels: Fabrication, progressive applications, and perspectives

Nanozyme, a class of emerging enzyme mimics, is the nanomaterials with enzyme-mimicking activity, which has obtained significant and widespread applications in various fields. However, they still face many challenges in practical applications (e.g., instability and low biocompatibility in the physiological environments), which affect their widespread applications to a certain extent. Hydrogels with superior performances (e.g., the controllable degradability, good biocompatibility, hydrophilic properties, and adjustable physical properties) may provide a promising strategy to make up the existing deficiencies of nanozymes in practical applications. Thus, the sapiential combination of nanozymes with hydrogels endows nanozyme hydrogels with both characteristics of nanozymes and properties of hydrogels, making nanozyme hydrogels become novel multifunctional materials. In this review, we comprehensively summarizes the preparation, properties, and progressive applications of nanozyme hydrogels. First of all, the main design and preparation strategies of nanozyme hydrogels are considerately summarized. Then, the properties of different nanozyme hydrogels are introduced. In addition, sophisticated applications of nanozyme hydrogels in the fields of biosensing, biomedicine applications, and environmental are comprehensively summarized. Most importantly, future obstacles and chances in this emerging field are profoundly proposed. This review will provide a new horizon for the development and future applications of novel nanozyme hydrogels.

Stimuli-responsive dual-drug loaded microspheres with differential drug release for antibacterial and wound repair promotion

The healing of infected wounds is a complex and dynamic process requiring tailored treatment strategies that address both antimicrobial and reparative needs. Despite the development of numerous drugs, few approaches have been devised to optimize the timing of drug release for targeting distinct phases of infection control and tissue repair, limiting the overall treatment efficacy. Here, a stimuli-responsive microsphere encapsulating dual drugs was developed to facilitate differential drug release during distinct phases of antibacterial and repair promotion, thereby synergistically enhancing wound healing. Specifically, zeolite imidazolate backbone in poly (lactic-co-glycolic acid) (PLGA) microsphere was employed for the encapsulation of ciprofloxacin (CIP), responding to acidic environment of bacteria and releasing antibiotic for antibacterial therapy. Meanwhile, curcumin (CUR) encapsulated in PLGA exhibited a gradual release profile, contributing to synergistic antibacterial effects. During the tissue repair phase, near-infrared light stimulation of Fe3O4 embedded in PLGA generated heat, elevating the temperature to the glass transition point of PLGA, which significantly enhanced the release of CUR thereby promoting tissue repair. In vitro experiments demonstrated that the release of CIP and CUR achieved significant antibacterial effects in the early stages of treatment. Additionally, CUR could effectively enhance fibroblast migration and proliferation. In vivo studies using a mouse abscess model revealed that the microspheres exhibited remarkable antibacterial and wound-healing capabilities, effectively enhancing the re-epithelialization of wound tissue and reducing the infiltration of inflammatory cells. This study provides novel strategies for constructing drug delivery systems that match dynamic stages of wound healing, offering improved therapeutic outcomes for infected wounds.

Acid-Responsive Bacteria-Targeted Zinc-Porphyrin Based Sonosensitizer with Enhancing Antibacterial Efficacy and Biofilm Eradication for Infected Wounds Healing

Diseases caused by bacterial infections place a significant burden on global public health. Sonodynamic therapy (SDT), as an emerging antibacterial treatment, faces clinical challenges due to the non-polar nature of most sonosensitizers. To address this, an acid-responsive zinc-porphyrin-based sonosensitizer (Zn-TCPP) is developed via a simple thermal reaction, which is then coated with phenylboronic acid-modified hyaluronic acid (B-HA), to fabricate B-HA@Zn-TCPP. While in the mildly acidic microenvironment mimicking an infected wound site, the released B-HA@Zn-TCPP achieves effective SDT activity. The disruption of the bacterial membrane and the levels of intracellular reactive oxygen species (ROS) verified that the inhibition rate can reach 99% within 5 min, without any development of resistance after 15 consecutive generations of culture. Additionally, under ultrasound (US) -mediated cavitation, B-HA@Zn-TCPP exhibits excellent penetration into biofilms, achieving a 90.04% bactericidal rate for bacteria within biofilms. In vivo studies further demonstrated that B-HA@Zn-TCPP can effectively accelerate the healing of bacterial infected wounds with a wound healing rate of 98.65% within 9 days. Therefore, B-HA@Zn-TCPP as a novel sonosensitizer offers a viable strategy to overcome the limitations of traditional sonosensitizers for the bacterial wound infections.

Responsive hydrogel modulator with self-regulated polyphenol release for accelerating diabetic wound healing via precise immunoregulation

Nonhealing chronic wounds are intractable clinical complications of diabetes and are characterized by high protease activity, severe oxidative stress and sustained inflammatory response. In this case, the development of functional hydrogel dressings to modulate the immune microenvironment is a well-known strategy, where the precise stimuli-responsive and spatiotemporally controlled release of bioactive molecules remains a huge challenge. Herein, we developed responsive hydrogels with self-regulated bioactive molecule release based on the protease activity in diabetic wound sites, to serve as a smart immune microenvironment modulator for accelerating wound healing. The hydrogels were fabricated by grafting oxidized hyaluronic acid with epigallocatechin-3-gallate (EGCG) and gelatin methacryloyl (GelMA) under UV irradiation. Resveratrol nanoparticles were further loaded into the hydrogels before gelation to construct a polyphenol delivery system. The prepared hydrogels could achieve the on-demand release of polyphenol upon degradation by protease, as confirmed via degradation and polyphenol release experiments. The released polyphenol was demonstrated to have the capacity to effectively scavenge excessive free radicals, promote macrophage polarization, reduce proinflammatory factor (TNF-α) expression and augment anti-inflammatory factor (IL-10) expression in vitro. Additionally, in vivo rat wound healing model experiment results confirmed that these hydrogels promoted collagen deposition and granulation tissue regeneration, accelerating diabetic wound healing. Based on the protease-responsive degradation characteristic of the hydrogels and high protease activity in the diabetic wound microenvironment, hydrogels with exquisite polyphenol release controllability are promising candidates as dressings for diabetic wound management.

Quasi Fe MIL-53 nanozyme inducing ferroptosis and immunogenic cell death for cancer immunotherapy

Nanozymes offer diverse therapeutic potentials for cancer treatment which is dependent on the development of nanomaterials. Quasi-metal-organic framework is a class of metal-organic framework-derived nanomaterials with a transition state from metal-organic frameworks towards metal oxide featuring porous structure and high activity. Herein an iron-based quasi-metal-organic framework nanozyme Q-MIL-53(Fe) is reported via a controlled deligandation strategy, exhibiting enhanced peroxidase-/catalase-mimic activity and glutathione depletion capacity, whose underlying mechanisms are studied via density functional theory calculations. Q-MIL-53(Fe) demonstrates biocompatibility and superior antitumor efficacy compared to pristine MIL-53(Fe). It can activate antitumor immune response by inducing ferroptosis and immunogenic cell death, promoting dendritic cell maturation and T lymphocytes infiltration. Furthermore, a combination of Q-MIL-53(Fe) and programmed cell death protein 1 antibody amplifies cancer immunotherapy. This study validates the antitumor activity of quasi-metal-organic frameworks and its immunotherapy induction potential. It would broaden the application of quasi-metal-organic frameworks and open avenues for developing antitumor nanozymes.

Photosynthesis-Inspired NIR-Triggered Fe₃O₄@MoS₂ Core-Shell Nanozyme for Promoting MRSA-Infected Diabetic Wound Healing

Bacterial infections can lead to severe medical complications, including major medical incidents and even death, posing a significant challenge in clinical trauma repair. Consequently, the development of new, efficient, and non-resistant antimicrobial agents has become a priority for medical practitioners. In this study, a stepwise hydrothermal reaction strategy is utilized to prepare Fe3O4@MoS2 core-shell nanoparticles (NPs) with photosynthesis-like activity for the treatment of bacterial infections. The Fe3O4@MoS2 NPs continuously catalyze the production of reactive oxygen species (ROS) from hydrogen peroxide through photosynthesis-like reactions and convert light energy into heat with a photothermal efficiency of 30.30%. In addition, the photosynthetically generated ROS, combined with the iron-induced cell death mechanism of the Fe3O4@MoS2 NPs, confer them with exceptional and broad-spectrum antibacterial properties, achieving antimicrobial activities of up to 98.62% for Staphylococcus aureus, 99.22% for Escherichia coli, and 98.55% for methicillin-resistant Staphylococcus aureus. The composite exhibits good cell safety and hemocompatibility. Finally, a full-thickness diabetic wound model validates the significant pro-healing properties of Fe3O4@MoS2 in chronic diabetic wounds. Overall, the design of photosynthesis-inspired Fe3O4@MoS2 presents new perspectives for developing efficient photothermal nano-enzymatic compounds, offering a promising solution to the challenges of antimicrobial drug resistance and antibiotic misuse.

Solar radiation-promoted selective photocatalytic degradation of Congo red dye by a novel amorphous Cr-based metal-organic framework serving as sensor for 2,4,6-trinitrophenol explosive detection

Synthesis of novel benzene-1,2,4-tricarboxylic acid-based chromium metal-organic framework (designated as Cr-BTC MOF) by solvothermal method using water:ethanol:dimethylformamide (1:1:2) as solvent media has been undertaken with an aim to exploit its role as photocatalyst in degradation of some anionic dyes along with sensing potential of some explosives. The MOF has been characterized by Fourier transform infra-red, scanning electron microscopy, Brunauer-Emmett Teller and powder X-Ray diffraction techniques and has shown high thermal stability, upto 373 °C. The prepared MOF was utilized as photocatalyst in selective degradation of Congo red (CR) dye. The effects of pH, source of radiation, initiator and concentration of catalyst were monitored and the results have shown that catalyst exhibits maximum efficiency of 93.3% in the presence of sunlight in neutral medium. The stability and reusability of the catalyst, after four cycles of reusability, renders it to be a highly efficient photocatalyst in the treatment of wastewater under the effect of sunlight. Photoluminescence-detection of explosives viz. 2,4,6-trinitrophenol and nitromethane, has been carried out, wherein Stern-Volmer equation was used to assess the quenching efficiency evaluated. The results have shown exceptional efficiency and selectivity of Cr-BTC MOF towards detection of 2,4,6-trinitrophenol (94%). The reusability has shown the synthesized MOF to display excellent recyclability upto 5 cycles. Minimum inhibitory concentration (MIC) method was investigated to establish their antibacterial efficacy against some Gram-positive and Gram-negative strains. The MOF has showed good efficacy towards Bacillus cereus and Staphylococcus aureus, displaying a MIC value of 7.81 µg/mL, and Pseudomonas aeruginosa (15.625 µg/mL) similar to the standard antibacterial drug, chloramphenicol, thereby establishing their biological efficacy.

Glucose-Activated Janus Wound Dressing for Enhanced Management of Infected and Exudative Diabetic Wounds

Diabetic wounds, often multifactorial and affecting multiple organs, pose substantial challenges to patient well-being, drawing significant interest in biomedical engineering. The demanding wound microenvironment, marked by heightened glucose levels, local exudate, and bacterial infections, emphasizes the pressing demand for advanced wound dressings to meet escalating clinical needs. Herein, a Janus wound dressing with an integration of an antimicrobial hydrophobic nanofiber layer and a 3D hydrophilic sponge was designed and prepared to manage and utilize wound exudate. The hydrophobic layer skillfully combined electrospun poly(ε-caprolactone) (PCL) nanofiber membranes (ENMs) and metal-organic frameworks (MOFs) with peroxidase-like properties by solvent etching, and glucose oxidase (GOx) was grafted through ligand interaction. GOx acts to consume glucose while modulating pH, thus suitable pH and self-supplied H2O2 were able to activate the catalytic activity of MOFs to generate •OH. Additionally, hydrophilic 3D sponges are constructed using gas foaming technology, which are tactfully combined with hydrophobic ENMs to form a Janus structure, which can transport exudate through the antimicrobial layer to the sponge layer, while sufficient glucose contact with GOx enhances the antimicrobial properties of the designed Janus wound dressing. Experimental results demonstrate the effectiveness of the cascade effect of GOx@PCL/MOF ENMs, ultimately releasing reactive oxygen species and exhibiting robust antibacterial properties. In vivo animal experiments reveal the ability of the Janus wound dressing to mitigate methicillin-resistant Staphylococcus aureus (MRSA) infections in the early stages, thereby expediting the wound healing process. In vivo animal study, the Janus wound dressing achieved a healing rate of 54% on day 3. Our findings underscore the substantial potential of the Janus wound dressings in promoting the healing of chronic diabetic wounds.

In Situ Formation of Hydrogels Loaded with ZnO Nanoparticles Promotes Healing of Diabetic Wounds in Rats

The challenge of healing diabetic skin wounds presents a significant hurdle in clinical practice and scientific research. In response to this pressing concern, we have developed a temperature-sensitive, in situ-forming hydrogel comprising poly(n-isopropylacrylamide166-co-n-butyl acrylate9) -poly(ethylene glycol) -poly(n-isopropylacrylamide166-co-butyl acrylate9) copolymer, denoted as PEP, in combination with zinc oxide nanoparticles, forming what we refer to as PEP-ZnO hydrogel. The antimicrobial properties of the PEP-ZnO hydrogel against methicillin-resistant Staphylococcus aureus were rigorously assessed by using the bacteriostatic banding method. In vitro evaluations encompassed examinations of hemocompatibility and biocompatibility. The study further employed a diabetic Sprague-Dawley (SD) rat whole-layer trauma model for comprehensive in vivo analyses. In vivo healing assessments revealed the potential of the PEP-ZnO hydrogel, characterized by increased collagen deposition and enhanced vascularization at the trauma site, thus significantly expediting the healing process. Collectively, these findings endorse the PEP-ZnO hydrogel as a safe and effective dressing for addressing chronic wounds in diabetic patients. This hydrogel not only holds promise for improving the quality of life for diabetic individuals grappling with chronic wounds but also represents a noteworthy advancement in wound care.

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.

Thymoquinone loaded nanoemulgel in streptozotocin induced diabetic wound

Aim: To treat diabetic wound healing with a novel Thymoquinone (TQ) loaded nanoformulation by using combination of essentials oils.Methods: TQ nanoemulsion (NE) was developed with seabuckthorn & lavender essential oils by phase inversion method and mixture design. Further, DIAGEL is obtained by incorporating NE into 1% carbopol®934. Furthermore, particle size, polydispersity index, thermodynamic stability studies, rheology, spreadability, drug content, in-vitro drug release, ex-vivo permeation, anti-oxidant assay, antimicrobial studies, angioirritance, HAT-CAM assay, in-vitro and in-vivo studies were determined.Results: NE has a particle size of 17.79 ± 0.61 nm, 0.206 ± 0.012 PDI & found to be thermodynamically stable. DIAGEL exhibited pseudoplastic behavior, sustained drug release, better permeation of TQ and a drug content of 98.54 ± 0.08%. DIAGEL stored for 6 months at room temperature and 2-8°C showed no degradation. Further, an improved angiogenesis, absence of angio-irritancy, remarkable antioxidant and antimicrobial activities against Candida albicans & S. aureus were observed. Cytotoxicity analysis revealed nearly 2.28 -folds higher IC50 value than drug solution. Furthermore, inflammatory mediators were reduced in DIAGEL treated animal groups. The histopathological studies confirmed skin healing with regeneration and granulation of tissue.Conclusion: The novel formulation has strong anti-inflammatory, angiogenesis, antioxidant and appreciable diabetic wound healing properties.

Kill Two Birds with One Stone: Dual-Metal MOF-Nanozyme-Decorated Hydrogels with ROS-Scavenging, Oxygen-Generating, and Antibacterial Abilities for Accelerating Infected Diabetic Wound Healing

Diabetic wounds tend to develop into nonhealing wounds associated with the complex inflammatory microenvironment of uncontrollable bacterial infection, reactive oxygen species (ROS) accumulation, and chronic hypoxia. Damaged blood vessels hinder metabolic circulation, aggravating hypoxia, and ROS accumulation and further exacerbating the diabetic wound microenvironment. However, existing treatments with a single functionality have difficulty healing complicated diabetic wounds. Therefore, developing an integrative strategy to improve the hostility of the diabetic wound microenvironment is urgently needed. Herein, multifunctional genipin (GP)-crosslinked chitosan (CS)-based hydrogels decorated with the biomimetic metal-organic framework (MOF)-nanozymes and the natural antibacterial agent chlorogenic acid (CGA), which is named MOF/CGA@GP-CS (MCGC), are prepared. With catalase (CAT)-like activity, these dual-metal MOF-nanozymes are promising bioreactors for simultaneously alleviating ROS accumulation and hypoxia by converting elevated endogenous H2O2 into dissolved oxygen in diabetic wounds. In addition, the other component of natural polyphenolic CGA acts as a mild antibacterial agent, efficiently inhibiting wound infection and avoiding antibiotic resistance. Impressively, the MCGC hydrogels accelerate infected diabetic wound healing by eliminating oxidative stress, increasing oxygenation, and reversing bacterial infection in vivo. In this work, an effective strategy based on multifunctional hydrogel wound dressings is successfully developed and applied in diabetic wound management.

Multi-mechanism antitumor/antibacterial effects of Cu-EGCG self-assembling nanocomposite in tumor nanotherapy and drug-resistant bacterial wound infections

Chemotherapy and surgery stand as primary cancer treatments, yet the unique traits of the tumor microenvironment hinder their effectiveness. The natural compound epigallocatechin gallate (EGCG) possesses potent anti-tumor and antibacterial traits. However, the tumor's adaptability to chemotherapy due to its acidic pH and elevated glutathione (GSH) levels, coupled with the challenges posed by drug-resistant bacterial infections post-surgery, impede treatment outcomes. To address these challenges, researchers strive to explore innovative treatment strategies, such as multimodal combination therapy. This study successfully synthesized Cu-EGCG, a metal-polyphenol network, and detailly characterized it by using synchrotron radiation and high-resolution mass spectrometry (HRMS). Through chemodynamic therapy (CDT), photothermal therapy (PTT), and photodynamic therapy (PDT), Cu-EGCG showed robust antitumor and antibacterial effects. Cu+ in Cu-EGCG actively participates in a Fenton-like reaction, generating hydroxyl radicals (·OH) upon exposure to hydrogen peroxide (H2O2) and converting to Cu2+. This Cu2+ interacts with GSH, weakening the oxidative stress response of bacteria and tumor cells. Density functional theory (DFT) calculations verified Cu-EGCG's efficient GSH consumption during its reaction with GSH. Additionally, Cu-EGCG exhibited outstanding photothermal conversion when exposed to 808 nm near-infrared (NIR) radiation and produced singlet oxygen (1O2) upon laser irradiation. In both mouse tumor and wound models, Cu-EGCG showcased remarkable antitumor and antibacterial properties.

Advancements of Porphyrin-Derived Nanomaterials for Antibacterial Photodynamic Therapy and Biofilm Eradication

The threat posed by antibiotic-resistant bacteria and the challenge of biofilm formation has highlighted the inadequacies of conventional antibacterial therapies, leading to increased interest in antibacterial photodynamic therapy (aPDT) in recent years. This approach offers advantages such as minimal invasiveness, low systemic toxicity, and notable effectiveness against drug-resistant bacterial strains. Porphyrins and their derivatives, known for their high molar extinction coefficients and singlet oxygen quantum yields, have emerged as crucial photosensitizers in aPDT. However, their practical application is hindered by challenges such as poor water solubility and aggregation-induced quenching. To address these limitations, extensive research has focused on the development of porphyrin-based nanomaterials for aPDT, enhancing the efficacy of photodynamic sterilization and broadening the range of antimicrobial activity. This review provides an overview of various porphyrin-based nanomaterials utilized in aPDT and biofilm eradication in recent years, including porphyrin-loaded inorganic nanoparticles, porphyrin-based polymer assemblies, supramolecular assemblies, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). Additionally, insights into the prospects of aPDT is offered, highlighting its potential for practical implementation.

Progress in antibacterial applications of nanozymes

Bacterial infections are a growing problem, and antibiotic drugs can be widely used to fight bacterial infections. However, the overuse of antibiotics and the evolution of bacteria have led to the emergence of drug-resistant bacteria, severely reducing the effectiveness of treatment. Therefore, it is very important to develop new effective antibacterial strategies to fight multi-drug resistant bacteria. Nanozyme is a kind of enzyme-like catalytic nanomaterials with unique physical and chemical properties, high stability, structural diversity, adjustable catalytic activity, low cost, easy storage and so on. In addition, nanozymes also have excellent broad-spectrum antibacterial properties and good biocompatibility, showing broad application prospects in the field of antibacterial. In this paper, we reviewed the research progress of antibacterial application of nanozymes. At first, the antibacterial mechanism of nanozymes was summarized, and then the application of nanozymes in antibacterial was introduced. Finally, the challenges of the application of antibacterial nanozymes were discussed, and the development prospect of antibacterial nanozymes was clarified.

Carbon dots-supported Zn single atom nanozymes for the catalytic therapy of diabetic wounds

Diabetic wound treatment continues to be a significant clinical issue due to higher levels of oxidative stress, susceptibility to bacterial infections, and chronic inflammatory responses during healing. We rationally developed and synthesized an ultra-small carbon dots (C-dots) loaded with zinc single-atom nanozyme (Zn/C-dots) with the aim of promoting wounds healing by nanocatalytic treatment, especially targeting its complex pathological microenvironment. Zinc single atoms and C-dots form a dual catalytic system with higher enzymatic activity. Furthermore, the Zn/C-dots nanozyme effectively enters cells, accumulates at mitochondria, and removes excess ROS, protecting cells from oxidative stress damage and limiting the release of pro-inflammatory cytokines, hence reducing inflammation. Zinc can synergistically increase the antibacterial action of C-dots (the effective antibacterial rate of 100 µg/mL Zn/C-dots was above 90 %). Unlike traditional C-dots, Zn/C-dots can cause endothelial cell migration and the formation of new blood vessels. In vitro cytotoxicity, blood compatibility, and in vivo toxicity studies of Zn/C-dots show that they are biocompatible. We subsequently utilized the Zn/C-dots nanozymes to treat diabetic rats' chronic wounds for external use, combining them with ROS-responsive hydrogels to create an antioxidative system (H-Zn/C-dots). The hydrogels anchored the Zn/C-dots nanozymes to the wound, allowing for long-term treatment. The results revealed that H-Zn/C-dots can considerably reduce inflammation, accelerate angiogenesis, collagen deposition, and promote tissue remodeling at the diabetic wound site. After 14 days, the wound area had decreased to approximately 9.19 %, making it a potential treatment. STATEMENT OF SIGNIFICANCE: An ultra-small carbon dot with a zinc single-atom nanozyme was designed and manufactured. Zn/C-dots possess antibacterial, ROS-scavenging, and angiogenesis activities. In vivo, the multifunctional ROS-responsive hydrogel incorporating Zn/C-dots could speed up diabetic wound healing.

Bioinspired shape-changing nanofiber dressings for intelligent wrapping and promoting healing of superficial wounds

The use of dressings in clinical settings is common for the purpose of wound wrapping and creating an optimal microenvironment to enhance the healing process. Proper coverage of wounds with dressings serves as the fundamental basis for effective wound healing. Unfortunately, non-standard coverage by hands can cause pain and secondary damage to patients, while slow manual application during treatment of extensive burns may increase the risk of wound infection. Herein, drawing inspiration from the microstructure and hygroscopic deformation observed in pine cones, we propose a polyvinyl alcohol/polysulfone (PVA/PSF) smart dressing. This bioinspired smart dressing exhibits rapid bending deformation under high moisture condition, allowing easy adjustment of bending amplitude, speed, and direction. Moreover, the smart dressing is capable of rapid bending and autonomous wrapping around "artificial wounds" on a doll's body, as well as fitting irregularly shaped "hand wounds" and extensive "arm wounds" on human subjects. By integrating two layers into one dressing design, we endow it with dual functionality: The hygroscopic PVA layer facilitates transversal liquid transport to effectively reduce exudate accumulation in the wound bed while maintaining proper moisture levels; meanwhile, the highly hydrophobic PSF layer repels various aqueous solutions to protect against external contaminants. In vivo results confirm that this multifunctional smart dressing promotes collagen synthesis and accelerates angiogenesis for accelerated wound healing. We believe that this innovative multifunctional approach to wound management will provide valuable insights into wound healing therapy.

Application of metal-organic framework materials in regenerative medicine

In the past few decades, scaffolds manufactured from composite or hybrid biomaterials of natural or synthetic origin have made great strides in enhancing wound healing and repairing fractures and pathological bone loss. However, the prevailing use of such scaffolds in tissue engineering is accompanied by numerous constraints, including low mechanical stability, poor biological activity, and impaired cell proliferation and differentiation. The performance of scaffolds in wound and bone tissue engineering may be enhanced by some modifications in the synthesis of nanoscale metal-organic framework (nano-MOF) scaffolds. Nano-MOFs have attracted researchers' attention in recent years due to their distinctive features, which include tenability, biocompatibility, good mechanical stability, and ultrahigh surface area. The biological properties of scaffolds are enhanced and tissue regeneration is facilitated by the introduction of nano-MOFs. Moreover, the physicochemical characteristics, drug loading, and ion release capacities of the scaffolds are improved by the nanoscale structure and topological features of nano-MOFs, which also control stem cell differentiation, proliferation, and attachment. This review provides further comprehensive detail about the most recent uses of nano-MOFs in tissue engineering. The distinct characteristics of nano-MOFs are explored in enhancing tissue repair, wound healing, osteoinduction, and bone conductivity. Significant attributes include high antibacterial activity, substantial drug-loading capacity, and the ability to regulate drug release. Finally, this discussion addresses the obstacles, clinical impediments, and considerations encountered in the application of these nanomaterials to diverse scaffolds, tissue-mimicking structures, dressings, fillers, and implants for bone tissue repair and wound healing.

An injectable chitosan-based hydrogel incorporating carbon dots with dual enzyme-mimic activities for synergistically treatment of bacteria infected wounds

Bacterial infections pose a serious threat to human health, and the emergence of superbugs and the growing antibiotic resistance phenomenon have made the development of novel antimicrobial products. In this paper, an ultrasmall Cu, N co-doped carbon dots (CDs-Cu-N) with excellent peroxidase mimic activity and enhanced catalase mimic activity was successfully prepared and anchored to an injectable chitosan (CS)-based hybrid hydrogel. As expected, the CDs-Cu-N-H2O2-CS hybrid hydrogel maintains the excellent enzyme-mimicking properties of CDs-Cu-N and shows superior antibacterial property, which has been proven to effectively promote the healing of S. aureus-infected wounds with good biocompatibility. Benefitting from the dual-enzyme-mimic activity of CDs-Cu-N, the hybrid hydrogel not only can catalyze the generation of highly toxic ROS from low concentration of H2O2 to inhibit the bacterial infections, but also can significantly promote the wound tissue repair and regeneration by improving the anoxic microenvironment and promoting neovascularization. In addition, this hybrid hydrogel also possessed excellent injectability and moldability. It can adapt to various the irregular shapes of acute wounds, maintaining a moist and safe microenvironment while prolonging the action time of nanozyme on wounds, thus promoting wound healing. This injectable hybrid hydrogel shows great potential applications in the field of wound infection management.

Seeking Cells, Targeting Bacteria: A Cascade-Targeting Bacteria-Responsive Nanosystem for Combating Intracellular Bacterial Infections

Intracellular bacteria pose a great challenge to antimicrobial therapy due to various physiological barriers at both cellular and bacterial levels, which impede drug penetration and intracellular targeting, thereby fostering antibiotic resistance and yielding suboptimal treatment outcomes. Herein, a cascade-target bacterial-responsive drug delivery nanosystem, MM@SPE NPs, comprising a macrophage membrane (MM) shell and a core of SPE NPs. SPE NPs consist of phenylboronic acid-grafted dendritic mesoporous silica nanoparticles (SP NPs) encapsulated with epigallocatechin-3-gallate (EGCG), a non-antibiotic antibacterial component, via pH-sensitive boronic ester bonds are introduced. Upon administration, MM@SPE NPs actively home in on infected macrophages due to the homologous targeting properties of the MM shell, which is subsequently disrupted during cellular endocytosis. Within the cellular environment, SPE NPs expose and spontaneously accumulate around intracellular bacteria through their bacteria-targeting phenylboronic acid groups. The acidic bacterial microenvironment further triggers the breakage of boronic ester bonds between SP NPs and EGCG, allowing the bacterial-responsive release of EGCG for localized intracellular antibacterial effects. The efficacy of MM@SPE NPs in precisely eliminating intracellular bacteria is validated in two rat models of intracellular bacterial infections. This cascade-targeting responsive system offers new solutions for treating intracellular bacterial infections while minimizing the risk of drug resistance.

A carrier-free, injectable, and self-assembling hydrogel based on carvacrol and glycyrrhizin exhibits high antibacterial activity and enhances healing of MRSA-infected wounds

Inspired by glycyrrhizin's strong pharmacological activities and the directed self-assembly into hydrogels, we created a novel carrier-free, injectable hydrogel (CAR@glycygel) by combining glycyrrhizin with carvacrol (CAR), without any other chemical crosslinkers, to promote wound healing on bacteria-infected skin. CAR appeared to readily dissolve and load into CAR@glycygel. CAR@glycygel had a dense, porous, sponge structure and strong antioxidant characteristics. In vitro, it showed better antibacterial ability than free CAR. For methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Escherichia coli, the diameter of inhibition zone values of CAR@glycygel were 3.80 ± 0.04, 3.31 ± 0.20 and 3.12 ± 0.24 times greater, respectively, than those of free CAR. The MICs for CAR@glycygel was 156.25 μg/mL while it was 1250.00 μg/mL for free CAR to these three bacteria. Its antibacterial mechanism appeared to involve destruction of the integrity of the bacterial cell wall and biomembrane, leading to a leakage of AKP and inhibition of biofilm formation. In vivo, CAR@glycygel effectively stopped bleeding. When applied to skin wounds on rats infected with MRSA, CAR@glycygel had strong bactericidal activity and improved wound healing. The wound healing rates for CAR@glycygel were 49.59 ± 15.78 %, 93.02 ± 3.09 % and 99.02 ± 0.55 % on day 3, day 7, and day 11, respectively, which were much better than blank control and positive control groups. Mechanisms of CAR@glycygel accelerating wound healing involved facilitating epidermis remolding, promoting the growth of hair follicles, stimulating collagen deposition, mitigating inflammation, and promoting angiogenesis. Overall, CAR@glycygel showed great potential as wound dressing for infected skin wounds.

Emerging Nanotherapeutic Approaches for Diabetic Wound Healing

Diabetic wounds pose a significant challenge in modern healthcare due to their chronic and complex nature, often resulting in delayed healing, infections, and, in severe cases, amputations. In recent years, nanotherapeutic approaches have emerged as promising strategies to address the unique pathophysiological characteristics of diabetic wounds. This review paper provides a comprehensive overview of the latest advancements in nanotherapeutics for diabetic wound treatment. We discuss various nanomaterials and delivery systems employed in these emerging therapies. Furthermore, we explore the integration of biomaterials to enhance the efficacy of nanotherapeutic interventions. By examining the current state-of-the-art research, challenges, and prospects, this review aims to offer valuable insights for researchers, clinicians, and healthcare professionals working in the field of diabetic wound care.

Effect and mechanism of natural composite hydrogel from fish scale intercellular matrix on diabetic chronic wound repair

Diabetes mellitus is a chronic metabolic disease with prolonged low-grade inflammation and impaired cellular function, leading to poor wound healing. The treatment of diabetic wounds remains challenging due to the complex wound microenvironment. In view of the prominence of fish scales in traditional Chinese medicine and their wide application in modern medicine, we isolated the intercellular components in the scales of sea bass, obtained a natural composite hydrogel, fish scales gel (FSG), and applied it to diabetic chronic wounds. FSG was rich in collagen-like proteins, and possessed low-temperature gelation properties. In vitro, FSG was biocompatible and promoted fibroblast proliferation by approximately 40 %, endothelial cell migration by approximately 20 % and activated the M1 macrophages. In addition, FSG restored the function of fibroblasts and vascular endothelial cells damaged by high glucose. Importantly, FSG normalized the acute inflammatory response to impaired macrophages in a high-glucose microenvironment. Transcriptome analysis implies that this mechanism may involve enhanced cell signaling and cellular communication, improved sensitivity to cytokines, and activation of the TNF signaling pathway. Animal experiments confirmed that FSG significantly improved wound closure by approximately 15 % in diabetic rats, showing similar effects to acute wounds. In conclusion, the regulation of multiple cellular functions by FSG, especially the counterintuitive ability to induce acute inflammation, promoted diabetic wound healing and provides a novel therapeutic strategy for wound repair in diabetic patients.

Nanozymes for the Therapeutic Treatment of Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are chronic, refractory wounds caused by diabetic neuropathy, vascular disease, and bacterial infection, and have become one of the most serious and persistent complications of diabetes mellitus because of their high incidence and difficulty in healing. Its malignancy results from a complex microenvironment that includes a series of unfriendly physiological states secondary to hyperglycemia, such as recurrent infections, excessive oxidative stress, persistent inflammation, and ischemia and hypoxia. However, current common clinical treatments, such as antibiotic therapy, insulin therapy, surgical debridement, and conventional wound dressings all have drawbacks, and suboptimal outcomes exacerbate the financial and physical burdens of diabetic patients. Therefore, development of new, effective and affordable treatments for DFU represents a top priority to improve the quality of life of diabetic patients. In recent years, nanozymes-based diabetic wound therapy systems have been attracting extensive interest by integrating the unique advantages of nanomaterials and natural enzymes. Compared with natural enzymes, nanozymes possess more stable catalytic activity, lower production cost and greater maneuverability. Remarkably, many nanozymes possess multienzyme activities that can cascade multiple enzyme-catalyzed reactions simultaneously throughout the recovery process of DFU. Additionally, their favorable photothermal-acoustic properties can be exploited for further enhancement of the therapeutic effects. In this review we first describe the characteristic pathological microenvironment of DFU, then discuss the therapeutic mechanisms and applications of nanozymes in DFU healing, and finally, highlight the challenges and perspectives of nanozyme development for DFU treatment.

Application of metal-organic frameworks in infectious wound healing

Metal-organic frameworks (MOFs) are metal-organic skeleton compounds composed of self-assembled metal ions or clusters and organic ligands. MOF materials often have porous structures, high specific surface areas, uniform and adjustable pores, high surface activity and easy modification and have a wide range of prospects for application. MOFs have been widely used. In recent years, with the continuous expansion of MOF materials, they have also achieved remarkable results in the field of antimicrobial agents. In this review, the structural composition and synthetic modification of MOF materials are introduced in detail, and the antimicrobial mechanisms and applications of these materials in the healing of infected wounds are described. Moreover, the opportunities and challenges encountered in the development of MOF materials are presented, and we expect that additional MOF materials with high biosafety and efficient antimicrobial capacity will be developed in the future.

MOFs and MOF-Based Composites as Next-Generation Materials for Wound Healing and Dressings

In recent years, there has been growing interest in developing innovative materials and therapeutic strategies to enhance wound healing outcomes, especially for chronic wounds and antimicrobial resistance. Metal-organic frameworks (MOFs) represent a promising class of materials for next-generation wound healing and dressings. Their high surface area, pore structures, stimuli-responsiveness, antibacterial properties, biocompatibility, and potential for combination therapies make them suitable for complex wound care challenges. MOF-based composites promote cell proliferation, angiogenesis, and matrix synthesis, acting as carriers for bioactive molecules and promoting tissue regeneration. They also have stimuli-responsivity, enabling photothermal therapies for skin cancer and infections. Herein, a critical analysis of the current state of research on MOFs and MOF-based composites for wound healing and dressings is provided, offering valuable insights into the potential applications, challenges, and future directions in this field. This literature review has targeted the multifunctionality nature of MOFs in wound-disease therapy and healing from different aspects and discussed the most recent advancements made in the field. In this context, the potential reader will find how the MOFs contributed to this field to yield more effective, functional, and innovative dressings and how they lead to the next generation of biomaterials for skin therapy and regeneration.

Comparison of Lignocellulose Nanofibrils Extracted from Bamboo Fibrous and Parenchymal Tissues and the Properties of Resulting Films

Bamboo is composed of thick-walled fibrous tissue and thin-walled parenchymal tissue. To compare the energy consumption of preparing lignocellulose nanofibrils (LCNF) from these bamboo tissues, the crystallinity, sol. viscosity, morphology and mechanical properties of LCNF at different preparation stages were characterized in detail. It required at least nine homogenization cycles for dissociating the fibrous tissue, but only six cycles for the parenchymal tissue. The average diameter of LCNF isolated from fibrous and parenchymal tissues was 45.1 nm and 36.2 nm, respectively. The tensile strength of the LCNF film prepared from parenchymal tissue reached 142.46 MPa, whereas the film from fibrous tissue reached only 122.82 MPa. Additionally, a metal organic framework (MOF) was used to produce MOF-LCNF film with enhanced UV protection and antibacterial properties. The results indicated that the energy consumption for preparing LCNF from parenchymal tissue is significantly lower than that for preparing LCNF from fibrous tissue. This study offers a low-cost and eco-friendly method for preparing LCNF, promoting the precise utilization of different tissues from bamboo based on their unique characteristics.

pH‑responsive nanozyme cascade catalysis: A strategy of BiVO4 application for modulation of pathological wound microenvironment

Persistent inflammation and bacterial infection commonly occur during the wound healing process, necessitating urgent development of effective strategies for treating drug-resistant bacterial infections. In this study, bismuth vanadate (BiVO4) was successfully synthesized as an antibacterial agent that promotes wound healing. Through In vitro antibacterial experiments, it was observed that the prepared BiVO4 exhibited excellent performance in catalyzing H2O2 to produce hydroxyl radicals (OH) at a lower concentration (0.2 mg mL-1), resulting in significant antibacterial effects against Gram-negative Extended-Spectrum β-Lactamases-Producing Escherichia coli (ESBL-E. coli) strains. Furthermore, biosafety tests, cell scratch experiments, and ESBL-E. coli infected wound rat model experiments demonstrated high biocompatibility of BiVO4 with a cell survival rate exceeding 85 %. Additionally, BiVO4 promoted the production of vascular endothelial growth factors and fibroblasts migration while contributing to collagen production, effectively facilitating immune reconstruction at the wound site. By integrating peroxidase (POD)-like under acidic conditions (pH 4) and catalase (CAT)-like catalytic activities at under neutral conditions (pH 7), BiVO4 exhibited the ability to activate free radical sterilization and accelerate wound healing by activating O2. Therefore, our findings provide evidence for a dual enzyme regulatory mechanism involving antibacterial properties and promotion of wound tissue reconstruction for potential application in both antibacterial treatment and wound healing.

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.

Hesperidin - loaded PVA/alginate hydrogel: targeting NFκB/iNOS/COX-2/TNF-α inflammatory signaling pathway

Introduction

Skin injuries represent a prevalent form of physical trauma, necessitating effective therapeutic strategies to expedite the wound healing process. Hesperidin, a bioflavonoid naturally occurring in citrus fruits, exhibits a range of pharmacological attributes, including antimicrobial, antioxidant, anti-inflammatory, anticoagulant, and analgesic properties. The main objective of the study was to formulate a hydrogel with the intention of addressing skin conditions, particularly wound healing.

Methods

This research introduces a methodology for the fabrication of a membrane composed of a Polyvinyl alcohol - Sodium Alginate (PVA/A) blend, along with the inclusion of an anti-inflammatory agent, Hesperidin (H), which exhibits promising wound healing capabilities. A uniform layer of a homogeneous solution comprising PVA/A was cast. The process of crosslinking and the enhancement of hydrogel characteristics were achieved through the application of gamma irradiation at a dosage of 30 kGy. The membrane was immersed in a Hesperidin (H) solution, facilitating the permeation and absorption of the drug. The resultant system is designed to deliver H in a controlled and sustained manner, which is crucial for promoting efficient wound healing. The obtained PVA/AH hydrogel was evaluated for cytotoxicity, antioxidant and free radical scavenging activities, anti-inflammatory and membrane stability effect. In addition, its action on oxidative stress, and inflammatory markers was evaluated on BJ-1 human normal skin cell line.

Results and Discussion

We determined the effect of radical scavenging activity PVA/A (49 %) and PVA/AH (87%), the inhibition of Human red blood cell membrane hemolysis by PVA/AH (81.97 and 84.34 %), hypotonicity (83.68 and 76.48 %) and protein denaturation (83.17 and 85.8 %) as compared to 250 μg/ml diclofenac (Dic.) and aspirin (Asp.), respectively. Furthermore, gene expression analysis revealed an increased expression of genes associated with anti-oxidant and anti-inflammatory properties and downregulated TNFα, NFκB, iNOS, and COX2 by 67, 52, 58 and 60%, respectively, by PVA/AH hydrogel compared to LPS-stimulated BJ-1 cells. The advantages associated with Hesperidin can be ascribed to its antioxidant and anti-inflammatory attributes. The incorporation of Hesperidin into hydrogels offers promise for the development of a novel, secure, and efficient strategy for wound healing. This innovative approach holds potential as a solution for wound healing, capitalizing on the collaborative qualities of PVA/AH and gamma irradiation, which can be combined to establish a drug delivery platform for Hesperidin.

Multifunctional nanocomposites mediated novel hydrogel for diabetic wound repair

The regeneration and repair of diabetic wounds, especially those including bacterial infection, have always been difficult and challenging using current treatment. Herein, an effective strategy is reported for constructing glucose-responsive functional hydrogels using nanocomposites as nodes. In fact, tannic acid (TA)-modified ceria nanocomposites (CNPs) and a zinc metal-organic framework (ZIF-8) were employed as nodes. Subsequent crosslinking with 3-acrylamidophenylboronic acid achieved functional nanocomposite-hydrogels (TA@CN gel, TA@ZMG gel) by radical-mediated polymerization. Compared with a simple physically mixed hydrogel system, the mechanical properties of TA@CN gel and TA@ZMG gel are significantly enhanced due to the intervention of the nanocomposite nodes. In addition, this kind of nanocomposite hydrogel can realize the programmed loading of drugs and release of drugs in response to glucose/PH, to coordinate and promote its application in the regeneration and repair of diabetic wounds and infected diabetic wounds. Specifically, TA@CN gel can remove reactive oxygen species and generate oxygen through its various enzymatic activities. At the same time, it can effectively promote neovascularization, thus promoting the regeneration and repair of diabetic wounds. Furthermore, glucose oxidase-loaded TA@ZMG gel exhibits glucose response and pH-regulating functions, triggering programmed metformin (Met) release by degrading the metal-organic framework (MOF) backbone. It also exhibited additional synergistic effects of antibacterial activity, hair regeneration and systemic blood glucose regulation, which make it suitable for the repair of more complex infected diabetic wounds. Overall, this novel nanocomposite-mediated hydrogel holds great potential as a biomaterial for the healing of chronic diabetic wounds, opening up new avenues for further biomedical applications.

A Comparative Analysis of the Antibacterial Spectrum of Ultrasmall Manganese Ferrite Nanozymes with Varied Surface Modifications

Bacterial infectious diseases pose a significant global challenge. However, conventional antibacterial agents exhibit limited therapeutic effectiveness due to the emergence of drug resistance, necessitating the exploration of novel antibacterial strategies. Nanozymes have emerged as a highly promising alternative to antibiotics, owing to their particular catalytic activities against pathogens. Herein, we synthesized ultrasmall-sized MnFe2O4 nanozymes with different charges (MnFe2O4-COOH, MnFe2O4-PEG, MnFe2O4-NH2) and assessed their antibacterial capabilities. It was found that MnFe2O4 nanozymes exhibited both antibacterial and antibiofilm properties attributed to their excellent peroxidase-like activities and small sizes, enabling them to penetrate biofilms and interact with bacteria. Moreover, MnFe2O4 nanozymes effectively expedite wound healing within 12 days and facilitate tissue repair and regeneration while concurrently reducing inflammation. MnFe2O4-COOH displayed favorable antibacterial activity against Gram-positive bacteria, with 80% bacterial removal efficiency against MRSA by interacting with phosphatidylglycerol (PG) and cardiolipin (CL) of the membrane. By interacting with negatively charged bacteria surfaces, MnFe2O4-NH2 demonstrated the most significant and broad-spectrum antibacterial activity, with 95 and 85% removal efficiency against methicillin-resistant Staphylococcus aureus (MRSA) and P. aeruginosa, respectively. MnFe2O4-PEG dissipated membrane potential and reduced ATP levels in MRSA and P. aeruginosa, showing relatively broad-spectrum antibacterial activity. To conclude, MnFe2O4 nanozymes offer a promising therapeutic approach for treating wound infections.

Multicargo-loaded inverse opal gelatin hydrogel microparticles for promoting bacteria-infected wound healing

Nowadays, many strategies have been developed to design biomaterials to accelerate bacteria-infected wound healing. Here, we presented a new type of multicargo-loaded inverse opal hydrogel microparticle (IOHM) for regulating oxidative stress, antibiosis, and angiogenesis of the bacteria-infected wound. The methacrylate acylated gelatin (GelMA)-based inverse opal hydrogel microparticles (IOHMs) were obtained by using the colloidal crystal microparticles as templates, and fullerol, silver nanoparticles (Ag NPs), and vascular endothelial growth factor (VEGF) were loaded in IOHMs. The developed multicargo-loaded IOHMs displayed good size distribution and biocompatibility, and when they were applied in cell culture, bacteria culture, and animal experiments, they exhibited excellent anti-oxidative stress properties, antibacterial properties, and angiogenesis. These characteristics of the developed multicargo-loaded IOHMs make them ideal for bacteria-infected wound healing.

Hydrogels Containing Chitosan-Modified Gold Nanoparticles Show Significant Efficacy in Healing Diabetic Wounds Infected with Antibiotic-Resistant Bacteria

Purpose

Persistent Infections and inflammation are associated with impaired wound healing in diabetic patients. There is a pressing demand for innovative antimicrobial strategies to address infections arising from antibiotic-resistant bacteria. Polymer-modified gold nanoparticles (AuNPs) show broad-spectrum antibacterial properties and significant biocompatibility. This study investigated the antibacterial and wound healing efficacy of hydrogel dressings conjugated with chitosan-AuNPs in diabetic model rats.

Methods

Chitosan (CS)-functionalized gold nanoparticles (CS-AuNPs) were incorporated into hydrogel dressings (Gel/CS-AuNPs), which were formulated through the chemical cross-linking of gelatin with sodium alginate (SA). The basic characteristics of Gel/CS-AuNPs were analyzed by TEM, SEM, XRD, and UV-visible spectra. Rheological, swelling, degradation, and adhesive properties of Gel/CS-AuNPs were also determined. In vitro anti-bactericidal effects of the Gel/CS-AuNPs were analyzed with E. coli, S. aureus, and MRSA. In vitro biocompatibility of the Gel/CS-AuNPs was evaluated using NIH3T3 cells. The in vivo antibacterial and wound healing efficacy of the Gel/CS-AuNPs was analyzed in the diabetic wound model rats. Histological and immunofluorescence staining were performed to determine the status of angiogenesis, epithelization, inflammation response, and collagen deposition.

Results

Gel/CS-AuNPs demonstrated significant high biodegradability, water absorption bactericidal, and biocompatibility, and slight adhesiveness. Gel/CS-AuNPs exhibited pronounced antibacterial efficacy against gram-negative, gram-positive, and MRSA in a CS-AuNPs-dose-dependent manner. In the diabetic wound model rats, Gel/CS-AuNPs effectively killed MRSA, reduced inflammation, and promoted angiogenesis and collagen deposition and remodeling at the wound site. As a result, Gel/CS-AuNPs expedited the recovery process for infected diabetic wounds. Among the hydrogels with different CS-AuNPs concentrations, Gel/CS-Au25 with 25% CS-AuNPs showed the best bactericidal and wound healing performance.

Conclusion

Gel/CS-AuNPs significantly improve the healing of MRSA-infected diabetic wounds in the rat model. Therefore, Gel/CS-AuNPs show great promise for the treatment of diabetic infection wound healing.

Enhanced Photocatalytic Properties of All-Organic IDT-COOH/O-CN S-Scheme Heterojunctions Through π-π Interaction and Internal Electric Field

Herein, we present a distinct methodology for the in situ electrostatic assembly method for synthesizing a conjugated (IDT-COOH)/oxygen-doped g-C3N4 (O-CN) S-scheme heterojunction. The electron delocalization effect due to π-π interactions between O-CN and self-assembled IDT-COOH favors interfacial charge separation. The self-assembled IDT-COOH/O-CN exhibits a broadened visible absorption to generate more charge carriers. The internal electric field between the IDT-COOH and the O-CN interface provides a directional charge-transfer channel to increase the utilization of photoinduced charge carriers. Moreover, the active species (•O2-, h+, and 1O2) produced by IDT-COOH/O-CN under visible light play important roles in photocatalytic disinfection. The optimum 40% IDT-COOH/O-CN can kill 7-log of methicillin-resistant Staphylococcus aureus (MRSA) cells in 2 h and remove 88% tetracycline (TC) in 5 h, while O-CN only inactivates 1-log of MRSA cells and degrades 40% TC. This work contributes to a promising method to fabricate all-organic g-C3N4-based S-scheme heterojunction photocatalysts with a wide range of optical responses and enhanced exciton dissociation.

Application of metal-organic frameworks-based functional composite scaffolds in tissue engineering

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.