A Functionalized Octahedral Palladium Nanozyme as a Radical Scavenger for Ameliorating Alzheimer's Disease

Reprogramming Retinal Microglia Polarization by Efferocytosis-Mimicking Nanoparticles for Ameliorating Diabetic Retinopathy

Diabetic retinopathy (DR), as the most common microvascular complication of diabetes, seriously threatens the vision of diabetic patients. As the resident phagocytes of the retina, microglia participate in inflammation, neovascularization, and neurodegeneration of DR. Herein, apoptotic retinal cell membrane-coated, rapamycin-loaded mesoporous Prussian blue NPs as immunomodulators for ameliorating DR by modulating microglial polarization are reported. The apoM@mPB@Ra NPs exhibited favorable stability and biocompatibility and achieved active targeted delivery due to the specific recognition between "eat me" signal expressed on apoptotic membrane and microglia. In an LPS-induced cellular inflammation model, apoM@mPB@Ra NPs effectively promoted microglial polarization toward the anti-inflammatory phenotype (M2) by scavenging intracellular reactive oxygen species (ROS) combined with affecting the mTOR signaling pathway, leading to downregulation of pro-inflammatory cytokines IL-6 and TNF-α. Meanwhile, owing to the multienzyme-like activities of mPB in nanoparticles, apoM@mPB@Ra NPs obviously alleviated cellular hypoxia, thereby decreasing the expression of VEGF. Notably, in a mouse model of DR, intravitreally injected apoM@mPB@Ra NPs significantly improved the severity of the abnormal retinal vascular network and inflammatory microenvironment of retinopathy by down-regulating the expression of HIF-1α, VEGF, and inflammatory-related cytokines. Collectively, these findings demonstrate that apoM@mPB@Ra NPs provide a promising and effective approach for the treatment of DR.

Nanozymes: Innovative Therapeutics in the Battle Against Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), represent a significant challenge to global health due to their progressive nature and the absence of curative treatments. These disorders are characterized by oxidative stress, protein misfolding, and neuroinflammation, which collectively contribute to neuronal damage and death. Recent advancements in nanotechnology have introduced nanozymes-engineered nanomaterials that mimic enzyme-like activities-as promising therapeutic agents. This review explores the multifaceted roles of nanozymes in combating oxidative stress and inflammation in neurodegenerative conditions. By harnessing their potent antioxidant properties, nanozymes can effectively scavenge reactive oxygen species (ROS) and restore redox balance, thereby protecting neuronal function. Their ability to modify surface properties enhances targeted delivery and biocompatibility, making them suitable for various biomedical applications. In this review, we highlight recent findings on the design, functionality, and therapeutic potential of nanozymes, emphasizing their dual role in addressing oxidative stress and pathological features such as protein aggregation. This synthesis of current research underscores the innovative potential of nanozymes as a proactive therapeutic strategy to halt disease progression and improve patient outcomes in neurodegenerative disorders.

Intervening with nanozymes in aging-related diseases: Strategies for restoring mitochondrial function

The decline in mitochondrial function has been identified as one of the central pathological mechanisms underlying a variety of aging-related diseases. Nanozymes are nanomaterials with intrinsic enzyme-like properties and are important alternatives to natural enzymes. As emerging biocatalysts, nanozymes exhibit significant potential in mimicking the activity of natural enzymes, enhancing mitochondrial function, and offering novel therapeutic strategies for aging-related conditions. This review provides an overview of various approaches to modulate the catalytic activity of nanozymes, considering factors such as particle size, shape, surface modifications, and constituent elements. It then examines the role of nanozymes in mitigating aging-related diseases by preserving mitochondrial health, with a particular focus on their ability to regulate three critical aspects: mitochondrial energy metabolism, quality control, and antioxidant capacity. By improving mitochondrial energy generation, supporting mitochondrial integrity, and eliminating excess reactive oxygen species (ROS), nanozymes offer new therapeutic possibilities for neurodegenerative diseases, bone-related disorders, and diabetes. Finally, this article discusses the major challenges faced in this field, including issues such as the scalability, biocompatibility, and targeting ability of nanozymes. It also emphasizes that future research should focus on enhancing clinical translation to ensure that nanozymes can play an effective role in practical therapeutic applications.

Glutathione-protected Au22 Nanoclusters Ameliorates Hypoxic-Ischemic Brain Damage in Neonatal Rats via Sirt3/SOD2 Signaling Pathway

Hypoxic-ischemic brain damage (HIBD) arises from perinatal hypoxia, a leading cause of neonatal mortality during the perinatal period, as well as subsequent disabilities beyond the neonatal stage. While there is currently no unified and comprehensive treatment approach for hypoxic-ischemic encephalopathy (HIE), hypothermia therapy represents the only recognized clinical intervention. Nevertheless, the efficacy of hypothermia therapy remains limited. Recently, atomically precise metal nanoclusters (NCs), an emerging class of nanomaterials, has displayed promising potential in biomedical field. This study aimed to assess whether glutathione-protected Au22 nanoclusters (GSH-Au22 NCs) could mitigate brain damage induced by hypoxic-ischemic (HI) injury in rats and oxygen-glucose deprivation (OGD) in cortical primary neurons while exploring the underlying protective mechanisms. In vitro findings revealed that GSH-Au22 NCs enhanced cell activity, mitigated inflammatory reactions, and reduced oxidative stress induced by oxygen-glucose deprivation in cortical primary neurons. In vivo, GSH-Au22 NCs significantly diminished cerebral infarction volume, alleviated inflammatory responses, reduced oxidative stress, facilitated tissue structure recovery, attenuated apoptosis resulting from HIE, and enhanced long-term learning and memory abilities following HI injury. Mechanistically, GSH-Au22 NCs ameliorated the Sirt3/SOD2 signaling pathway, thereby exerting a protective effect against HIBD. Furthermore, the protective impact of GSH-Au22 NCs was reversed upon knocking down SOD2. In conclusion, our findings demonstrate that GSH-Au22 NCs modulate the Sirt3/SOD2 signaling pathway, thereby mitigating HI brain damage.

Mitochondria targeted nanoparticles for the treatment of mitochondrial dysfunction-associated brain disorders

Mitochondria play a significant role in several cellular activities and their function in health and disease has become an important area of research. Since the brain is a high-energy-demanding organ, it is particularly vulnerable to mitochondrial dysfunction. This has been implicated in several brain disorders including neurodegenerative, psychiatric and neurological disorders, e.g., Parkinson's disease and schizophrenia. Significant efforts are underway to develop mitochondria-targeting pharmaceutical interventions. However, the complex mitochondrial membrane network restricts the entry of therapeutic compounds into the mitochondrial matrix. Nanoparticles (NPs) present a novel solution to this limitation, while also increasing the stability of the therapeutic moieties and improving their bioavailability. This article provides a detailed overview of studies that have investigated the treatment of mitochondrial dysfunction in brain disorders using either targeted or non-targeted NPs as drug delivery systems. All the NPs showed improved mitochondrial functioning including a reduction in reactive oxygen species (ROS) production, an improvement in overall mitochondrial respiration and a reversal of toxin-induced mitochondrial damage. However, the mitochondrial-targeted NPs showed an advantage over the non-targeted NPs as they were able to improve or rescue mitochondrial dynamics and biogenesis, and they required a lower concentration of the in vivo therapeutic dosage of the drug load to show an effect. Consequently, mitochondria-targeted NPs are a promising therapeutic approach. Future studies should exploit advances in nanotechnology, neuroscience and chemistry to design NPs that can cross the blood-brain barrier and selectively target dysfunctional mitochondria, to improve treatment outcomes.

Nanoscale drug formulations for the treatment of Alzheimer's disease progression

Alzheimer's disease (AD) is a devastating neurodegenerative disorder with no effective disease-modifying treatments. The blood-brain barrier hinders drug delivery to the brain, limiting therapeutic efficacy. Nanoparticle-based systems have emerged as promising tools to overcome these challenges. This review highlights recent advances in nanoparticle technologies for AD treatment, including liposomes, polymeric, inorganic, and biomimetic nanoparticles. These nanoparticles improve drug delivery across the blood-brain barrier, improve stability and bioavailability, and enable targeted delivery to affected brain regions. Functionalization strategies further enhance their therapeutic potential. Multifunctional nanoparticles combining therapeutic and diagnostic properties offer theranostic approaches. While progress has been made, challenges related to safety, targeting precision, and clinical translation remain. Future perspectives emphasize the need for collaborative efforts to optimize nanoparticle design, conduct rigorous studies, and accelerate the development of effective nanotherapeutics. With continued innovation, nanoparticle-based delivery systems hold great promise for revolutionizing AD treatment.

Dietary Natural Melanin Nanozymes Delay Aging and Ameliorate Neurodegeneration via Improving Gut Microbiota and Redox Homeostasis

Aging is an inevitable multifactor process that causes a decline in organ function and increases the risk of age-related diseases and death. Thus, the development of highly effective and safe therapeutic strategies to delay aging and age-related diseases is urgently required. In this study, we isolated natural melanin nanozymes (NMNs) from the ink sacs of live octopuses. The NMNs exhibited excellent superoxide-dismutase-mimicking and radical scavenging activities. In SAMP8 mice, treatment with NMNs improved their cognition and memory functions while restoring their aging-impaired liver function and lipid metabolism, thereby prolonging their lifespan. Moreover, the NMNs reversed metabolic changes in their aged brains and reconstructed their gut microbiota composition by enhancing microbial community diversity. Our findings indicate that NMNs treatment could be a promising approach for delaying aging and preventing age-associated physiological decline in humans.

A multifunctional photothermal electrospun PLGA/MoS2@Pd nanofiber membrane for diabetic wound healing

Injury caused by excess reactive oxygen species (ROS) may lead to susceptibility to bacterial infection and sustained inflammatory response, which are the major factors impeding diabetic wound healing. By utilizing optimal anti-inflammatory, antioxidant and antibacterial biomaterials for multifunctional wound dressings is critical in clinical applications. In this study, a novel electrospun PLGA/MoS2@Pd nanofiber membrane was synthesized by encapsulating antioxidant and near-infrared (NIR) responsive MOS2@Pd nanozymes in PLGA nanofibers to form a multifunctional dressing for diabetic wound repair. With excellent biocompatibility and hemostatic ability, this novel PLGA/MoS2@Pd nanofiber membrane can effectively reduce oxidative stress damage and intracellular inflammatory factors expression in fibroblasts by scavenging ROS. Additionally, the PLGA/MoS2@Pd nanofiber membrane exhibited favorable NIR-mediated photothermal antibacterial activity in vitro, with inhibition rates of 97.14% and 97.07% against Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli), respectively. In a diabetic rat wound infection model, NIR-assisted PLGA/MoS2@Pd nanofiber membrane effectively inhibited bacterial growth in the wound, reduced infection-induced inflammatory response, and promoted tissue epithelialization and collagen deposition, resulting in a wound healing rate of up to 98.5% on Day 14. This study highlighted the construction of a multifunctional nanofiber membrane platform and demonstrated its promising potential as a clinical dressing for diabetic wounds.

Cerium oxide-modified Pd nanosheets encapsulated by red blood cell membranes for high-efficiency RONS scavenging in depression treatment

Depression, a common and high-morbidity mental illness, can cause severe physical and psychiatric disorder. Recently, elevated levels of reactive oxygen and nitrogen species (RONS) have been recognized as a potential pathogenesis of depression. Unfortunately, available therapies provide limited outcomes in treating RONS-related depression symptoms. In addition, the low blood-brain barrier (BBB) penetration efficiency of some drugs is another major barrier to depression treatment. This study developed cerium oxide-modified Pd (Pd-CeO2) nanosheets with outstanding antioxidant activities for depression therapy. Under physiological conditions, Pd-CeO2 exhibited significant O2˙- and H2O2 clearance through their superoxide dismutase (SOD) and catalase (CAT) activities. Meanwhile, Pd-CeO2 also displayed the ability to scavenge ˙OH and reactive nitrogen radicals (RNS). What's more, when incorporated with biocompatible red blood cell (RBC) membranes, Pd-CeO2@RBC could overcome the BBB and protect brain tissues from oxidative damage caused by RONS. As a result, Pd-CeO2@RBC therapy reduced the proliferation of microglia and astrocytes and alleviated neuroinflammation and depression-like behaviors. This research not only provides a novel strategy for the effective treatment of depression, but also paves the way for new therapeutic options of nanozymes in neurological disorders.

Recent advances in nanoenzymes for Alzheimer's disease treatment

Alzheimer's disease (AD) remains one of the most challenging neurodegenerative disorders to treat, with oxidative stress playing a significant role in its pathology. Recent advancements in nanoenzymes technology offer a promising approach to mitigate this oxidative damage. Nanoenzymes, with their unique enzyme-mimicking activities, effectively scavenge reactive oxygen species and reduce oxidative stress, thereby providing neuroprotective effects. This review delves into the underlying mechanisms of AD, focusing on oxidative stress and its impact on disease progression. We explore the latest developments in nanoenzymes applications for AD treatment, highlighting their multifunctional capabilities and potential for targeted delivery to amyloid-beta plaques. Despite the exciting prospects, the clinical translation of nanoenzymes faces several challenges, including difficulties in brain targeting, consistent quality production, and ensuring safety and biocompatibility. We discuss these limitations in detail, emphasizing the need for rigorous evaluation and standardized protocols. This paper aims to provide a comprehensive overview of the current state of nanoenzymes research in AD, shedding light on both the opportunities and obstacles in the path towards effective clinical applications.

Nanozymes targeting mitochondrial repair in disease treatment

Mitochondria are crucial sites for biological oxidation and substance metabolism and plays a vital role in maintaining intracellular homeostasis. When mitochondria undergo oxidative damage or dysfunction, they can harm the organism, leading to various reactive oxygen species (ROS)-related diseases. Therefore, therapies targeting mitochondria are a strategy for treating multiple diseases. Many nanozymes can mimic antioxidant enzymes, which enables them to eliminate ROS to mitigate mitochondrial dysfunction. The therapeutic approaches and drugs targeting the mitochondrial electron transport chain (ETC) have emerged as effective treatments for oxidative stress-related diseases resulting from mitochondrial respiratory chain disorders. Therefore, nanozymes that can regulate homeostasis in the mitochondrial ETC have emerged as effective therapeutic agents for treating oxidative stress-related diseases. In addition, benefit from the controllability and modifiability of nanozymes, their modification with TPP, SS-31 peptide, and mitochondrial permeability membrane peptide to eliminate ROS and repair mitochondrial function. The nanozymes that specifically target mitochondria are powerful tools for the treatment of ROS-associated disorders. We discussed the design strategies pertaining to mitochondrion-targeted nanozymes to treat various diseases to develop more efficacious nanozyme tools for the treatment of ROS-related diseases in the future.

Research Progress on the Strategies for Crossing the Blood-Brain Barrier

Recently, the incidence of brain diseases, such as central nervous system degenerative diseases, brain tumors, and cerebrovascular diseases, has increased. However, the blood-brain barrier (BBB) limits the effective delivery of drugs to brain disease areas. Therefore, the mainstream direction of new drug development for these diseases is to engineer drugs that can better cross the BBB to exert their effects in the brain. This paper reviews the research progress and application of the main trans-BBB drug delivery strategies (receptor/transporter-mediated BBB crossing, focused ultrasound to open the BBB, adenosine agonist reversible opening of the BBB, aromatic resuscitation, transnasal administration, cell-mediated trans-BBB crossing, and viral vector system-mediated brain drug delivery). Meanwhile, the potential applications, advantages, and disadvantages of these strategies for crossing the BBB are analyzed. Finally, the future development prospects of strategies for crossing the BBB are also discussed. These strategies have potential value for treating brain diseases.

Modified Ce/Zr-MOF Nanoparticles Loaded with Curcumin for Alzheimer's Disease via Multifunctional Modulation

Introduction

Alzheimer's disease (AD), a neurodegenerative condition, stands as the most prevalent form of dementia. Its complex pathological mechanisms and the formidable blood-brain barrier (BBB) pose significant challenges to current treatment approaches. Oxidative stress is recognized as a central factor in AD, underscoring the importance of antioxidative strategies in its treatment. In this study, we developed a novel brain-targeted nanoparticle, Ce/Zr-MOF@Cur-Lf, for AD therapy.

Methods

Layer-by-layer self-assembly technology was used to prepare Ce/Zr-MOF@Cur-Lf. In addition, the effect on the intracellular reactive oxygen species level, the uptake effect by PC12 and bEnd.3 cells and the in vitro BBB permeation effect were investigated. Finally, the mouse AD model was established by intrahippocampal injection of Aβ1-42, and the in vivo biodistribution, AD therapeutic effect and biosafety of the nanoparticles were researched at the animal level.

Results

As anticipated, Ce/Zr-MOF@Cur-Lf demonstrated efficient BBB penetration and uptake by PC12 cells, leading to attenuation of H2O2-induced oxidative damage. Moreover, intravenous administration of Ce/Zr-MOF@Cur-Lf resulted in rapid brain access and improvement of various pathological features of AD, including neuronal damage, amyloid-β deposition, dysregulated central cholinergic system, oxidative stress, and neuroinflammation.

Conclusion

Overall, Ce/Zr-MOF@Cur-Lf represents a promising approach for precise brain targeting and multi-target mechanisms in AD therapy, potentially serving as a viable option for future clinical treatment.

Nanozymes in Alzheimer's disease diagnostics and therapy

Alzheimer's disease (AD) is a progressive neurodegenerative condition that has become an important public health problem of global concern, and the early diagnosis and etiological treatment of AD are currently the focus of research. In the course of clinical treatment, approved clinical drugs mainly serve to slow down the disease process by relieving patients' clinical symptoms. However, these drugs do not target the cause of the disease, and the lack of specificity of these drugs has led to undesirable side effects in treatment. Meanwhile, AD is mainly diagnosed by clinical symptoms and imaging, which does not have the advantage of early diagnosis. Nanozymes have been extensively investigated for the diagnosis and treatment of AD with high stability and specificity. Therefore, this review summarizes the recent advances in various nanozymes for AD diagnosis and therapy, including with peroxidase-like-activity gold nanozymes, iron nanozymes, superoxide dismutase-like- and catalase-like-activity selenium dioxide nanozymes, platinum nanozymes, and peroxidase-like palladium nanozymes, among others. A comprehensive analysis was conducted on the diagnostic and therapeutic characteristics of nanozyme therapy for AD, as well as the prospects and challenges of its clinical application. Our goal is to advance this emerging topic by building on our own work and the new insights we have learned from others. This review will assist researchers to quickly understand relevant nanozymes' therapeutic and diagnostic information and further advance the field of nanozymes in AD.

Palladium nanocrystals regulates scleral extracellular matrix remodeling in myopic progression by modulating the hypoxia signaling pathway Nrf-2/Ho-1

Myopia represents a widespread global public health concern influenced by a combination of environmental and genetic factors. The prevailing theory explaining myopia development revolves around scleral extracellular matrix (ECM) remodeling, characterized by diminished Type I collagen (Col-1) synthesis and increased degradation, resulting in scleral thinning and eye axis elongation. Existing studies underscore the pivotal role of scleral hypoxia in myopic scleral remodeling. This study investigates the peroxidase-like activity and catalytic performance of octahedral Palladium (Pd) nanocrystals, recognized as nanozymes with antioxidative properties. We explore their potential in reducing oxidative stress and alleviating hypoxia in human scleral fibroblasts (HSF) and examine the associated molecular mechanisms. Our results demonstrate the significant peroxidase-like activity of Pd nanocrystals. Furthermore, we observe a substantial reduction in oxidative stress in HSF under hypoxia, mitigating cellular damage. These effects are linked to alterations in Nrf-2/Ho-1 expression, a pathway associated with hypoxic stress. Importantly, our findings indicate that Pd nanocrystals contribute to attenuated scleral matrix remodeling in myopic guinea pigs, effectively slowing myopia progression. This supports the hypothesis that Pd nanocrystals regulate myopia development by controlling oxidative stress associated with hypoxia. Based on these results, we propose that Pd nanocrystals represent a novel and potential treatment avenue for myopia through the modulation of scleral matrix remodeling. This study introduces innovative ideas and directions for the treatment and prevention of myopia.

Calcium Hexacyanoferrate (III) Nanocatalyst Enables Redox Homeostasis for Autism Spectrum Disorder Treatment

Autism spectrum disorder (ASD) is a multifaced neurodevelopmental disorder with considerable heterogeneity, in which over-generated reactive oxygen species (ROS) induce a cascade of pathological changes, including cellular apoptosis and inflammatory responses. Given the complex etiology of ASD, no effective treatment is available for ASD. In this work, a specific catalytic nanoenzyme, calcium hexacyanoferrate (III) nanocatalysts (CaH NCs), is designed and engineered for efficient ASD treatment. CaH NCs can mimic the activities of natural enzymes including superoxide dismutase, peroxidase, catalase, and glutathione peroxidase, which mitigates intracellular excessive ROS and regulates redox equilibrium. These CaH NCs modulate mitochondrial membrane potential, elevate B-cell lymphoma-2 levels, and suppress pro-apoptotic proteins, including Caspase-3 and B-cell lymphoma-2-associated X, thus effectively reducing cellular apoptosis. Importantly, CaH NCs alleviate inflammation by upregulating anti-inflammatory cytokine interleukin-10 and downregulating pro-inflammatory factors, resulting in attenuated activation of microglial and astrocytic and subsequent reduction in neuroinflammation. Subsequently, CaH NCs enhance social abilities, decrease anxiety levels, ameliorate repetitive behaviors, and improve learning and memory in ASD animal models through inflammation regulation and apoptosis inhibition. The CaH NCs in managing and preventing ASD represents a paradigm shift in autism treatment, paving the alternative but efficient way for clinical interventions in neurological conditions.

The potential use of nanozyme in aging and age-related diseases

The effects of an increasingly elderly population are among the most far-reaching in 21st-century society. The growing healthcare expense is mainly attributable to the increased incidence of chronic illnesses that accompany longer life expectancies. Different ideas have been put up to explain aging, but it is widely accepted that oxidative damage to proteins, lipids, and nucleic acids contributes to the aging process. Increases in life expectancy in all contemporary industrialized cultures are accompanied by sharp increases in the prevalence of age-related diseases such as cardiovascular and neurological conditions, type 2 diabetes, osteoporosis, and cancer. Therefore, academic and public health authorities should prioritize the development of therapies to increase health span. Nanozyme (NZ)-like activity in nanomaterials has been identified as promising anti-aging nanomedicines. More than that, nanomaterials displaying catalytic activities have evolved as artificial enzymes with high structural stability, variable catalytic activity, and functional diversity for use in a wide range of biological settings, including those dealing with age-related disorders. Due to their inherent enzyme-mimicking qualities, enzymes have attracted significant interest in treating diseases associated with reactive oxygen species (ROS). The effects of NZs on aging and age-related disorders are summarized in this article. Finally, prospects and threats to enzyme research and use in aging and age-related disorders are offered.

Reactive oxygen species-scavenging nanomaterials for the prevention and treatment of age-related diseases

With increasing proportion of the elderly in the population, age-related diseases (ARD) lead to a considerable healthcare burden to society. Prevention and treatment of ARD can decrease the negative impact of aging and the burden of disease. The aging rate is closely associated with the production of high levels of reactive oxygen species (ROS). ROS-mediated oxidative stress in aging triggers aging-related changes through lipid peroxidation, protein oxidation, and DNA oxidation. Antioxidants can control autoxidation by scavenging free radicals or inhibiting their formation, thereby reducing oxidative stress. Benefiting from significant advances in nanotechnology, a large number of nanomaterials with ROS-scavenging capabilities have been developed. ROS-scavenging nanomaterials can be divided into two categories: nanomaterials as carriers for delivering ROS-scavenging drugs, and nanomaterials themselves with ROS-scavenging activity. This study summarizes the current advances in ROS-scavenging nanomaterials for prevention and treatment of ARD, highlights the potential mechanisms of the nanomaterials used and discusses the challenges and prospects for their applications.

Neuromodulation by nanozymes and ultrasound during Alzheimer's disease management

Alzheimer's disease (AD) is a neurodegenerative disorder with complex pathogenesis and effective clinical treatment strategies for this disease remain elusive. Interestingly, nanomedicines are under extensive investigation for AD management. Currently, existing redox molecules show highly bioactive property but suffer from instability and high production costs, limiting clinical application for neurological diseases. Compared with natural enzymes, artificial enzymes show high stability, long-lasting catalytic activity, and versatile enzyme-like properties. Further, the selectivity and performance of artificial enzymes can be modulated for neuroinflammation treatments through external stimuli. In this review, we focus on the latest developments of metal, metal oxide, carbon-based and polymer based nanozymes and their catalytic mechanisms. Recent developments in nanozymes for diagnosing and treating AD are emphasized, especially focusing on their potential to regulate pathogenic factors and target sites. Various applications of nanozymes with different stimuli-responsive features were discussed, particularly focusing on nanozymes for treating oxidative stress-related neurological diseases. Noninvasiveness and focused application to deep body regions makes ultrasound (US) an attractive trigger mechanism for nanomedicine. Since a complete cure for AD remains distant, this review outlines the potential of US responsive nanozymes to develop future therapeutic approaches for this chronic neurodegenerative disease and its emergence in AD management.

Multifunctional Metal-Phenolic Composites Promote Efficient Periodontitis Treatment via Antibacterial and Osteogenic Properties

Periodontitis, a complex inflammatory disease initiated by bacterial infections, presents a significant challenge in public health. The increased levels of reactive oxygen species and the subsequent exaggerated immune response associated with periodontitis often lead to alveolar bone resorption and tooth loss. Herein, we develop multifunctional metal-phenolic composites (i.e., Au@MPN-BMP2) to address the complex nature of periodontitis, where gold nanoparticles (AuNPs) are coated by metal-phenolic networks (MPNs) and bone morphogenetic protein 2 (BMP2). In this design, MPNs exhibit remarkable antibacterial and antioxidant properties, and AuNPs and BMP2 promote osteogenic differentiation of bone marrow mesenchymal stem cells under inflammatory conditions. In a rat model of periodontitis, treatment with Au@MPN-BMP2 leads to notable therapeutic outcomes, including mitigated oxidative stress, reduced progression of inflammation, and the significant prevention of inflammatory bone loss. These results highlight the multifunctionality of Au@MPN-BMP2 nanoparticles as a promising therapeutic approach for periodontitis, addressing both microbial causative factors and an overactivated immune response. We envision that the rational design of metal-phenolic composites will provide versatile nanoplatforms for tissue regeneration and potential clinical applications.

Discovery of Effective Dual PROTAC Degraders for Neurodegenerative Disease-Associated Aggregates

The aggregation of specific proteins is a histopathological hallmark in various neurodegenerative diseases (NDs), among which Alpha-synuclein (α-Syn) and tau have received increased attention. The targeted protein degradation (TPD) strategy has been studied in the treatment of NDs, but multitarget bifunctional molecules have been ignored. Herein, a series of effective dual PROTAC degraders were developed, which could degrade α-Syn aggregates and total tau simultaneously. The degradation effects were evaluated in vitro, and the results showed that T3 could significantly knockdown α-Syn aggregates and total tau in the degradation efficiency with DC50 of 1.57 ± 0.55 and 4.09 ± 0.90 μM, respectively. Further mechanistic exploration showed that the degradation effect was mediated by the ubiquitin-proteasome system (UPS). Additionally, the therapeutic efficacy of T3 was confirmed in an MPTP-induced PD mouse model. Our results suggest that these dual PROTACs may provide a potential therapeutic strategy for NDs.

Borneol-modified docetaxel plus tetrandrine micelles for treatment of drug-resistant brain glioma

OBJECTIVE

Glioma is the most common and deadly primary malignant tumor in adults. Treatment outcomes are ungratified due to the presence of blood-brain barrier (BBB), glioma stem cells (GSCs) and multidrug resistance (MDR). Docetaxel (DTX) is considered as a potential drug for the treatment of brain tumor, but its effectiveness is limited by its low bioavailability and drug resistance. Tetrandrine (TET) reverses the resistance of tumor cells to chemotherapy drugs. Borneol (BO) modified in micelles has been shown to promote DTX plus TET to cross the BBB, allowing the drug to better act on tumors. Therefore, we constructed BO-modified DTX plus TET micelles to inhibit chemotherapeutic drug resistance.

SIGNIFICANCE

Provide a new treatment method for drug-resistant brain gliomas.

METHODS

In this study, BO-modified DTX plus TET micelles were prepared by thin film dispersion method, their physicochemical properties were characterized. Its targeting ability was investigated. The therapeutic effect on GSCs was investigated by in vivo and in vitro experiments.

RESULTS

The BO-modified DTX plus TET micelles were successfully constructed by thin film dispersion method, and the micelles showed good stability. The results showed that targeting micelles increased bEnd.3 uptake and helped drugs cross the BBB in vitro. And we also found that targeting micelles could inhibit cell proliferation, promote cell apoptosis and inhibit the expression of drug-resistant protein, thus provide a new treatment method for GSCs in vitro and in vivo.

CONCLUSIONS

BO-modified DTX plus TET micelles may provide a new treatment method for drug-resistant brain gliomas.

Vanadium Carbide Nanosheets with Broad-Spectrum Antioxidant Activity for Pulmonary Fibrosis Therapy

Idiopathic pulmonary fibrosis is a chronic and highly lethal lung disease that largely results from oxidative stress; however, effective antioxidant therapy by targeting oxidative stress pathogenesis is still lacking. The big challenge is to develop an ideal antioxidant material with superior antifibrotic effects. Herein, we report that V4C3 nanosheets (NSs) can serve as a potential antioxidant for treatment of pulmonary fibrosis by scavenging reactive oxygen and nitrogen species. Interestingly, subtle autoxidation can adjust the valence composition of V4C3 NSs and significantly improve their antioxidant behavior. Valence engineering triggers multiple antioxidant mechanisms including electron transfer, H atom transfer, and enzyme-like catalysis, thus endowing V4C3 NSs with broad-spectrum, high-efficiency, and persistent antioxidant capacity. Benefiting from antioxidant properties and good biocompatibility, V4C3 NSs can significantly prevent myofibroblast proliferation and extracellular matrix abnormality, thus alleviating the progression of bleomycin-induced pulmonary fibrosis in vivo by scavenging ROS, anti-inflammation, and rebuilding antioxidant defenses. This study not only provides an important strategy for designing excellent antioxidant nanomaterials, but also proposes a proof-of-concept demonstration for the treatment of pulmonary fibrosis and other oxidative stress-related diseases.

Versatile lipoprotein-inspired nanocomposites rescue Alzheimer's cognitive dysfunction by promoting Aβ degradation and lessening oxidative stress

The accumulation of amyloid-β (Aβ) into senile plaques and the resulting continuous oxidative stress are major pathogenic mechanisms in Alzheimer's disease (AD). In this study, we designed a lipoprotein-inspired nanoparticle to facilitate Aβ clearance and alleviate oxidative stress for the treatment of AD. Lipoprotein-like nanocomposites (RLA-rHDL@ANG) were fabricated by assembling reconstituted high density lipoprotein (rHDL) with an apoE-derived peptide (RLA) with Aβ binding and clearance capabilities, and were subsequently camouflaged using reactive oxygen species (ROS)-sensitive DSPE-TK-mPEG2000 and DSPE-TK-PEG3400-ANG with brain penetration as well as ROS scavenging ability. Immunoelectron microscopy, fluorescence colocalization, and enzyme linked immunosorbent assay, together with a thioflavin-T (ThT) fluorescence quantitative test, showed that RLA-rHDL@ANG possessed the ability of high binding affinity to both Aβ monomers and oligomers, and disintegration of pre-formed Aβ aggregates. ROS level monitoring and transmission electron microscopy (TEM) showed that RLA-rHDL@ANG possessed ROS sensitivity and consumption properties. Transcellular assay and in vivo imaging showed that RLA-rHDL@ANG effectively facilitated blood-brain barrier (BBB) penetration and intracerebral accumulation. It promoted the efficient degradation of Aβ by microglia and neurons through lysosomal transport and elimination approaches. Four-week administration of RLA-rHDL@ANG effectively reduced Aβ deposition, decreased the ROS level and improved cognitive functions in AD mice. These findings indicate that multifunctional RLA-rHDL@ANG may serve as a promising and feasible candidate for managing the progression of AD.

RuCu Nanosheets with Ultrahigh Nanozyme Activity for Chemodynamic Therapy

Nanoenzymes have been widely explored for chemodynamic therapy (CDT) in cancer treatment. However, poor catalytic efficiency of nanoenzymes, especially in the tumor microenvironment with insufficient H2 O2 and mild acidity, limits the effect of CDT. Herein, a new ultrathin RuCu nanosheet (NS) based nanoenzyme which has a large specific surface area and abundant channels and defects is developed. The RuCu NSs show superb catalytic efficiency for the oxidation of peroxidase substrate H2 O2 at a wide range of pH and their catalytic efficiency (kcat /Km = 177.2 m-1  s-1 ) is about 14.9 times higher than that of the single-atom catalyst FeN3 P. Besides being an efficient nanozyme as peroxidase, the RuCu NSs possess other two enzyme activities, not only disproportionating superoxide anion to produce H2 O2 but also consuming glutathione to keep a high concentration of H2 O2 in the tumor microenvironment for Fenton reaction. With these advantages, the RuCu NSs exhibit good performance to kill cancer cells and inhibit tumor growth in mice, demonstrating a promising potential as new CDT reagent.

Trimanganese Tetroxide Nanozyme protects Cartilage against Degeneration by Reducing Oxidative Stress in Osteoarthritis

Osteoarthritis, a chronic degenerative cartilage disease, is the leading cause of movement disorders among humans. Although the specific pathogenesis and associated mechanisms remain unclear, oxidative stress-induced metabolic imbalance in chondrocytes plays a crucial role in the occurrence and development of osteoarthritis. In this study, a trimanganese tetroxide (Mn3 O4 ) nanozyme with superoxide dismutase (SOD)-like and catalase (CAT)-like activities is designed to reduce oxidative stress-induced damage and its therapeutic effect is investigated. In vitro, Mn3 O4 nanozymes are confirmed to reprogram both the imbalance of metabolism in chondrocytes and the uncontrolled inflammatory response stimulated by hydrogen peroxide. In vivo, a cross-linked chondroitin sulfate (CS) hydrogel is designed as a substrate for Mn3 O4 nanozymes to treat osteoarthritis in mouse models. As a result, even in the early stage of OA (4 weeks), the therapeutic effect of the Mn3 O4 @CS hydrogel is observed in both cartilage metabolism and inflammation. Moreover, the Mn3 O4 @CS hydrogel maintained its therapeutic effects for at least 7 days, thus revealing a broad scope for future clinical applications. In conclusion, these results suggest that the Mn3 O4 @CS hydrogel is a potentially effective therapeutic treatment for osteoarthritis, and a novel therapeutic strategy for osteoarthritis based on nanozymes is proposed.

Polydopamine-Pd nanozymes as potent ROS scavengers in combination with near-infrared irradiation for osteoarthritis treatment

Excessive reactive oxygen species (ROS) in joints could lead to gradual degeneration of the extracellular matrix (ECM) and apoptosis of chondrocytes, contributing to the occurrence and development of osteoarthritis (OA). Mimicking natural enzymes, polydopamine (PDA)-based nanozymes showed great potential in treating various inflammatory diseases. In this work, PDA loaded with ultra-small palladium (PDA-Pd) nanoparticles (NPs) was employed to scavenge ROS for OA therapy. As a result, PDA-Pd effectively declined the intracellular ROS levels and exhibited efficient antioxidative and anti-inflammatory capacity with good biocompatibility in IL-1β stimulated chondrocytes. Significantly, assisted with near-infrared (NIR) irradiation, its therapeutic effect was further enhanced. Further, NIR-stimulated PDA-Pd suppressed the progression of OA after intra-articular injection in the OA rat model. With favorable biocompatibility, PDA-Pd exhibits efficient antioxidative and anti-inflammatory capacity, leading to the alleviation of OA in rats. Our findings may provide new insights into the treatment of various ROS-induced inflammatory diseases.

Structural Analysis and Intrinsic Enzyme Mimicking Activities of Ligand-Free PtAg Nanoalloys

Nanozymes are nanomaterials with biocatalytic properties under physiological conditions and are one class of artificial enzymes to overcome the high cost and low stability of natural enzymes. However, surface ligands on nanomaterials will decrease the catalytic activity of the nanozymes by blocking the active sites. To address this limitation, ligand-free PtAg nanoclusters (NCs) are synthesized and applied as nanozymes for various enzyme-mimicking reactions. By taking advantage of the mutual interaction of zeolitic imidazolate frameworks (ZIF-8) and Pt precursors, a good dispersion of PtAg bimetal NCs with a diameter of 1.78 ± 0.1 nm is achieved with ZIF-8 as a template. The incorporation of PtAgNCs in the voids of ZIF-8 is confirmed with structural analysis using the atomic pair-distribution function and powder X-ray diffraction. Importantly, the PtAgNCs present good catalytic activity for various enzyme-mimicking reactions, including peroxidase-/catalase- and oxidase-like reactions. Further, this work compares the catalytic activity between PtAg NCs and PtAg nanoparticles with different compositions and finds that these two nanozymes present a converse dependency of Ag-loading on their activity. This study contributes to the field of nanozymes and presents a potential option to prepare ligand-free bimetal biocatalysts with sizes in the nanocluster regime.

The role of crystallinity of palladium nanocrystals in ROS generation and cytotoxicity induction

Palladium (Pd) nanocrystals with different crystalline forms exhibit distinct enzyme-like activities in generating reactive oxygen species (ROS). How such crystallinity-dependent catalytic activity regulates potential cytotoxicity remains to be elucidated. In the present work, Pd nanocrystals with four different crystalline forms were synthesized, and the underlying mechanisms involved in ROS-mediated cytotoxicity were systematically revealed. Pd nanocrystals with the {100} (nanocubes) and {111} (nanooctahedrons and nanotetrahedrons) facets triggered cytotoxicity by generating singlet oxygen (¹O₂) and hydroxyl radicals (OH˙), respectively. Meanwhile, Pd nanoconcave-tetrahedrons, which had both the {110} and {111} facets, induced ROS-mediated cytotoxicity via activating the superoxide (O₂˙^-) pathway. Consumption of protons and generation of hydroxide during intracellular ROS conversion resulted in pH alkalization, eventually leading to cell death. Our findings emphasize the importance of facet-dependent ROS generation promoted by Pd nanocrystals. Furthermore, alkalization is identified as a new biomarker for analyzing ROS-mediated cytotoxicity.

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.

Nanozyme-Enabled Treatment of Cardio- and Cerebrovascular Diseases

Cardio- and cerebrovascular diseases are two major vascular-related diseases that lead to death worldwide. Reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of diseases. Excessive ROS induce cellular context damage and lead to tissue dysfunction. Nanozymes, as emerging enzyme mimics, offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of ROS-related cardio- and cerebrovascular diseases by directly scavenging excess ROS or regulating pathologically related molecules. This review first introduces nanozyme-enabled therapeutic mechanisms at the cellular level. Then, the therapies for several typical cardio- and cerebrovascular diseases with nanozymes are discussed, mainly including cardiovascular diseases, ischemia reperfusion injury, and neurological disorders. Finally, the challenges and outlooks for the application of nanozymes are also presented. This review will provide some instructive perspectives on nanozymes and promote the development of enzyme-mimicking strategies in cardio- and cerebrovascular disease therapy.

Natural Morin-Based Metal Organic Framework Nanoenzymes Modulate Articular Cavity Microenvironment to Alleviate Osteoarthritis

Osteoarthritis (OA) is always characterized as excessive reactive oxygen species (ROS) inside articular cavity. Mimicking natural metalloenzymes with metal ions as the active centers, stable metal organic framework (MOF) formed by natural polyphenols and metal ions shows great potential in alleviating inflammatory diseases. Herein, a series of novel copper-morin-based MOF (CuMHs) with different molar ratios of Cu²⁺ and MH were employed to serve as ROS scavengers for OA therapy. As a result, CuMHs exhibited enhanced dispersion in aqueous solution, improved biocompatibility, and efficient ROS-scavenging ability compared to MH. On the basis of H₂O₂-stimulated chondrocytes, intracellular ROS levels were efficiently declined and cell death was prevented after treated by Cu₆MH (Cu²⁺ and MH molar ratio of 6:1). Meanwhile, Cu₆MH also exhibited efficient antioxidant and anti-inflammation function by down-regulating the expression of IL6, MMP13, and MMP3, and up-regulating cartilage specific gene expression as well. Importantly, Cu₆MH could repair mitochondrial function by increasing mitochondrial membrane potential, reducing the accumulation of calcium ions, as well as promoting ATP content production. In OA joint model, intra-articular (IA) injected Cu₆MH suppressed the progression of OA. It endowed that Cu₆MH might be promising nanoenzymes for the prevention and treatment of various inflammatory diseases.

Nanozymes for Regenerative Medicine

Nanozymes refer to nanomaterials that catalyze enzyme substrates into products under relevant physiological conditions following enzyme kinetics. Compared to natural enzymes, nanozymes possess the characteristics of higher stability, easier preparation, and lower cost. Importantly, nanozymes possess the magnetic, fluorescent, and electrical properties of nanomaterials, making them promising replacements for natural enzymes in industrial, biological, and medical fields. On account of the rapid development of nanozymes recently, their application potentials in regeneration medicine are gradually being explored. To highlight the achievements in the regeneration medicine field, this review summarizes the catalytic mechanism of four types of representative nanozymes. Then, the strategies to improve the biocompatibility of nanozymes are discussed. Importantly, this review covers the recent advances in nanozymes in tissue regeneration medicine including wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment. In addition, challenges and prospects of nanozyme researches in regeneration medicine are summarized.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.