Multifaceted Catalytic ROS-Scavenging via Electronic Modulated Metal Oxides for Regulating Stem Cell Fate

Ultrasound Trigger Ultrasmall Multifunction Nanobubbles for Thrombus Visual Treatment

Intravenous injection of thrombolytic drugs is the prevailing strategy for the treatment of thrombotic disease. However, its applications are limited due to hemorrhagic risk and thrombus microenvironment. In pursuit of visualized thrombolysis and inspired by the excessive reactive oxygen species (ROS) and inflammatory factors within the thrombus site, an ultrasmall nanobubble (CeO2/MnOX@UK@PFP) for integration of imaging and therapy by low intensity pulse ultrasound (LIPUS) trigger is designed, which achieved the visual delivery of Urokinas (UK) and ROS scavenging agents to adjust thrombus microenvironment. In this study, CeO2/MnOX with ROS scavenging activity are prepared and wrapped with UK and perfluoropentane (PFP) by lipid layer, forming a CeO2/MnOX@UK@PFP. Under LIPUS, PFP undergoes phase transition from liquid to gas for real-time imaging, meanwhile, CeO2/MnOX@UK@PFP is burst to release UK and CeO2/MnOX. UK is delivered to the side of the clot avoiding hemorrhagic risk. CeO2/MnOX@UK@PFP not only can detect the progression of thrombolytic treatment through ultrasound imaging (US) in real-time but also play an important role in the elimination of excessive ROS at the thrombus microenvironment for protecting endangium. Taken together, the in vitro and in vivo experiments illustrated that CeO2/MnOX@UK@PFP displayed excellent efficiency in thrombolysis visual, anti-inflammation, and ROS scavenging.

Advances in the Treatment of Spinal Cord Injury with Nanozymes

Spinal cord injury (SCI) with increasing incidence can lead to severe disability. The pathological process involves complex mechanisms such as oxidative stress, inflammation, and neuron apoptosis. Current treatment strategies focusing on the relief of oxidative stress and inflammation have achieved good effects, while many problems and challenges remain such as the side effect and short half-life of the therapeutic agents. Nanozymes exhibiting good biocatalytic activities can sustainably scavenge free radicals, inhibit neuroinflammation, and protect the neurons. With high stability in physiological conditions and cost-effectiveness, the nanozymes provide a new strategy for SCI treatment. In this Review, we outline the advances of nanozymes and their enzyme-mimicking activities and highlight the progress in the intervention of SCI-adopting nanozymes. We also propose future directions and clinical translation for the nanozyme strategy against SCI.

Injectable Microspheres With Cartilage-Like Structure Facilitate Inflammation Inhibition and Tissue Regeneration

The unique structure of cartilage tissue, characterized by a robust collagen fiber framework and a dynamic proteoglycan hydrogel filling, is crucial for maintaining biomechanical and biochemical homeostasis. Herein, a cartilage-inspired microsphere with sponge framework and hydrogel filling (SponGel MS) is successfully prepared to restore cartilage homeostasis. Specifically, epigallocatechin gallate nanoparticles coated with MnO2 (MnO2@EGCG) are first synthesized, which can scavenge H2O2 and hydroxyl radicals. The formation of SponGel MS involves sequential fabrication of the sponge phase through cryogenic radical reaction and hydrogel phase via Schiff base reaction. The hydrogel phase can dynamically release MnO2@EGCG to inhibit inflammation and SDF-1 to recruit stem cells. Porous sponge phase with favorable compressive performance and His-Ala-Val (HAV) peptide provides stable stem cell niches to regulate stem cell condensation, co-assembly and chondrogenic differentiation. Animal experiments demonstrate that SponGel MS suppresses the expression of IL-1β and collagen I, ultimately achieving cartilage regeneration. This study represents a novel strategy for constructing cartilage repair materials.

Engineered Stem Cell Booster Breaks Pathological Barriers to Treat Chronic Pancreatitis

Chronic pancreatitis (CP) is a long-standing progressive fibrosis and has long been considered incurable, which remains a heavy health burden worldwide. Mesenchymal stem cells (MSCs) with anti-fibrosis properties are currently used in the treatment of fibroinflammatory diseases. However, its therapeutic effect is limited mainly due to two main types of pathological barriers in CP: 1) Fibrotic collagen hinders cell delivery, and 2) Malignant microenvironment attacks cell inactivation. Here, a MSCs-based exogenous nitric oxide (NO) delivery system (MSCs-Lip@RNO) is constructed. In the MSCs-Lip@RNO, NO not only can be a cell booster to regulate collagen fibers, relieve the vascular compression and enhance the accumulation of MSCs in the whole pancreas, but also can form a protective gas layer on the cell surface, which enhances the therapeutic effect of MSCs. In the CP rat model, the pancreatic injury and fibrosis are reduced with 7 days after a single dose administration of this long-acting MSCs. Collectively, this study offers a promising strategy for enhancing the delivery and therapeutic efficacy of MSCs to break pathological barriers in CP treatment.

Bioinspired Spatially Ordered Multicellular Lobules for Liver Regeneration

Cell therapy is a promising strategy for acute liver failure (ALF), while its therapeutic efficacy is often limited by cell loss and poor arrangement. Here, inspired by liver microunits, we propose a novel spatially ordered multicellular lobules for the ALF treatment by using a microfluidic continuous spinning technology. The microfluidics with multiple microchannels was constructed by assembling parallel capillaries. Sodium alginate (Alg) solution encapsulating human umbilical vein endothelial cells (HUVECs), hepatocytes, and mesenchymal stem cells (MSCs) are introduced into the middle channel and the 6 parallel outer channels of the microfluidics, respectively. Simultaneously, Ca2+-loaded solutions are pumped through the innermost and outermost channels, forming a hollow microfiber with hepatocytes and MSCs alternately surrounding the HUVECs. These microfibers could highly resemble the cord-like structure of liver lobules, bringing about outstanding liver-like functions. We have demonstrated that in ALF rats, our biomimetic lobules can effectively suppress excessive inflammatory responses, decrease cell necrosis, and promote regenerative pathways, leading to satisfied therapeutic efficacy. These findings underscore the potential of spatially ordered multicellular microfibers in treating related diseases and improving traditional clinical methods.

Improved Black Phosphorus Nanocomposite Hydrogel for Bone Defect Repairing: Mechanisms for Advancing Osteogenesis

Bone defects caused by fractures and diseases often do not heal spontaneously. They require external agents for repair and regeneration. Bone tissue engineering is emerging as a promising alternative to traditional therapies like autografts and allografts. Nanobiomaterials enhance osteoblast resistance to harsh environments by promoting cell differentiation. Black phosphorus (BP), a novel 2D material in biomedicine, displays unique osteogenic and antimicrobial properties. However, BP nanosheets still face clinical limitations like rapid degradation and high-dose cytotoxicity. To address these, the introduction of amino-silicon phthalocyanine (SiPc-NH2) is investigated to see if it can enhance BP dispersion, reduce BP oxidation, and improve stability and safety for better osteogenesis and antibacterial effects through noncovalent interactions (van der Waals, π-π stacking and electrostatic interactions). Here, the self-healing hydrogel is successfully designed using a step-by-step co-assembly of BP and SiPc-NH2. SiPc-NH2 as a "structural stabilizer" of BP nanosheets reconstructed well-dispersed BP-SiPc-NH2 nanosheets, which improves the biocompatibility of BP, reduces oxidation and enhances photothermal conversion, guaranteeing osteogenic and antimicrobial properties. Furthermore, findings show BP-SiPc-NH2-induced mitochondrial changes support osteogenesis by regulating the crosstalk between Hippo and Wnt signaling pathways-mediated mitochondrial homeostasis, and boosting cellular bioenergetics. Overall, this mitochondrial morphology-based BP-SiPc-NH2 strategy holds great promise for bone repair applications.

MnO2@CeOx-GAMP radiosensitizer with oxygen vacancies depended mimicking enzyme-like activities for radiosensitization-mediated STING pathway activation

Activation of the stimulator of interferon genes (STING) pathway by radiotherapy (RT) has a significant effect on eliciting antitumor immune responses. The generation of hydroxyl radical (·OH) storm and the sensitization of STING-relative catalytic reactions could improve radiosensitization-mediated STING activation. Herein, multi-functional radiosensitizer with oxygen vacancies depended mimicking enzyme-like activities was fabricated to produce more dsDNA which benefits intracellular 2', 3'-cyclic GMP-AMP (cGAMP) generation, together with introducing exogenous cGAMP to activate immune response. MnO2@CeOx nanozymes present enhanced superoxide dismutase (SOD)-like and peroxidase (POD)-like activities due to induced oxygen vacancies accelerate the redox cycles from Ce4+ to Ce3+ via intermetallic charge transfer. CeOx shells not only serve as radiosensitizer, but also provide the conjugation site for AMP/GMP to form MnO2@CeOx-GAMP (MCG). Upon X-ray irradiation, MCG with SOD-like activity facilitates the conversion of superoxide anions generated by Ce-sensitization into H2O2 within tumor microenvironment (TME). The downstream POD-like activity catalyzes the elevated H2O2 into a profusion of ·OH for producing more damage DNA fragments. TME-responsive decomposed MCG could supply exogenous cGAMP, meanwhile the releasing Mn2+ improve the sensitivity of cyclic GMP-AMP synthase to dsDNA for producing more cGAMP, resulting in the promotion of STING pathway activation.

Functional characterization and therapeutic potential of human umbilical cord blood mononuclear cells

Human umbilical cord blood mononuclear cells (hUCB-MNCs) are a population of cells derived from neonatal cord blood, encompassing various stem cells and immune cells. The unique characteristics of hUCB-MNCs endow them with distinctive multifunctionality, including the promotion of angiogenesis, acceleration of tissue repair, regulation of immune responses, neuroprotection, alleviation of inflammatory reactions, enhancement of antioxidant capacity, reduction of fibrosis processes, and inhibition of apoptosis. These diverse biological properties underscore the significant clinical therapeutic potential of hUCB-MNCs, which are widely applied in the treatment of various diseases. This review aims to summarize the underlying mechanisms responsible for the multifunctional attributes of hUCB-MNCs, elucidating their potential modes of action in disease management and providing novel theoretical insights and practical guidance for their expanded application across different disease domains. By synthesizing current research findings, this review may provide insights into the potential clinical applications of hUCB-MNCs in the fields of regenerative medicine and cell therapy.

Bioactive Decellularized Extracellular Matrix Platform Integrating Multifunctional Nanozymes and Cell-Laden Microgels for Acute Liver Failure Treatment

Mesenchymal stem cell (MSC) therapy has emerged as a promising alternative approach for treating acute liver failure (ALF) while confronting the shortage of low efficiency and poor engraftment within a hostile liver milieu. In this study, we establish a bioactive decellularized extracellular matrix (dECM) platform that incorporates dihydrolipoic acid (DHLA)-protected Pt nanoclusters doped with Cu (PtCu-DHLA) nanozymes and cell-laden microgels. The PtCu-DHLA nanozymes, selected for their versatility, function as antioxidant, anti-inflammatory, pro-proliferative, and pro-angiogenic agents, enhancing ALF alleviation and providing an optimal microenvironment for MSC transplantation. Additionally, a methacrylic anhydride (MA)-modified porcine liver-derived decellularized extracellular matrix (PLdECM) hydrogel (PLdECMMA) has been developed for the construction of microgels via microfluidic devices. Interferon γ (IFNγ) preconditioned MSCs encapsulated in PLdECMMA microgels exhibit enhanced immunomodulating activity and prolonged survival. PtCu-DHLA nanozymes and cell-laden microgels are codelivered by leveraging the PLdECM hydrogel for orthotopic transplantation. The transplanted dECM platform enables an efficient and successful rescue of CCl4-induced ALF by counteracting oxidative stress, suppressing inflammatory storms, and promoting cellular regeneration. Overall, this study highlights a synergistic and reinforced strategy that combines biomimetic nanozymes with MSC therapy, offering significant potential for ALF treatment and broader applications in regenerative medicine.

Oxygen-Bonded Amorphous Transition Metal Dichalcogenides with pH-Responsive Reactive Oxygen Biocatalysis for Combined Antibacterial and Anti-inflammatory Therapies in Diabetic Wound Healing

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-Or) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-Or exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-Or demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-Or serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-Or, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-Or as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

Bioinspired artificial antioxidases for efficient redox homeostasis and maxillofacial bone regeneration

Reconstructing large, inflammatory maxillofacial defects using stem cell-based therapy faces challenges from adverse microenvironments, including high levels of reactive oxygen species (ROS), inadequate oxygen, and intensive inflammation. Here, inspired by the reaction mechanisms of intracellular antioxidant defense systems, we propose the de novo design of an artificial antioxidase using Ru-doped layered double hydroxide (Ru-hydroxide) for efficient redox homeostasis and maxillofacial bone regeneration. Our studies demonstrate that Ru-hydroxide consists hydroxyls-synergistic monoatomic Ru centers, which efficiently react with oxygen species and collaborate with hydroxyls for rapid proton and electron transfer, thus exhibiting efficient, broad-spectrum, and robust ROS scavenging performance. Moreover, Ru-hydroxide can effectively sustain stem cell viability and osteogenic differentiation in elevated ROS environments, modulating the inflammatory microenvironment during bone tissue regeneration in male mice. We believe this Ru-hydroxide development offers a promising avenue for designing antioxidase-like materials to treat various inflammation-associated disorders, including arthritis, diabetic wounds, enteritis, and bone fractures.

An Immunomodulatory Hydrogel Featuring Antibacterial and Reactive Oxygen Species Scavenging Properties for Treating Periodontitis in Diabetes

Periodontal disease is a multifactorial, bacterially induced inflammatory disorder characterized by progressive destruction of periodontal tissues. Additionally, diabetes mellitus exacerbates periodontitis, resulting in expedited resorption of periodontal bone. However, methods such as mechanical debridement, anti-inflammatory medications, and surgical approaches often fail to eradicate local infections and inflammation, complicating the reconstruction of periodontal tissue structures. Consequently, there is an urgent need to devise a novel strategy for managing diabetic periodontal conditions. Here, a multifunctional controlled-release drug delivery system (GOE1) is developed by encapsulating self-assembled nanoparticles (consisting of chlorhexidine acetate and epigallocatechin-3-gallate) into a hydrogel matrix composed of gelatin methacryloyl and oxidized hyaluronic acid. In vitro experiments demonstrate that the GOE1 hydrogel possesses good antimicrobial, antioxidant and anti-inflammatory properties, and transgenic sequence genomics further illustrates that IL-17-producing RAW 264.7 macrophages are critical for mediating M1/M2 macrophage transition and provide favorable immune microenvironment. In addition, in vivo experiments reveal that GOE1 significantly ameliorates periodontal tissue inflammation and reduces the loss of alveolar bone by reducing inflammatory infiltration and collagen destruction. Overall, the GOE1 hydrogel offers a promising therapeutic option for managing diabetic periodontitis.

Heterojunction Nanozyme Hydrogels Containing Cu-O-Zn Bonds with Strong Charge Transfer for Accelerated Diabetic Wound Healing

The complex microenvironment of persistent inflammation and bacterial infection is a major challenge in chronic diabetic wounds. The development of nanozymes capable of efficiently scavenging reactive oxygen species (ROS) is a promising method to promote diabetic wound healing. However, many nanozymes show rather limited antioxidant activity and ROS-dependent antibacterial effects under certain circumstances, further weakening their ability to scavenge ROS. To meet these challenges, electronically regulated bioheterojunction (E-bio-HJ) nanozyme hydrogels derived from metal-organic frameworks (MOFs) were designed and prepared via an interface engineering strategy. Owing to the electron transfer and redistribution effects of the abundant and highly dispersed Cu-O-Zn sites at the heterogeneous interface, the E-bio-HJ nanozymes exhibited catalase (CAT)-like activity with ultrahigh hydrogen peroxide affinity (Km = 25.76 mM) and sustained ROS consumption. In addition, owing to the enhanced interfacial effect of E-bio-HJ and the good biocompatibility and cell adhesion of the methacryloylated gelatin (Gel) hydrogel, the E-bio-HJ gelatin hydrogel (E-bio-HJ/Gel) further reduced inflammation by inducing macrophage transformation to the M2 phenotype, accompanied by excellent antimicrobial properties and enhanced cell migration, angiogenesis, and collagen deposition, which synergistically promoted diabetic wound healing. This highly effective and comprehensive strategy offers a new approach for the rapid healing of diabetic wounds.

Copper-Based Nanoparticles for Effective Treatment Against Sepsis-Induced Lung Injury in Mice Model

Introduction

Lung injury, a common complication of sepsis, arises from elevated reactive oxygen species (ROS), mitochondrial dysfunction, and cell death driven by inflammation. In this study, a novel class of ultrasmall nanoparticles (Cu4.5O USNPs) was developed to address sepsis-induced lung injury (SILI).

Methods

The synthesized nanoparticles were thoroughly characterized to assess their properties. In vitro experiments were conducted to determine the biologically effective concentration and elucidate the anti-inflammatory mechanism of action. These findings were further supported by in vivo studies, showcasing the material's efficacy in mitigating SILI.

Results

The Cu4.5O USNPs demonstrated remarkable scavenging capabilities for hydrogen peroxide (H2O2), superoxide anions (O2 -), and hydroxyl radicals (·OH), attributed to their catalase (CAT)- and superoxide dismutase (SOD)-like activities. Additionally, the nanoparticles exhibited strong anti-inflammatory effects, preserved mitochondrial homeostasis through potent ROS scavenging, and significantly reduced cell death. In vivo studies on mice further validated their protective role against SILI.

The conclusion

This study highlights the therapeutic potential of Cu4.5O USNPs in treating sepsis-induced lung injury by effectively scavenging ROS and reducing cell death. These findings provide compelling evidence for the future use of copper-based nanoparticles as antioxidant therapeutics.

Magnetic soft microrobots for erectile dysfunction therapy

Erectile dysfunction (ED) is a major threat to male fertility and quality of life, and mesenchymal stromal cells (MSCs) are a promising therapeutic option. However, therapeutic outcomes are compromised by low MSC retention and survival rates in corpus cavernosum tissue. Here, we developed an innovative magnetic soft microrobot comprising an ultrasoft hydrogel microsphere embedded with a magnetic nanoparticle chain for MSC delivery. This design also features phenylboronic acid groups for scavenging reactive oxygen species (ROS). With a Young's modulus of less than 1 kPa, the ultrasoft microrobot adapts its shape within narrow blood vessels, ensuring a uniform distribution of MSCs within the corpus cavernosum. Our findings showed that compared with traditional MSC injections, the MSC delivery microrobot (MSC-Rob) significantly enhanced MSC retention and survival. In both rat and beagle ED models, MSC-Rob treatment accelerated the repair of corpus cavernosum tissue and restored erectile function. Single-cell RNA sequencing (scRNA-seq) revealed that MSC-Rob treatment facilitates nerve and blood vessel regeneration in the corpus cavernosum by increasing the presence of regenerative macrophages. Overall, our MSC-Rob not only advances the clinical application of MSCs for ED therapy but also broadens the scope of microrobots for other cell therapies.

Electron-donable heterojunctions with synergetic Ru-Cu pair sites for biocatalytic microenvironment modulations in inflammatory mandible defects

The clinical treatments of maxillofacial bone defects pose significant challenges due to complex microenvironments, including severe inflammation, high levels of reactive oxygen species (ROS), and potential bacterial infection. Herein, we propose the de novo design of an efficient, versatile, and precise electron-donable heterojunction with synergetic Ru-Cu pair sites (Ru-Cu/EDHJ) for superior biocatalytic regeneration of inflammatory mandible defects and pH-controlled antibacterial therapies. Our studies demonstrate that the unique structure of Ru-Cu/EDHJ enhances the electron density of Ru atoms and optimizes the binding strength of oxygen species, thus improving enzyme-like catalytic performance. Strikingly, this biocompatible Ru-Cu/EDHJ can efficiently switch between ROS scavenging in neutral media and ROS generation in acidic media, thus simultaneously exhibiting superior repair functions and bioadaptive antibacterial properties in treating mandible defects in male mice. We believe synthesizing such biocatalytic heterojunctions with exceptional enzyme-like capabilities will offer a promising pathway for engineering ROS biocatalytic materials to treat trauma, tumors, or infection-caused maxillofacial bone defects.

Constructing Electron-Rich Ru Clusters on Non-Stoichiometric Copper Hydroxide for Superior Biocatalytic ROS Scavenging to Treat Inflammatory Spinal Cord Injury

Traumatic spinal cord injury (SCI) represents a complex neuropathological challenge that significantly impacts the well-being of affected individuals. The quest for efficacious antioxidant and anti-inflammatory therapies is both a compelling necessity and a formidable challenge. Here, in this work, the innovative synthesis of electron-rich Ru clusters on non-stoichiometric copper hydroxide that contain oxygen vacancy defects (Ru/def-Cu(OH)2), which can function as a biocatalytic reactive oxygen species (ROS) scavenger for efficiently suppressing the inflammatory cascade reactions and modulating the endogenous microenvironments in SCI, is introduced. The studies reveal that the unique oxygen vacancies promote electron redistribution and amplify electron accumulation at Ru clusters, thus enhancing the catalytic activity of Ru/def-Cu(OH)2 in multielectron reactions involving oxygen-containing intermediates. These advancements endow the Ru/def-Cu(OH)2 with the capacity to mitigate ROS-mediated neuronal death and to foster a reparative microenvironment by dampening inflammatory macrophage responses, meanwhile concurrently stimulating the activity of neural stem cells, anti-inflammatory macrophages, and oligodendrocytes. Consequently, this results in a robust reparative effect on traumatic SCI. It is posited that the synthesized Ru/def-Cu(OH)2 exhibits unprecedented biocatalytic properties, offering a promising strategy to develop ROS-scavenging and anti-inflammatory materials for the management of traumatic SCI and a spectrum of other diseases associated with oxidative stress.

Salvaging myocardial infarction with nanoenzyme-loaded hydrogels: Targeted scavenging of mitochondrial reactive oxygen species

Myocardial infarction resulting from coronary artery atherosclerosis is the leading cause of heart failure, which represents a significant global health burden. The limitations of conventional pharmacologic thrombolysis and flow reperfusion procedures highlight the urgent need for new therapeutic strategies to effectively treat myocardial infarction. In this study, we present a novel biomimetic approach that integrates polyphenols and metal nanoenzymes, inspired by the structure of pomegranates. We developed tannic acid-coated Mn-Co3O4 (MCT) nanoparticles in combination with an injectable collagen hydrogel for the effective treatment of myocardial infarction. The hydrogel enhanced the infarct microenvironment, while the slow-released MCT targets mitochondria to inhibit the post-infarction surge of reactive oxygen species, providing anti-apoptotic and anti-inflammatory effects. RNA sequencing revealed the potential of hydrogels to serve as an interventional mechanism during the post-infarction inflammatory phase. Notably, we found that the hydrogel, when combined with the nanopomegranate-based therapy, significantly improves adverse ventricular remodeling and restores cardiac function in early infarction management. The MCT hydrogel leverages the unique benefits of both MCT nanopomegranates and collagen, demonstrating a synergistic effect. This approach provides a promising example of the potential cooperation between nanomimetic structures and natural biomaterials in therapeutic applications.

Bacteriophage-like Nanobiocatalysts with Spiky Topography and Dual-Atom Sites for Treating Drug-Resistant Bacteria

Overuse of antibiotics leads to the proliferation of drug-resistant bacterial strains, worsening global morbidity, and mortality rates. Bioinspired nanomaterials present a promising avenue for developing nonantibiotic strategies against drug-resistant bacteria. Here, we engineer a bacteriophage-inspired artificial nanobiocatalyst via nonstoichiometric W18O49 that features a spiky topography and synergistic dual-atom sites for combating drug-resistant bacterial infection. Benefiting from the strong interaction within the synergistic Fe-O-Mo sites, the synthesized spiky artificial nanobiocatalyst exhibits superior reactive oxygen species (ROS)-catalytic activity, attributed to the regulated adsorption affinity between the reaction intermediates and catalytic sites. The experimental and theoretical investigations demonstrate that the bioinspired biocatalyst can effectively capture and kill bacteria through its spiky morphology and potent ROS-catalytic activity, which can enable a significant reduction in bacterial viability through downregulating genes associated with biosynthesis, cellular maintenance, and respiration. In vivo experiments demonstrate that the spiky artificial biocatalyst accelerates the reconstruction of drug-resistant bacteria-infected skin wounds in rabbits, exhibiting efficacy comparable to that of vancomycin. It is expected that this bioinspired study on spiky artificial nanobiocatalysts offers a straightforward path to facilitate the development of both bionic and nonantibiotic disinfection strategies.

Infectious and Inflammatory Microenvironment Self-Adaptive Artificial Peroxisomes with Synergetic Co-Ru Pair Centers for Programmed Diabetic Ulcer Therapy

Complex microenvironments with bacterial infection, persistent inflammation, and impaired angiogenesis are the major challenges in chronic refractory diabetic ulcers. To address this challenge, a comprehensive strategy with highly effective and integrated antimicrobial, anti-inflammatory, and accelerated angiogenesis will offer a new pathway to the rapid healing of infected diabetic ulcers. Here, inspired by the tunable reactive oxygen species (ROS) regulation properties of natural peroxisomes, this work reports the design of infectious and inflammatory microenvironments self-adaptive artificial peroxisomes with synergetic Co-Ru pair centers (APCR) for programmed diabetic ulcer therapy. Benefiting from the synergistic Co and Ru atoms, the APCR can simultaneously achieve ROS production and metabolic inhibition for bacterial sterilization in the infectious microenvironment. After disinfection, the APCR can also eliminate ROS to alleviate oxidative stress in the inflammatory microenvironment and promote wound regeneration. The data demonstrate that the APCR combines highly effective antibacterial, anti-inflammatory, and provascular regeneration capabilities, making it an efficient and safe nanomedicine for treating infectious and inflammatory diabetic foot ulcers via a programmed microenvironment self-adaptive treatment pathway. This work expects that synthesizing artificial peroxisomes with microenvironments self-adaptive and bifunctional enzyme-like ROS regulation properties will provide a promising path to construct ROS catalytic materials for treating complex diabetic ulcers, trauma, or other infection-caused diseases.

Nanorepair medicine for treatment of organ injury

Organ injuries, such as acute kidney injury, ischemic stroke, and spinal cord injury, often result in complications that can be life-threatening or even fatal. Recently, many nanomaterials have emerged as promising agents for repairing various organ injuries. In this review, we present the important developments in the field of nanomaterial-based repair medicine, herein referred to as 'nanorepair medicine'. We first introduce the disease characteristics associated with different types of organ injuries and highlight key examples of relevant nanorepair medicine. We then provide a summary of existing strategies in nanorepair medicine, including organ-targeting methodologies and potential countermeasures against exogenous and endogenous pathologic risk factors. Finally, we offer our perspectives on current challenges and future expectations for the advancement of nanomedicine designed for organ injury repair.

Recent Advances in Nanomaterials for Modulation of Stem Cell Differentiation and Its Therapeutic Applications

Challenges in directed differentiation and survival limit the clinical use of stem cells despite their promising therapeutic potential in regenerative medicine. Nanotechnology has emerged as a powerful tool to address these challenges and enable precise control over stem cell fate. In particular, nanomaterials can mimic an extracellular matrix and provide specific cues to guide stem cell differentiation and proliferation in the field of nanotechnology. For instance, recent studies have demonstrated that nanostructured surfaces and scaffolds can enhance stem cell lineage commitment modulated by intracellular regulation and external stimulation, such as reactive oxygen species (ROS) scavenging, autophagy, or electrical stimulation. Furthermore, nanoframework-based and upconversion nanoparticles can be used to deliver bioactive molecules, growth factors, and genetic materials to facilitate stem cell differentiation and tissue regeneration. The increasing use of nanostructures in stem cell research has led to the development of new therapeutic approaches. Therefore, this review provides an overview of recent advances in nanomaterials for modulating stem cell differentiation, including metal-, carbon-, and peptide-based strategies. In addition, we highlight the potential of these nano-enabled technologies for clinical applications of stem cell therapy by focusing on improving the differentiation efficiency and therapeutics. We believe that this review will inspire researchers to intensify their efforts and deepen their understanding, thereby accelerating the development of stem cell differentiation modulation, therapeutic applications in the pharmaceutical industry, and stem cell therapeutics.

Self-Assembled DNA Composite-Engineered Mesenchymal Stem Cells for Improved Skin-Wound Repair

The direct use of mesenchymal stem cells (MSCs) as therapeutics for skin injuries is a promising approach, yet it still faces several obstacles, including limited adhesion, retention, and engraftment of stem cells in the wound area, as well as impaired regenerative and healing functions. Here, DNA-based self-assembled composites are reported that can aid the adhesion of MSCs in skin wounds, enhance MSC viability, and accelerate wound closure and re-epithelialization. Rolling-circle amplification (RCA)-derived DNA flowers, equipped with multiple copies of cyclic Arg-Gly-Asp (cRGD) peptides and anti-von Willebrand factor (vWF) aptamers, act as robust scavengers of reactive oxygen species (ROS) and enable synergistic recognition and adhesion to stem cells and damaged vascular endothelial cells. These DNA structure-aided stem cells are retained at localized wound sites, maintain repair function, and promote angiogenesis and growth factor secretion. In both normal and diabetes-prone db/db mice models with excisional skin injuries, facile topical administration of DNA flower-MSCs elicits rapid blood vessel formation and enhances the sealing of the wound edges in a single dose. DNA composite-engineered stem cells warrant further exploration as a new strategy for the treatment of skin and tissue damage.

Self-assembled copper-based nanoparticles for enzyme catalysis-enhanced chemodynamic/photodynamic/antiangiogenic tritherapy against hepatocellular carcinoma

As an emerging cancer treatment strategy, reactive oxygen species-based tumor catalytic therapies face enormous challenges due to hypoxia and the overexpression of glutathione (GSH) in the tumor microenvironment. Herein, a self-assembled copper-based nanoplatform, TCCHA, was designed for enzyme-like catalysis-enhanced chemodynamic/photodynamic/antiangiogenic tritherapy against hepatocellular carcinoma. TCCHA was fabricated from Cu2+, 3,3'-dithiobis (propionohydrazide), and photosensitizer chlorine e6 via a facile one-pot self-assembly strategy, after which an aldehyde hyaluronic acid was coated, followed by loading of the antivascular drug AL3818. The obtained TCCHA nanoparticles exhibited pH/GSH dual-responsive drug release behaviors and multienzymatic activities, including Fenton, glutathione peroxidase-, and catalase-like activities. TCCHA, a redox homeostasis disruptor, promotes ⋅OH generation and GSH depletion, thus increasing the efficacy of chemodynamic therapy. TCCHA, which has catalase-like activity, can also reinforce the efficacy of photodynamic therapy by amplifying O2 production. In vivo, TCCHA efficiently inhibited tumor angiogenesis and suppressed tumor growth without apparent systemic toxicity. Overall, this study presents a facile strategy for the preparation of multienzyme-like nanoparticles, and TCCHA nanoparticles display great potential for enzyme catalysis-enhanced chemodynamic/photodynamic/antiangiogenic triple therapy against cancer.

Glucose Oxidase Energized Osmium with Dual-Active Centers and Triple Enzyme Activities for Infected Diabetic Wound Management

Diabetic wounds are susceptible to bacterial infections, largely linked to high blood glucose levels (hyperglycemia). To treat such wounds, enzymes like glucose oxidase (GOx) can be combined with nanozymes (nanomaterials mimic enzymes) to use glucose effectively for purposes. However, there is still room for improvement in these systems, particularly in terms of process simplification, enzyme activity regulation, and treatment effects. Herein, the approach utilizes GOx to directly facilitate the biomineralized growth of osmium (Os) nanozyme (GOx-OsNCs), leading to dual-active centers and remarkable triple enzyme activities. Initially, GOx-OsNCs use vicinal dual-active centers, enabling a self-cascaded mechanism that significantly enhances glucose sensing performance compared to step-by-step reactions, surpassing the capabilities of other metal sources such as gold and platinum. In addition, GOx-OsNCs are integrated into a glucose-sensing gel, enabling instantaneous visual feedback. In the treatment of infected diabetic wounds, GOx-OsNCs exhibit multifaceted benefits by lowering blood glucose levels and exhibiting antibacterial properties through the generation of hydroxyl free radicals, thereby expediting healing by fostering a favorable microenvironment. Furthermore, the catalase-like activity of GOx-OsNCs aids in reducing oxidative stress, inflammation, and hypoxia, culminating in improved healing outcomes. Overall, this synergistic enzyme-nanozyme blend is user-friendly and holds considerable promise for diverse applications.

Multifunctional PtCuTe Nanosheets with Strong ROS Scavenging and ROS-Independent Antibacterial Properties Promote Diabetic Wound Healing

Nanozymes, as one of the most efficient reactive oxygen species (ROS)-scavenging biomaterials, are receiving wide attention in promoting diabetic wound healing. Despite recent attempts at improving the catalytic efficiency of Pt-based nanozymes (e.g., PtCu, one of the best systems), they still display quite limited ROS scavenging capacity and ROS-dependent antibacterial effects on bacteria or immunocytes, which leads to uncontrolled and poor diabetic wound healing. Hence, a new class of multifunctional PtCuTe nanosheets with excellent catalytic, ROS-independent antibacterial, proangiogenic, anti-inflammatory, and immuno-modulatory properties for boosting the diabetic wound healing, is reported. The PtCuTe nanosheets show stronger ROS scavenging capacity and better antibacterial effects than PtCu. It is also revealed that the PtCuTe can enhance vascular tube formation, stimulate macrophage polarization toward the M2 phenotype and improve fibroblast mobility, outperforming conventional PtCu. Moreover, PtCuTe promotes crosstalk between different cell types to form a positive feedback loop. Consequently, PtCuTe stimulates a proregenerative environment with relevant cell populations to ensure normal tissue repair. Utilizing a diabetic mouse model, it is demonstrated that PtCuTe significantly facilitated the regeneration of highly vascularized skin, with the percentage of wound closure being over 90% on the 8th day, which is the best among the reported comparable multifunctional biomaterials.

Spiky Artificial Peroxidases with V-O-Fe Pair Sites for Combating Antibiotic-Resistant Pathogens

With the sharp rise of antibiotic-resistant pathogens worldwide, it is of enormous importance to create new strategies for combating pathogenic bacteria. Here, we create an iron oxide-based spiky artificial peroxidase (POD) with V-O-Fe pair sites (V-Fe2 O3 ) for combating methicillin-resistant Staphylococcus aureus (MRSA). The experimental studies and theoretical calculations demonstrate that the V-Fe2 O3 can achieve the localized "capture and killing" bifunction from the spiky morphology and massive reactive oxygen species (ROS) production. The V-Fe2 O3 can reach nearly 100 % bacterial inhibition over a long period by efficiently oxidizing the lipid membrane. Our wound disinfection results identify that the V-Fe2 O3 can not only efficiently eliminate MRSA and their biofilm but also accelerate wound recovery without causing noticeable inflammation and toxicity. This work offers essential insights into the critical roles of V-O-Fe pair sites and localized "capture and killing" in biocatalytic disinfection and provides a promising pathway for the de novo design of efficient artificial peroxidases.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Piezoelectric Effect Modulates Nanozyme Activity: Underlying Mechanism and Practical Application

Nanozyme activity relies on surface electron transfer processes. Notably, the piezoelectric effect plays a vital role in influencing nanozyme activity by generating positive and negative charges on piezoelectric materials' surfaces. This article comprehensively reviews the potential mechanisms and practical applications of regulating nanozyme activity through the piezoelectric effect. The article first elucidates how the piezoelectric effect enables nanozymes to exhibit catalytic activity. It is highlighted that the positive and negative charges produced by this effect directly participate in redox reactions, leading to the conversion of materials from an inactive to an active state. Moreover, the piezoelectric field generated can enhance nanozyme activity by accelerating electron transfer rates or reducing binding energy between nanozymes and substrates. Practical applications of piezoelectric nanozymes are explored in the subsequent section, including water pollutant degradation, bacterial disinfection, biological detection, and tumor therapy, which demonstrate the versatile potentials of the piezoelectric effect in nanozyme applications. The review concludes by emphasizing the need for further research into the catalytic mechanisms of piezoelectric nanozymes, suggesting expanding the scope of catalytic types and exploring new application areas. Furthermore, the promising direction of synergistic catalytic therapy is discussed as an inspiring avenue for future research.

Reactive oxygen nanobiocatalysts: activity-mechanism disclosures, catalytic center evolutions, and changing states

Benefiting from low costs, structural diversities, tunable catalytic activities, feasible modifications, and high stability compared to the natural enzymes, reactive oxygen nanobiocatalysts (RONBCs) have become dominant materials in catalyzing and mediating reactive oxygen species (ROS) for diverse biomedical and biological applications. Decoding the catalytic mechanism and structure-reactivity relationship of RONBCs is critical to guide their future developments. Here, this timely review comprehensively summarizes the recent breakthroughs and future trends in creating and decoding RONBCs. First, the fundamental classification, activity, detection method, and reaction mechanism for biocatalytic ROS generation and elimination have been systematically disclosed. Then, the merits, modulation strategies, structure evolutions, and state-of-art characterisation techniques for designing RONBCs have been briefly outlined. Thereafter, we thoroughly discuss different RONBCs based on the reported major material species, including metal compounds, carbon nanostructures, and organic networks. In particular, we offer particular insights into the coordination microenvironments, bond interactions, reaction pathways, and performance comparisons to disclose the structure-reactivity relationships and mechanisms. In the end, the future challenge and perspectives for RONBCs are also carefully summarised. We envision that this review will provide a comprehensive understanding and guidance for designing ROS-catalytic materials and stimulate the wide utilisation of RONBCs in diverse biomedical and biological applications.

An Extracellular Vesicle-Cloaked Multifaceted Biocatalyst for Ultrasound-Augmented Tendon Matrix Reconstruction and Immune Microenvironment Regulation

The healing of tendon injury is often hindered by peritendinous adhesion and poor regeneration caused by the accumulation of reactive oxygen species (ROS), development of inflammatory responses, and the deposition of type-III collagen. Herein, an extracellular vesicles (EVs)-cloaked enzymatic nanohybrid (ENEV) was constructed to serve as a multifaceted biocatalyst for ultrasound (US)-augmented tendon matrix reconstruction and immune microenvironment regulation. The ENEV-based biocatalyst exhibits integrated merits for treating tendon injury, including the efficient catalase-mimetic scavenging of ROS in the injured tissue, sustainable release of Zn2+ ions, cellular uptake augmented by US, and immunoregulation induced by EVs. Our study suggests that ENEVs can promote tenocyte proliferation and type-I collagen synthesis at an early stage by protecting tenocytes from ROS attack. The ENEVs also prompted efficient immune regulation, as the polarization of macrophages (Mφ) was reversed from M1φ to M2φ. In a rat Achilles tendon defect model, the ENEVs combined with US treatment significantly promoted functional recovery and matrix reconstruction, restored tendon morphology, suppressed intratendinous scarring, and inhibited peritendinous adhesion. Overall, this study offers an efficient nanomedicine for US-augmented tendon regeneration with improved healing outcomes and provides an alternative strategy to design multifaceted artificial biocatalysts for synergetic tissue regenerative therapies.

Arthritic Microenvironment-Dictated Fate Decisions for Stem Cells in Cartilage Repair

The microenvironment and stem cell fate guidance of post-traumatic articular cartilage regeneration is primarily the focus of cartilage tissue engineering. In articular cartilage, stem cells are characterized by overlapping lineages and uneven effectiveness. Within the first 12 weeks after trauma, the articular inflammatory microenvironment (AIME) plays a decisive role in determining the fate of stem cells and cartilage. The development of fibrocartilage and osteophyte hyperplasia is an adverse outcome of chronic inflammation, which results from an imbalance in the AIME during the cartilage tissue repair process. In this review, the sources for the different types of stem cells and their fate are summarized. The main pathophysiological events that occur within the AIME as well as their protagonists are also discussed. Additionally, regulatory strategies that may guide the fate of stem cells within the AIME are proposed. Finally, strategies that provide insight into AIME pathophysiology are discussed and the design of new materials that match the post-traumatic progress of AIME pathophysiology in a spatial and temporal manner is guided. Thus, by regulating an appropriately modified inflammatory microenvironment, efficient stem cell-mediated tissue repair may be achieved.

Cascade and Ultrafast Artificial Antioxidases Alleviate Inflammation and Bone Resorption in Periodontitis

Periodontitis, one of the most common, challenging, and rapidly expanding oral diseases, is an oxidative stress-related disease caused by excessive reactive oxygen species (ROS) production. Developing ROS-scavenging materials to regulate the periodontium microenvironments is essential for treating periodontitis. Here, we report on creating cobalt oxide-supported Ir (CoO-Ir) as a cascade and ultrafast artificial antioxidase to alleviate local tissue inflammation and bone resorption in periodontitis. It is demonstrated that the Ir nanoclusters are uniformly supported on the CoO lattice, and there is stable chemical coupling and strong charge transfer from Co to Ir sites. Benefiting from its structural advantages, CoO-Ir presents cascade and ultrafast superoxide dismutase-catalase-like catalytic activities. Notably, it displays distinctly increased Vmax (76.249 mg L-1 min-1) and turnover number (2.736 s-1) when eliminating H2O2, which surpasses most of the by-far-reported artificial enzymes. Consequently, the CoO-Ir not only provides efficient cellular protection from ROS attack but also promotes osteogenetic differentiation in vitro. Furthermore, CoO-Ir can efficiently combat periodontitis by inhibiting inflammation-induced tissue destruction and promoting osteogenic regeneration. We believe that this report will shed meaningful light on creating cascade and ultrafast artificial antioxidases and offer an effective strategy to combat tissue inflammation and osteogenic resorption in oxidative stress-related diseases.

Microenvironment Restruction of Emerging 2D Materials and their Roles in Therapeutic and Diagnostic Nano-Bio-Platforms

Engineering advanced therapeutic and diagnostic nano-bio-platforms (NBPFs) have emerged as rapidly-developed pathways against a wide range of challenges in antitumor, antipathogen, tissue regeneration, bioimaging, and biosensing applications. Emerged 2D materials have attracted extensive scientific interest as fundamental building blocks or nanostructures among material scientists, chemists, biologists, and doctors due to their advantageous physicochemical and biological properties. This timely review provides a comprehensive summary of creating advanced NBPFs via emerging 2D materials (2D-NBPFs) with unique insights into the corresponding molecularly restructured microenvironments and biofunctionalities. First, it is focused on an up-to-date overview of the synthetic strategies for designing 2D-NBPFs with a cross-comparison of their advantages and disadvantages. After that, the recent key achievements are summarized in tuning the biofunctionalities of 2D-NBPFs via molecularly programmed microenvironments, including physiological stability, biocompatibility, bio-adhesiveness, specific binding to pathogens, broad-spectrum pathogen inhibitors, stimuli-responsive systems, and enzyme-mimetics. Moreover, the representative therapeutic and diagnostic applications of 2D-NBPFs are also discussed with detailed disclosure of their critical design principles and parameters. Finally, current challenges and future research directions are also discussed. Overall, this review will provide cutting-edge and multidisciplinary guidance for accelerating future developments and therapeutic/diagnostic applications of 2D-NBPFs.

Immunomodulation for Tissue Repair and Regeneration

Various immune cells participate in repair and regeneration following tissue injury or damage, orchestrating tissue inflammation and regeneration processes. A deeper understanding of the immune system's involvement in tissue repair and regeneration is critical for the development of successful reparatory and regenerative strategies. Here we review recent technologies that facilitate cell-based and biomaterial-based modulation of the immune systems for tissue repair and regeneration. First, we summarize the roles of various types of immune cells in tissue repair. Second, we review the principle, examples, and limitations of regulatory T (Treg) cell-based therapy, a representative cell-based immunotherapy. Finally, we discuss biomaterial-based immunotherapy strategies that aim to modulate immune cells using various biomaterials for tissue repair and regeneration.

Electron transfer-based antioxidant nanozymes: Emerging therapeutics for inflammatory diseases

Inflammatory diseases are usually featured with relatively high level of reactive oxygen species (ROS). The excess ROS facilitate the polarization of microphages into proinflammatory M1 phenotype, and cause DNA damage, protein carbonylation, and lipid peroxidation, resulting in further deterioration of inflammatory diseases. Therefore, alleviating oxidative stress by ROS scavenging has been an effective strategy for reversing inflammation. Inspired by the natural antioxidant enzymes, electron transfer-based artificial antioxidant nanozymes have been emerging therapeutics for the treatment of inflammatory diseases. The present review starts with the basic knowledge of ROS and diseases, followed by summarizing the possible active centers for the preparation of antioxidant nanozymes. The strategies for the design of antioxidant nanozymes on the purpose of higher catalytic activity are provided, and the applications of the developed antioxidant nanozymes on the therapy of inflammatory diseases are discussed. A perspective is included for the design and applications of artificial antioxidant nanozymes in biomedicine as well.

Cobaltosic oxide-polyethylene glycol-triphenylphosphine nanoparticles ameliorate the acute-to-chronic kidney disease transition by inducing BNIP3-mediated mitophagy

Accumulating evidence highlights mitochondrial dysfunction as a crucial factor in the pathogenesis of acute kidney injury (AKI); thus, novel therapeutic strategies maintaining mitochondrial homeostasis are highly anticipated. Recent studies have shown that cobaltosic oxide has peroxidase-like catalytic activities, although its role and mechanism remain elusive in AKI. In the present study, we synthesized and identified cobaltosic oxide-polyethylene glycol-triphenylphosphine (COPT) nanoparticles by conjugating cobaltosic oxide with polyethylene glycol and triphenylphosphine, to improve its biocompatibility and mitochondria-targeting property. We found that COPT preferentially accumulated in the kidney proximal tubule cells, and significantly alleviated ischemic AKI in mouse models and gentamicin induced-AKI in the zebrafish model. COPT also inhibited the transition from AKI to chronic kidney disease (CKD), with few side effects. Further studies demonstrated that COPT localized in the mitochondria, and ameliorated hypoxia-reoxygenation-mediated mitochondrial damage through enhancing mitophagy in vitro and in vivo. Mechanistically, COPT dose-dependently induced the expression of Bcl-2/adenovirus E1B 19-kDa interacting protein (BNIP3), while knockdown of BNIP3 attenuated COPT-induced mitophagic flux and mitochondrial protection. Thus, our findings suggest that COPT nanoparticles ameliorate AKI and its progression to CKD through inducing BNIP3-mediated mitophagy, indicating that COPT may serve as a promising mitochondria-targeting therapeutic agent against AKI.

Amorphizing Metal Selenides-Based ROS Biocatalysts at Surface Nanolayer toward Ultrafast Inflammatory Diabetic Wound Healing

The microenvironments with high reactive-oxygen-species (ROS) levels, inflammatory responses, and oxidative-stress effects in diabetic ulcer wounds, leading to poor proliferation and differentiation of stem cells, severely inhibit their efficient healing. Here, to overcome the unbalanced multielectron reactions in ROS catalysis, we develop a cobalt selenide-based biocatalyst with an amorphous Ru@CoSe nanolayer for ultrafast and broad-spectrum catalytic ROS-elimination. Owing to the enriched electrons and more unoccupied orbitals of Ru atoms, the amorphous Ru@CoSe nanolayer-equipped biocatalyst displays excellent catalase-like kinetics (maximal reaction velocity, 23.05 μM s^-1; turnover number, 2.00 s^-1), which exceeds most of the currently reported metal compounds. The theoretical studies show that Ru atoms act as "regulators" to tune the electronic state of the Co sites and modulate the interaction of oxygen intermediates, thus improving the reversible redox properties of active sites. Consequently, the Ru@CoSe can efficiently rescue the proliferation of mesenchymal stem cells and maintain their angiogenic potential in the oxidative stress environment. In vivo experiments reveal the superior ROS-elimination ability of Ru@CoSe on the inflammatory diabetic wound. This study offers an effective nanomedicine for catalytic ROS-scavenging and ultrafast healing of inflammatory wounds and also provides a strategy to design biocatalytic metal compounds via bringing amorphous catalytic structures.

Redox Modulatory Cu(II)-Baicalein Microflowers Prepared in One Step Effectively Promote Therapeutic Angiogenesis in Diabetic Mice

Reactive oxygen species (ROS) have been implicated in multiple cellular processes, and an imbalance in redox homeostasis gives rise to diseases, therefore, reestablishing redox homeostasis is a way to cure. Here, copper-based metal-organic networks (Cu-MON) are generated by one-step reaction using anti-inflammatory and antioxidant baicalein as organic ligand and pro-angiogenic copper as metal ions. Phosphate buffered saline is required for triggering Cu-MON formation, and baicalein regulates the morphology and particle size of Cu-MON. Cu-MON are composed of Cu-baicalein complexes (82.08 wt%) and Cu₃ (PO₄ )₂ ·3H₂ O (17.92 wt%), thus exhibit a variable catalase-like activity against different H₂ O₂ levels due to the reversible change between Cu²⁺ /Cu¹⁺ /Cu⁰ species. Intramuscular injection of Cu-MON significantly increases blood flow of ischemic limb in diabetic mice, enhances the relative activities of redox-related enzymes in ischemic muscle, thus effectively ameliorating the oxidative damage. Taken together, through moderate and dynamic "precise homeostasis regulation of cells," Cu-MON can be an efficient therapeutic strategy for peripheral arterial disease with diabetic complications.

Bone regeneration strategies based on organelle homeostasis of mesenchymal stem cells

The organelle modulation has emerged as a crucial contributor to the organismal homeostasis. The mesenchymal stem cells (MSCs), with their putative functions in maintaining the regeneration ability of adult tissues, have been identified as a major driver to underlie skeletal health. Bone is a structural and endocrine organ, in which the organelle regulation on mesenchymal stem cells (MSCs) function has most been discovered recently. Furthermore, potential treatments to control bone regeneration are developing using organelle-targeted techniques based on manipulating MSCs osteogenesis. In this review, we summarize the most current understanding of organelle regulation on MSCs in bone homeostasis, and to outline mechanistic insights as well as organelle-targeted approaches for accelerated bone regeneration.