Neutrophil-like Cell-Membrane-Coated Nanozyme Therapy for Ischemic Brain Damage and Long-Term Neurological Functional Recovery

Microenvironment-sensitive nanozymes for tissue regeneration

Tissue defect is one of the significant challenges encountered in clinical practice. Nanomaterials, including nanoparticles, nanofibers, and metal-organic frameworks, have demonstrated an extensive potential in tissue regeneration, offering a promising avenue for future clinical applications. Nonetheless, the intricate landscape of the inflammatory tissue microenvironment has engendered challenges to the efficacy of nanomaterial-based therapies. This quandary has spurred researchers to pivot towards advanced nanotechnological remedies for overcoming these therapeutic constraints. Among these solutions, microenvironment-sensitive nanozymes have emerged as a compelling instrument with the capacity to reshape the tissue microenvironment and enhance the intricate process of tissue regeneration. In this review, we summarize the microenvironmental characteristics of damaged tissues, offer insights into the rationale guiding the design and engineering of microenvironment-sensitive nanozymes, and explore the underlying mechanisms that underpin these nanozymes' responsiveness. This analysis includes their roles in orchestrating cellular signaling, modulating immune responses, and promoting the delicate process of tissue remodeling. Furthermore, we discuss the diverse applications of microenvironment-sensitive nanozymes in tissue regeneration, including bone, soft tissue, and cartilage regeneration. Finally, we shed our sights on envisioning the forthcoming milestones in this field, prospecting a future where microenvironment-sensitive nanozymes contribute significantly to the development of tissue regeneration and improved clinical outcomes.

Stimuli-responsive polymer-based nanosystems for cardiovascular disease theranostics

Stimulus-responsive polymers have found widespread use in biomedicine due to their ability to alter their own structure in response to various stimuli, including internal factors such as pH, reactive oxygen species (ROS), and enzymes, as well as external factors like light. In the context of atherosclerotic cardiovascular diseases (CVDs), stimulus-response polymers have been extensively employed for the preparation of smart nanocarriers that can deliver therapeutic and diagnostic drugs specifically to inflammatory lesions. Compared with traditional drug delivery systems, stimulus-responsive nanosystems offer higher sensitivity, greater versatility, wider applicability, and enhanced biosafety. Recent research has made significant contributions towards designing stimulus-responsive polymer nanosystems for CVDs diagnosis and treatment. This review summarizes recent advances in this field by classifying stimulus-responsive polymer nanocarriers according to different responsiveness types and describing numerous stimuli relevant to these materials. Additionally, we discuss various applications of stimulus-responsive polymer nanomaterials in CVDs theranostics. We hope that this review will provide valuable insights into optimizing the design of stimulus-response polymers for accelerating their clinical application in diagnosing and treating CVDs.

Nanozymes: Potential Therapies for Reactive Oxygen Species Overproduction and Inflammation in Ischemic Stroke and Traumatic Brain Injury

Nanozymes, which can selectively scavenge reactive oxygen species (ROS), have recently emerged as promising candidates for treating ischemic stroke and traumatic brain injury (TBI) in preclinical models. ROS overproduction during the early phase of these diseases leads to oxidative brain damage, which has been a major cause of mortality worldwide. However, the clinical application of ROS-scavenging enzymes is limited by their short in vivo half-life and inability to cross the blood-brain barrier. Nanozymes, which mimic the catalytic function of natural enzymes, have several advantages, including cost-effectiveness, high stability, and easy storage. These advantages render them superior to natural enzymes for disease diagnosis and therapeutic interventions. This review highlights recent advancements in nanozyme applications for ischemic stroke and TBI, emphasizing their potential to mitigate the detrimental effect of ROS overproduction, oxidative brain damage, inflammation, and blood-brain barrier compromise. Therefore, nanozymes represent a promising treatment modality for ROS overproduction conditions in future medical practices.

Reduction of Oxidative Stress and Excitotoxicity by Mesenchymal Stem Cell Biomimetic Co-Delivery System for Cerebral Ischemia-Reperfusion Injury Treatment

A cerebral ischemia-reperfusion injury is ensued by an intricate interplay between various pathological processes including excitotoxicity, oxidative stress, inflammation, and apoptosis. For a long time, drug intervention policies targeting a single signaling pathway have failed to achieve the anticipated clinical efficacy in the intricate and dynamic inflammatory environment of the brain. Moreover, inadequate targeted drug delivery remains a significant challenge in cerebral ischemia-reperfusion injury therapy. In this study, a multifunctional nanoplatform (designated as PB-006@MSC) is developed using ZL006-loaded Prussian blue nanoparticles (PBNPs) camouflaged by a mesenchymal stem cell (MSC) membrane (MSCm). ZL006 is a neuroprotectant. It can be loaded efficiently into the free radical scavenger PBNP through mesoporous adsorption. This can simultaneously modulate multiple targets and pathways. MSCm biomimetics can reduce the nanoparticle immunogenicity, efficiently enhance their homing capability to the cerebral ischemic penumbra, and realize active-targeting therapy for ischemic stroke. In animal experiments, PB-006@MSC integrated reactive oxygen species (ROS) scavenging and neuroprotection. Thereby, it selectively targeted the cerebral ischemic penumbra (about fourfold higher accumulation at 24 h than in the non-targeted group), demonstrated a remarkable therapeutic efficacy in reducing the volume of cerebral infarction (from 37.1% to 2.3%), protected the neurogenic functions, and ameliorated the mortality.

Developing targeted antioxidant nanomedicines for ischemic penumbra: Novel strategies in treating brain ischemia-reperfusion injury

During cerebral ischemia-reperfusion conditions, the excessive reactive oxygen species in the ischemic penumbra region, resulting in neuronal oxidative stress, constitute the main pathological mechanism behind ischemia-reperfusion damage. Swiftly reinstating blood perfusion in the ischemic penumbra zone and suppressing neuronal oxidative injury are key to effective treatment. Presently, antioxidants in clinical use suffer from low bioavailability, a singular mechanism of action, and substantial side effects, severely restricting their therapeutic impact and widespread clinical usage. Recently, nanomedicines, owing to their controllable size and shape and surface modifiability, have demonstrated good application potential in biomedicine, potentially breaking through the bottleneck in developing neuroprotective drugs for ischemic strokes. This manuscript intends to clarify the mechanisms of cerebral ischemia-reperfusion injury and provides a comprehensive review of the design and synthesis of antioxidant nanomedicines, their action mechanisms and applications in reversing neuronal oxidative damage, thus presenting novel approaches for ischemic stroke prevention and treatment.

Enhanced diabetic wound healing with injectable hydrogel containing self-assembling nanozymes

To build a smart system in response to the variable microenvironment in infected diabetic wounds, a multifunctional wound dressing was constructed by co-incorporating glucose oxidase (GOx) and a pH-responsive self-assembly Cu2-xSe-BSA nanozyme into a dual-dynamic bond cross-linked hydrogel (OBG). This composite hydrogel (OBG@CG) can adhere to the wound site and respond to the acidic inflammatory environment, initiating the GOx-catalyzed generation of H2O2 and the self-assembly activated peroxidase-like property of Cu2-xSe-BSA nanozymes, resulting in significant hydroxyl radical production to attack the biofilm during the acute infection period and alleviate the high-glucose microenvironment for better wound healing. During the wound recovery phase, Cu2-xSe-BSA aggregates disassembled owing to the elevated pH, terminating catalytic reactive oxygen species generation. Simultaneously, Cu2+ released from the Cu2-xSe-BSA not only promotes the production of mature collagen but also enhances the migration and proliferation of endothelial cells. RNA-seq analysis demonstrated that OBG@CG exerted its antibacterial property by damaging the integrity of the biofilm by inducing radicals and interfering with the energy supply, along with destroying the defense system by disturbing thiol metabolism and reducing transporter activities. This work proposes an innovative glucose consumption strategy for infected diabetic wound management, which may inspire new ideas in the exploration of smart wound dressing.

Targeted Delivery of Macrophage Membrane Biomimetic Liposomes Through Intranasal Administration for Treatment of Ischemic Stroke

Purpose

Ginsenoside Rg3 (Rg3) and Panax notoginseng saponins (PNS) can be used for ischemic stroke treatment, however, the lack of targeting to the ischemic region limits the therapeutic effect. To address this, we leveraged the affinity of macrophage membrane proteins for inflamed brain microvascular endothelial cells to develop a macrophage membrane-cloaked liposome loaded with Rg3 and PNS (MM-Lip-Rg3/PNS), which can precisely target brain lesion region through intranasal administration.

Methods

MM-Lip-Rg3/PNS was prepared by co-extrusion method and was performed by characterization, stability, surface protein, and morphology. The cellular uptake, immune escape ability, and blood-brain barrier crossing ability of MM-Lip-Rg3/PNS were studied in vitro. The in vivo brain targeting, biodistribution and anti-ischemic efficacy of MM-Lip-Rg3/PNS were evaluated in MACO rats, and we determined the diversity of the nasal brain pathway through the olfactory nerve blockade model in rats. Finally, the pharmacokinetics and brain targeting index of MM-Lip-Rg3/PNS were investigated.

Results

Our results indicated that MM-Lip-Rg3/PNS was spherical with a shell-core structure. MM-Lip-Rg3/PNS can avoid mononuclear phagocytosis, actively bind to inflammatory endothelial cells, and have the ability to cross the blood-brain barrier. Moreover, MM-Lip-Rg3/PNS could specifically target ischemic sites, even microglia, increase the cumulative number of drugs in the brain, improve the inflammatory environment of the brain, and reduce the infarct size. By comparing olfactory nerve-blocking rats with normal rats, it was found that there are direct and indirect pathways for nasal entry into the brain. Pharmacokinetics demonstrated that MM-Lip-Rg3/PNS exhibited stronger brain targeting and prolonged drug half-life.

Conclusion

MM-Lip-Rg3/PNS might contribute to the accumulation of Rg3 and PNS in the ischemic brain area to improve treatment efficacy. This biomimetic nano-drug delivery system provides a new and promising strategy for the treatment of ischemic stroke.

Revolutionizing Neurocare: Biomimetic Nanodelivery Via Cell Membranes

Brain disorders represent a significant challenge in medical science due to the formidable blood-brain barrier (BBB), which severely limits the penetration of conventional therapeutics, hindering effective treatment strategies. This review delves into the innovative realm of biomimetic nanodelivery systems, including stem cell-derived nanoghosts, tumor cell membrane-coated nanoparticles, and erythrocyte membrane-based carriers, highlighting their potential to circumvent the BBB's restrictions. By mimicking native cell properties, these nanocarriers emerge as a promising solution for enhancing drug delivery to the brain, offering a strategic advantage in overcoming the barrier's selective permeability. The unique benefits of leveraging cell membranes from various sources is evaluated and advanced technologies for fabricating cell membrane-encapsulated nanoparticles capable of masquerading as endogenous cells are examined. This enables the targeted delivery of a broad spectrum of therapeutic agents, ranging from small molecule drugs to proteins, thereby providing an innovative approach to neurocare. Further, the review contrasts the capabilities and limitations of these biomimetic nanocarriers with traditional delivery methods, underlining their potential to enable targeted, sustained, and minimally invasive treatment modalities. This review is concluded with a perspective on the clinical translation of these biomimetic systems, underscoring their transformative impact on the therapeutic landscape for intractable brain diseases.

Subacute ruminal acidosis induces pyroptosis via the mitophagy-mediated NLRP3 inflammasome activation in the livers of dairy cows fed a high-grain diet

High-grain (HG) feeding can trigger subacute ruminal acidosis (SARA) and subsequent liver tissue injury. This study investigated pyroptosis and NLRP3 inflammasome activation in SARA-induced liver injury, and the role of mitophagy during this process. Twelve mid-lactating Holstein cows equipped with rumen fistulas were randomly divided into 2 groups: a low-grain (LG) diet group (grain:forage = 4:6) and a HG diet group (grain:forage = 6:4). Each group had 6 cows. The experiment lasted for 3 wk. The ruminal fluid was collected through the rumen fistula on experimental d 20 and 21, and the pH immediately measured. At the end of the experiment, all animals were slaughtered, and peripheral blood and liver tissue were collected. The ruminal pH was lower in the HG group than that in the LG group at all time points. In addition, the ruminal pH in the HG group was lower than 5.6 at 3 consecutive time points after feeding (4, 6, and 8 h on d 20; 2, 4, and 6 h on d 21), indicating that HG feeding induced SARA. The content of lipopolysaccharide, IL-1β, and apoptosis-related cysteine protease 1 (caspase-1) and the activity of alanine aminotransferase and aspartate aminotransferase in the blood plasma of the HG group were all significantly increased. Hepatic caspase-1 activity was increased in the livers of the HG group. The increased expression levels of pyroptosis- and NLRP3 inflammasome-related genes IL1B, IL18, gasdermin D (GSDMD), apoptosis-associated speck-like protein containing a card (ASC), NLR family pyrin domain-containing 3 (NLRP3), and caspase-1 (CASP1) in liver tissue of the HG group were detected. Furthermore, western blot analysis showed that HG feeding led to increased expression of pyroptosis- and NLRP3 inflammasome-related proteins GSDMD N-terminal (GSDMD-NT), IL-1β, IL-18, cleaved-caspase-1, ASC, NLRP3, and cleaved-caspase-11 and upregulated expression of mitophagy-related proteins microtubule-associated protein 1 light chain 3 II (MAP1LC3-II), beclin 1 (BECN1), Parkin, and PTEN-induced kinase 1 (PINK1) in liver tissue. Collectively, our results revealed that SARA caused increased mitophagy and activated the NLRP3 inflammasome, causing pyroptosis and subsequent liver injury in dairy cows fed a HG diet.

Cell-membrane engineering strategies for clinic-guided design of nanomedicine

Cells are the fundamental units of life. The cell membrane primarily composed of two layers of phospholipids (a bilayer) structurally defines the boundary of a cell, which can protect its interior from external disturbances and also selectively exchange substances and conduct signals from the extracellular environment. The complexity and particularity of transmembrane proteins provide the foundation for versatile cellular functions. Nanomedicine as an emerging therapeutic strategy holds tremendous potential in the healthcare field. However, it is susceptible to recognition and clearance by the immune system. To overcome this bottleneck, the technology of cell membrane coating has been extensively used in nanomedicines for their enhanced therapeutic efficacy, attributed to the favorable fluidity and biocompatibility of cell membranes with various membrane-anchored proteins. Meanwhile, some engineering strategies of cell membranes through various chemical, physical and biological ways have been progressively developed to enable their versatile therapeutic functions against complex diseases. In this review, we summarized the potential clinical applications of four typical cell membranes, elucidated their underlying therapeutic mechanisms, and outlined their current engineering approaches. In addition, we further discussed the limitation of this technology of cell membrane coating in clinical applications, and possible solutions to address these challenges.

Application and advances of biomimetic membrane materials in central nervous system disorders

Central nervous system (CNS) diseases encompass spinal cord injuries, brain tumors, neurodegenerative diseases, and ischemic strokes. Recently, there has been a growing global recognition of CNS disorders as a leading cause of disability and death in humans and the second most common cause of death worldwide. The global burdens and treatment challenges posed by CNS disorders are particularly significant in the context of a rapidly expanding global population and aging demographics. The blood-brain barrier (BBB) presents a challenge for effective drug delivery in CNS disorders, as conventional drugs often have limited penetration into the brain. Advances in biomimetic membrane nanomaterials technology have shown promise in enhancing drug delivery for various CNS disorders, leveraging properties such as natural biological surfaces, high biocompatibility and biosafety. This review discusses recent developments in biomimetic membrane materials, summarizes the types and preparation methods of these materials, analyzes their applications in treating CNS injuries, and provides insights into the future prospects and limitations of biomimetic membrane materials.

Single-Atom-Based Nanoenzyme in Tissue Repair

Since the discovery of ferromagnetic nanoparticles Fe3O4 that exhibit enzyme-like activity in 2007, the research on nanoenzymes has made significant progress. With the in-depth study of various nanoenzymes and the rapid development of related nanotechnology, nanoenzymes have emerged as a promising alternative to natural enzymes. Within nanozymes, there is a category of metal-based single-atom nanozymes that has been rapidly developed due to low cast, convenient preparation, long storage, less immunogenicity, and especially higher efficiency. More importantly, single-atom nanozymes possess the capacity to scavenge reactive oxygen species through various mechanisms, which is beneficial in the tissue repair process. Herein, this paper systemically highlights the types of metal single-atom nanozymes, their catalytic mechanisms, and their recent applications in tissue repair. The existing challenges are identified and the prospects of future research on nanozymes composed of metallic nanomaterials are proposed. We hope this review will illuminate the potential of single-atom nanozymes in tissue repair, encouraging their sequential clinical translation.

Advancing stroke therapy: the potential of MOF-based nanozymes in biomedical applications

In this study, we explored the growing use of metal-organic framework (MOF)-based Nanozymes in biomedical research, with a specific emphasis on their applications in stroke therapy. We have discussed the complex nature of stroke pathophysiology, highlighting the crucial role of reactive oxygen species (ROS), and acknowledging the limitations of natural enzymes in addressing these challenges. We have also discussed the role of nanozymes, particularly those based on MOFs, their structural similarities to natural enzymes, and their potential to improve reactivity in various biomedical applications. The categorization of MOF nanozymes based on enzyme-mimicking activities is discussed, and their applications in stroke therapy are explored. We have reported the potential of MOF in treating stroke by regulating ROS levels, alleviation inflammation, and reducing neuron apoptosis. Additionally, we have addressed the challenges in developing efficient antioxidant nanozyme systems for stroke treatment. The review concludes with the promise of addressing these challenges and highlights the promising future of MOF nanozymes in diverse medical applications, particularly in the field of stroke treatment.

Nanozyme as a rising star for metabolic disease management

Nanozyme, characterized by outstanding and inherent enzyme-mimicking properties, have emerged as highly promising alternatives to natural enzymes owning to their exceptional attributes such as regulation of oxidative stress, convenient storage, adjustable catalytic activities, remarkable stability, and effortless scalability for large-scale production. Given the potent regulatory function of nanozymes on oxidative stress and coupled with the fact that reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of metabolic diseases, nanozyme offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of metabolic diseases by directly scavenging excess ROS or regulating pathologically related molecules. The rational design strategies, nanozyme-enabled therapeutic mechanisms at the cellular level, and the therapies of nanozyme for several typical metabolic diseases and underlying mechanisms are discussed, mainly including obesity, diabetes, cardiovascular disease, diabetic wound healing, and others. Finally, the pharmacokinetics, safety analysis, challenges, and outlooks for the application of nanozyme are also presented. This review will provide some instructive perspectives on nanozyme and promote the development of enzyme-mimicking strategies in metabolic disease therapy.

Convergence of nanomedicine and neutrophils for drug delivery

Neutrophils have recently emerged as promising carriers for drug delivery due to their unique properties including rapid response toward inflammation, chemotaxis, and transmigration. When integrated with nanotechnology that has enormous advantages in improving treatment efficacy and reducing side effects, neutrophil-based nano-drug delivery systems have expanded the repertoire of nanoparticles employed in precise therapeutic interventions by either coating nanoparticles with their membranes, loading nanoparticles inside living cells, or engineering chimeric antigen receptor (CAR)-neutrophils. These neutrophil-inspired therapies have shown superior biocompatibility, targeting ability, and therapeutic robustness. In this review, we summarized the benefits of combining neutrophils and nanotechnologies, the design principles and underlying mechanisms, and various applications in disease treatments. The challenges and prospects for neutrophil-based drug delivery systems were also discussed.

Engineering and Targeting Neutrophils for Cancer Therapy

Neutrophils are the most abundant white blood cells in the circulation and act as the first line of defense against infections. Increasing evidence suggests that neutrophils possess heterogeneous phenotypes and functional plasticity in human health and diseases, including cancer. Neutrophils play multifaceted roles in cancer development and progression, and an N1/N2 paradigm of neutrophils in cancer is proposed, where N1 neutrophils exert anti-tumor properties while N2 neutrophils display tumor-supportive and immune-suppressive functions. Selective activation of beneficial neutrophil population and targeted inhibition or re-polarization of tumor-promoting neutrophils has shown an important potential in tumor therapy. In addition, due to the natural inflammation-responsive and physical barrier-crossing abilities, neutrophils and their derivatives (membranes and extracellular vesicles (EVs)) are regarded as advanced drug delivery carriers for enhanced tumor targeting and improved therapeutic efficacy. In this review, the recent advances in engineering neutrophils for drug delivery and targeting neutrophils for remodeling tumor microenvironment (TME) are comprehensively presented. This review will provide a broad understanding of the potential of neutrophils in cancer therapy.

A Neutrophil Hijacking Nanoplatform Reprograming NETosis for Targeted Microglia Polarizing Mediated Ischemic Stroke Treatment

Precise and efficient regulation of microglia is vital for ischemic stroke therapy and prognosis. The infiltration of neutrophils into the brain provides opportunities for regulatory drugs across the blood-brain barrier, while hindered by neutrophil extracellular traps (NETs) and targeted delivery of intracerebral drugs to microglia. This study reports an efficient neutrophil hijacking nanoplatform (referred to as APTS) for targeted A151 (a telomerase repeat sequence) delivery to microglia without the generation of NETs. In the middle cerebral artery occlusion (MCAO) mouse model, the delivery efficiency to ischemic stroke tissues increases by fourfold. APTS dramatically reduces the formation of NETs by 2.2-fold via reprogramming NETosis to apoptosis in neutrophils via a reactive oxygen species scavenging-mediated citrullinated histone 3 inhibition pathway. Noteworthy, A151 within neutrophils is repackaged into apoptotic bodies following the death pattern reprogramming, which, when engulfed by microglia, polarizes microglia to an anti-inflammatory M2 phenotype. After four times treatment, the cerebral infarction area in the APTS group decreases by 5.1-fold. Thus, APTS provides a feasible, efficient, and practical drug delivery approach for reshaping the immune microenvironment and treating brain disorders in the central nervous system.

Platinum-Loaded Cerium Oxide Capable of Repairing Neuronal Homeostasis for Cerebral Ischemia-Reperfusion Injury Therapy

Effective neuroprotective agents are required to prevent neurological damage caused by reactive oxygen species (ROS) generated by cerebral ischemia-reperfusion injury (CIRI) following an acute ischemic stroke. Herein, it is aimed to develop the neuroprotective agents of cerium oxide loaded with platinum clusters engineered modifications (Ptn-CeO2). The density functional theory calculations show that Ptn-CeO2 could effectively scavenge ROS, including hydroxyl radicals (·OH) and superoxide anions (·O2 -). In addition, Ptn-CeO2 exhibits the superoxide dismutase- and catalase-like enzyme activities, which is capable of scavenging hydrogen peroxide (H2O2). The in vitro studies show that Ptn-CeO2 could adjust the restoration of the mitochondrial metabolism to ROS homeostasis, rebalance cytokines, and feature high biocompatibility. The studies in mice CIRI demonstrate that Ptn-CeO2 could also restore cytokine levels, reduce cysteine aspartate-specific protease (cleaved Caspase 3) levels, and induce the polarization of microglia to M2-type macrophages, thus inhibiting the inflammatory responses. As a result, Ptn-CeO2 inhibits the reperfusion-induced neuronal apoptosis, relieves the infarct volume, reduces the neurological severity score, and improves cognitive function. Overall, these findings suggest that the prominent neuroprotective effect of the engineered Ptn-CeO2 has a significant neuroprotective effect and provides a potential therapeutic alternative for CIRI.

Customized Intranasal Hydrogel Delivering Methylene Blue Ameliorates Cognitive Dysfunction against Alzheimer's Disease

The accumulation of hyperphosphorylated tau protein aggregates is a key pathogenic event in Alzheimer's disease (AD) and induces mitochondrial dysfunction and reactive oxygen species overproduction. However, the treatment of AD remains challenging owning to the hindrance caused by the blood-brain barrier (BBB) and the complex pathology of AD. Nasal delivery represents an effective means of circumventing the BBB and delivering drugs to the brain. In this study, black phosphorus (BP) is used as a drug carrier, as well as an antioxidant, and loaded with a tau aggregation inhibitor, methylene blue (MB), to obtain BP-MB. For intranasal (IN) delivery, a thermosensitive hydrogel is fabricated by cross-linking carboxymethyl chitosan and aldehyde Pluronic F127 (F127-CHO) micelles. The BP-MB nanocomposite is incorporated into the hydrogel to obtain BP-MB@Gel. BP-MB@Gel could be injected intranasally, providing high nasal mucosal retention and controlled drug release. After IN administration, BP-MB is continuously released and delivered to the brain, exerting synergistic therapeutic effects by suppressing tau neuropathology, restoring mitochondrial function, and alleviating neuroinflammation, thus inducing cognitive improvements in mouse models of AD. These findings highlight a potential strategy for brain-targeted drug delivery in the management of the complex pathologies of AD.

Blood-Brain Barrier-Penetrating and Lesion-Targeting Nanoplatforms Inspired by the Pathophysiological Features for Synergistic Ischemic Stroke Therapy

Ischemic stroke is a dreadful vascular disorder that poses enormous threats to the public health. Due to its complicated pathophysiological features, current treatment options after ischemic stroke attack remains unsatisfactory. Insufficient drug delivery to ischemic lesions impeded by the blood-brain barrier (BBB) largely limits the therapeutic efficacy of most anti-stroke agents. Herein, inspired by the rapid BBB penetrability of 4T1 tumor cells upon their brain metastasis and natural roles of platelet in targeting injured vasculatures, a bio-derived nanojacket is developed by fusing 4T1 tumor cell membrane with platelet membrane, which further clothes on the surface of paeonol and polymetformin-loaded liposome to obtain biomimetic nanoplatforms (PP@PCL) for ischemic stroke treatment. The designed PP@PCL could remarkably alleviate ischemia-reperfusion injury by efficiently targeting ischemic lesion, preventing neuroinflammation, scavenging excess reactive oxygen species (ROS), reprogramming microglia phenotypes, and promoting angiogenesis due to the synergistic therapeutic mechanisms that anchor the pathophysiological characteristics of ischemic stroke. As a result, PP@PCL exerts desirable therapeutic efficacy in injured PC12 neuronal cells and rat model of ischemic stroke, which significantly attenuates neuronal apoptosis, reduces infarct volume, and recovers neurological functions, bringing new insights into exploiting promising treatment strategies for cerebral ischemic stroke management.

Neutrophil-Mimetic, ROS Responsive, and Oxygen Generating Nanovesicles for Targeted Interventions of Refractory Rheumatoid Arthritis

Rheumatoid arthritis (RA) is the most prevalent inflammatory joint disease worldwide, leading to irreversible disability and even mortality. Unfortunately, current treatment regimens fail to cure RA due to low therapeutic responses and off-target side effects. Herein, a neutrophil membrane-cloaked, natural anti-arthritic agent leonurine (Leo), and catalase (CAT) co-loaded nanoliposomal system (Leo@CAT@NM-Lipo) is constructed to remodel the hostile microenvironment for RA remission. Due to the inflammation tropism inherited from neutrophils, Leo@CAT@NM-Lipo can target and accumulate in the inflamed joint cavity where high-level ROS can be catalyzed into oxygen by CAT to simultaneously accelerate the drug release and alleviate hypoxia at the lesion site. Besides, the neutrophil membrane camouflaging also enhances the anti-inflammatory potentials of Leo@CAT@NM-Lipo by robustly absorbing pro-arthritogenic cytokines and chemokines. Consequently, Leo@CAT@NM-Lipo successfully alleviated paw swelling, reduced arthritis score, mitigated bone and cartilage damage, and reversed multiple organ dysfunctions in adjuvant-induced arthritis rats (AIA) rats by synergistic effects of macrophage polarization, inflammation resolution, ROS scavenging, and hypoxia relief. Furthermore, Leo@CAT@NM-Lipo manifested excellent biocompatibility both at the cellular and animal levels. Taken together, the study provided a neutrophil-mimetic and ROS responsive nanoplatform for targeted RA therapy and represented a promising paradigm for the treatment of a variety of inflammation-dominated diseases.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

Classification and application of metal-based nanoantioxidants in medicine and healthcare

Antioxidants play an important role in the prevention of oxidative stress and have been widely used in medicine and healthcare. However, natural antioxidants have several limitations such as low stability, difficult long-term storage, and high cost of large-scale production. Along with significant advances in nanotechnology, nanomaterials have emerged as a promising solution to improve the limitations of natural antioxidants because of their high stability, easy storage, time effectiveness, and low cost. Among various types of nanomaterials exhibiting antioxidant activity, metal-based nanoantioxidants show excellent reactivity because of the presence of an unpaired electron in their atomic structure. In this review, we summarize some novel metal-based nanoantioxidants and classify them into two main categories, namely chain-breaking and preventive antioxidant nanomaterials. In addition, the applications of antioxidant nanomaterials in medicine and healthcare are also discussed. This review provides a deeper understanding of the mechanisms of metal-based nanoantioxidants and a guideline for using these nanomaterials in medicine and healthcare.

Biofunctional lipid nanoparticles for precision treatment and prophylaxis of bacterial infections

The lack of bacterial-targeting function in antibiotics and their prophylactic usage have caused overuse of antibiotics, which lead to antibiotic resistance and inevitable long-term toxicity. To overcome these issues, we develop neutrophil-bacterial hybrid cell membrane vesicle (HMV)-coated biofunctional lipid nanoparticles (LNP@HMVs), which are designed to transport antibiotics specifically to bacterial cells at the infection site for the effective treatment and prophylaxis of bacterial infection. The dual targeting ability of HMVs to inflammatory vascular endothelial cells and homologous Gram-negative bacterial cells results in targeted accumulation of LNP@HMVs in the site of infections. LNP@HMVs loaded with the antibiotic norfloxacin not only exhibit enhanced activity against planktonic bacteria and bacterial biofilms in vitro but also achieve potent therapeutic efficacy in treating both systemic infection and lung infection. Furthermore, LNP@HMVs trigger the activation of specific humoral and cellular immunity to prevent bacterial infection. Together, LNP@HMVs provide a promising strategy to effectively treat and prevent bacterial infection.

Stepwise targeted strategies for improving neurological function by inhibiting oxidative stress levels and inflammation following ischemic stroke

Ischemia-reperfusion injury is caused by excessive production of reactive oxygen species (ROS) and inflammation accompanied by ischemic injury symptoms and blood-brain barrier (BBB) dysfunction. This causes neuronal damage, for which no effective treatments or drugs exist. Herein, we provided a stepwise targeted drug delivery strategy and successfully prepared multifunctional ORD@SHp@ANG nanoparticles (NPs) that consist of a stroke homing peptide (DSPE-PEG2000-SHp), BBB-targeting peptide (DSPE-PEG2000-ANG), and ROS-responsive Danshensu (salvianic acid A) chain self-assembly. ORD@SHp@ANG NPs effectively crossed the BBB by ANG peptide and selectively targeted the ischemic brain sites using stroke-homing peptide. The results showed that ORD@SHp@ANG NPs can effective at scavenging ROS, and protect SH-SY5Y cells from oxidative damage in vitro. Furthermore, ORD@SHp@ANG NPs showed excellent biocompatibility. These NPs recognized brain endothelial cells and crossed the BBB, regulated the transformation of microglia into the anti-inflammatory phenotype, and inhibited the production of inflammatory factors in a rat ischemia-reperfusion model, thereby reducing cerebral infarction, neuronal apoptosis and preserving BBB integrity. Sequencing revealed that ORD@SHp@ANG NPs promote cell proliferation, activate immune responses, suppress inflammatory responses, and ameliorate ischemic stroke. In conclusion, this study reports a simple and promising drug delivery strategy for managing ischemic stroke.

Immune cells: potential carriers or agents for drug delivery to the central nervous system

Drug delivery systems (DDS) have recently emerged as a promising approach for the unique advantages of drug protection and targeted delivery. However, the access of nanoparticles/drugs to the central nervous system (CNS) remains a challenge mainly due to the obstruction from brain barriers. Immune cells infiltrating the CNS in the pathological state have inspired the development of strategies for CNS foundation drug delivery. Herein, we outline the three major brain barriers in the CNS and the mechanisms by which immune cells migrate across the blood-brain barrier. We subsequently review biomimetic strategies utilizing immune cell-based nanoparticles for the delivery of nanoparticles/drugs to the CNS, as well as recent progress in rationally engineering immune cell-based DDS for CNS diseases. Finally, we discuss the challenges and opportunities of immune cell-based DDS in CNS diseases to promote their clinical development.

X-ray Activated Nanoprodrug for Visualization of Cortical Microvascular Alterations and NIR-II Image-Guided Chemo-Radiotherapy of Glioblastoma

The permeability of the highly selective blood-brain barrier (BBB) to anticancer drugs and the difficulties in defining deep tumor boundaries often reduce the effectiveness of glioma treatment. Thus, exploring the combination of multiple treatment modalities under the guidance of second-generation near-infrared (NIR-II) window fluorescence (FL) imaging is considered a strategic approach in glioma theranostics. Herein, a hybrid X-ray-activated nanoprodrug was developed to precisely visualize the structural features of glioma microvasculature and delineate the boundary of glioma for synergistic chemo-radiotherapy. The nanoprodrug comprised down-converted nanoparticle (DCNP) coated with X-ray sensitive poly(Se-Se/DOX-co-acrylic acid) and targeted Angiopep-2 peptide (DCNP@P(Se-DOX)@ANG). Because of its ultrasmall size and the presence of DOX, the nanoprodrug could easily cross BBB to precisely monitor and localize glioblastoma via intracranial NIR-II FL imaging and synergistically administer antiglioblastoma chemo-radiotherapy through specific X-ray-induced DOX release and radiosensitization. This study provides a novel and effective strategy for glioblastoma imaging and chemo-radiotherapy.

Cell Membrane Camouflaged Biomimetic Nanoparticles as a Versatile Platform for Brain Diseases Treatment

Although there are various advancements in biomedical in the past few decades, there are still challenges in the treatment of brain diseases. The main difficulties are the inability to deliver a therapeutic dose of the drug to the brain through the blood-brain barrier (BBB) and the serious side effects of the drug. Thus, it is essential to select biocompatible drug carriers and novel therapeutic tools to better enhance the effect of brain disease treatment. In recent years, biomimetic nanoparticles (BNPs) based on natural cell membranes, which have excellent biocompatibility and low immunogenicity, are widely used in the treatment of brain diseases to enable the drug to successfully cross the BBB and target brain lesions. BNPs can prolong the circulation time in vivo, are more conducive to drug aggregation in brain lesions. Cell membranes (CMs) from cancer cells (CCs), red blood cells (RBCs), white blood cells (WBCs), and so on are used as biomimetic coatings for nanoparticles (NPs) to achieve the ability to target, evade clearance, or stimulate the immune system. This review summarizes the application of different cell sources as BNPs coatings in the treatment of brain diseases and discusses the possibilities and challenges of clinical translation.

Enhanced "Electronic Tongue" for Dental Bacterial Discrimination and Elimination Based on a DNA-Encoded Nanozyme Sensor Array

Bacterial infections are the second leading cause of death around the world, especially those caused by delayed treatment and misdiagnosis. Therefore, rapid discrimination and effective elimination of multiple bacteria are of great importance for improving the survival rate in clinic. Herein, a novel colorimetric sensor array for bacterial discrimination and elimination is constructed using programmable DNA-encoded iron oxide nanoparticles (IONPs) as sensing elements. Utilizing differential interactions of bacteria on DNA-encoded IONPs, 11 kinds of dental bacteria and 6 kinds of proteins have been successfully identified by linear discriminant analysis (LDA). Moreover, the developed sensing system also performs well in the quantitative determination of individual bacteria and identification of bacterial mixtures. More importantly, the practicability of this sensing strategy is further verified by precise differentiation of blind and artificial saliva samples. Furthermore, the sensor array is used for efficiently killing multiple bacteria, demonstrating great potential in clinical prophylaxis and therapy.

Antioxidant nanozymes as next-generation therapeutics to free radical-mediated inflammatory diseases: A comprehensive review

Recent developments in exploring the biological enzyme mimicking properties in nanozymes have opened a separate avenue, which provides a suitable alternative to the natural antioxidants and enzymes. Due to high and tunable catalytic activity, low cost of synthesis, easy surface modification, and good biocompatibility, nanozymes have garnered significant research interest globally. Several inorganic nanomaterials have been investigated to exhibit catalytic activities of some of the key natural enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, peroxidase, and oxidase, etc. These nanozymes are used for diverse biomedical applications including therapeutics, imaging, and biosensing in various cells/tissues and animal models. In particular, inflammation-related diseases are closely associated with reactive oxygen and reactive nitrogen species, and therefore effective antioxidants could be excellent therapeutics due to their free radical scavenging ability. Although biological enzymes and other artificial antioxidants could perform well in scavenging the reactive oxygen and nitrogen species, however, suffer from several drawbacks such as the requirement of strict physiological conditions for enzymatic activity, limited stability in the environment beyond their optimum pH and temperature, and high cost of synthesis, purification, and storage make then unattractive for broad-spectrum applications. Therefore, this review systematically and comprehensively presents the free radical-mediated evolution of various inflammatory diseases (inflammatory bowel disease, mammary gland fibrosis, and inflammation, acute injury of the liver and kidney, mammary fibrosis, and cerebral ischemic stroke reperfusion) and their mitigation by various antioxidant nanozymes in the biological system. The mechanism of free radical scavenging by antioxidant nanozymes under in vitro and in vivo experimental models and catalytic efficiency comparison with corresponding natural enzymes has also been presented.

Machine-Learning-Assisted Nanozyme Design: Lessons from Materials and Engineered Enzymes

Nanozymes are nanomaterials that exhibit enzyme-like biomimicry. In combination with intrinsic characteristics of nanomaterials, nanozymes have broad applicability in materials science, chemical engineering, bioengineering, biochemistry, and disease theranostics. Recently, the heterogeneity of published results has highlighted the complexity and diversity of nanozymes in terms of consistency of catalytic capacity. Machine learning (ML) shows promising potential for discovering new materials, yet it remains challenging for the design of new nanozymes based on ML approaches. Alternatively, ML is employed to promote optimization of intelligent design and application of catalytic materials and engineered enzymes. Incorporation of the successful ML algorithms used in the intelligent design of catalytic materials and engineered enzymes can concomitantly facilitate the guided development of next-generation nanozymes with desirable properties. Here, recent progress in ML, its utilization in the design of catalytic materials and enzymes, and how emergent ML applications serve as promising strategies to circumvent challenges associated with time-expensive and laborious testing in nanozyme research and development are summarized. The potential applications of successful examples of ML-aided catalytic materials and engineered enzymes in nanozyme design are also highlighted, with special focus on the unified aims in enhancing design and recapitulation of substrate selectivity and catalytic activity.

Biosystem-Inspired Engineering of Nanozymes for Biomedical Applications

Nanozymes with intrinsic enzyme-mimicking activities have shown great potential to become surrogates of natural enzymes in many fields by virtue of their advantages of high catalytic stability, ease of functionalization, and low cost. However, due to the lack of predictable descriptors, most of the nanozymes reported in the past have been obtained mainly through trial-and-error strategies, and the catalytic efficacy, substrate specificity, as well as practical application effect under physiological conditions, are far inferior to that of natural enzymes. To optimize the catalytic efficacies and functions of nanozymes in biomedical settings, recent studies have introduced biosystem-inspired strategies into nanozyme design. In this review, recent advances in the engineering of biosystem-inspired nanozymes by leveraging the refined catalytic structure of natural enzymes, simulating the behavior changes of natural enzymes in the catalytic process, and mimicking the specific biological processes or living organisms, are introduced. Furthermore, the currently involved biomedical applications of biosystem-inspired nanozymes are summarized. More importantly, the current opportunities and challenges of the design and application of biosystem-inspired nanozymes are discussed. It is hoped that the studies of nanozymes based on bioinspired strategies will be beneficial for constructing the new generation of nanozymes and broadening their biomedical applications.

Rehabilitation training enhanced the therapeutic effect of calycosin on neurological function recovery of rats following spinal cord injury

BACKGROUND

Calycosin (CA), a flavonoids component, has demonstrated potential neuroprotection effects by inhibiting oxidative stress in spinal cord injury (SCI) models. This study aims to investigate the impact of combined rehabilitation training (RT) and calycosin therapy on neurological function following SCI, primarily by assessing changes in motor function recovery, neuronal survival, neuronal oxidative stress levels, and neural proliferation, in order to provide novel insights for the treatment of SCI.

MATERIALS AND METHODS

The SCI model was constructed by compressing the spinal cord using vascular clamps. Calycosin was injected intraperitoneally into the SCI model rats, and a group of 5 rats underwent RT. The motor function of rats after SCI was evaluated using the Basso Beattle Bresnaha (BBB) score and the inclined plate test. Histopathological changes were evaluated by NeuN immunohistochemistry, HE and Nissl staining. Apoptosis was detected by TUNEL staining. The antioxidant effect of combined treatment was assessed by measuring changes in oxidative stress markers after SCI. Western blot analysis was conducted to examine changes in Hsp90-Akt/ASK1-p38 pathway-related proteins. Finally, cell proliferation was detected by BrdU and Ki67 assays.

RESULTS

RT significantly improved the BBB score and angle of incline promoted by calycosin, resulting in enhanced motor function recovery in rats with SCI. Combining rehabilitation training with calycosin has a positive effect on morphological recovery. Similarly, combined RT enhanced the Nissl and NeuN staining signals of spinal cord neurons increased by calycosin, thereby increasing the number of neurons. TUNEL staining results indicated that calycosin treatment reduced the apoptosis signal in SCI, and the addition of RT further reduced the apoptosis. Moreover, RT combined with calycosin reduced oxidative stress by increasing SOD and GSH levels, while decreasing MDA, NO, ROS, and LDH expressions compared to the calycosin alone. RT slightly enhanced the effect of calycosin in activating Hsp90 and Akt and inhibiting the activation of ASK1 and p38, leading to enhanced inhibition of oxidative stress by calycosin. Additionally, the proliferation indexes (Ki67 and BrdU) assays showed that calycosin treatment alone increased both, whereas the combination treatment further promoted cell proliferation.

CONCLUSION

Our research findings demonstrate that rehabilitation training enhances the ability of calycosin to reduce oxidative stress, resulting in a decrease in neuronal apoptosis and an increase in proliferation, ultimately promoting neuronal survival.

Ferroptosis-Based Therapeutic Strategies toward Precision Medicine for Cancer

Ferroptosis is a type of iron-dependent programmed cell death characterized by the dysregulation of iron metabolism and the accumulation of lipid peroxides. This nonapoptotic mode of cell death is implicated in various physiological and pathological processes. Recent findings have underscored its potential as an innovative strategy for cancer treatment, particularly against recalcitrant malignancies that are resistant to conventional therapies. This article focuses on ferroptosis-based therapeutic strategies for precision cancer treatment, covering the molecular mechanisms of ferroptosis, four major types of ferroptosis inducers and their inhibitory effects on diverse carcinomas, the detection of ferroptosis by fluorescent probes, and their implementation in image-guided therapy. These state-of-the-art tactics have manifested enhanced selectivity and efficacy against malignant carcinomas. Given that the administration of ferroptosis in cancer therapy is still at a burgeoning stage, some major challenges and future perspectives are discussed for the clinical translation of ferroptosis into precision cancer treatment.

A Pluripotential Neutrophil-Mimic Nanovehicle Modulates Immune Microenvironment with Targeted Drug Delivery for Augmented Antitumor Chemotherapy

The limited therapeutic outcomes and severe systemic toxicity of chemotherapy remain major challenges to the current clinical antitumor therapeutic regimen. Tumor-targeted drug delivery that diminishes the undifferentiated systemic distribution is a practical solution to ameliorating systemic toxicity. However, the tumor adaptive immune microenvironment still poses a great threat that compromises the therapeutic efficacy of chemotherapy by promoting the tolerance of the tumor cells. Herein, a pluripotential neutrophil-mimic nanovehicle (Neutrosome(L)) composed of an activated neutrophil membrane-incorporated liposome is proposed to modulate the immune microenvironment and synergize antitumor chemotherapy. The prominent tumor targeting capability inherited from activated neutrophils and the improved tumor penetration ability of Neutrosome(L) enable considerable drug accumulation in tumor tissues (more than sixfold that of free drug). Importantly, Neutrosome(L) can modulate the immune microenvironment by restricting neutrophil infiltration in tumor tissue, which may be attributed to the neutralization of inflammatory cytokines, thus potentiating antitumor chemotherapy. As a consequence, the treatment of cisplatin-loaded Neutrosome(L) performs prominent tumor suppression effects, reduces systemic drug toxicity, and prolongs the survival period of tumor-bearing mice. The pluripotential neutrophil-mimic nanovehicle proposed in this study can not only enhance the tumor accumulation of chemotherapeutics but also modulate the immune microenvironment, providing a compendious strategy for augmented antitumor chemotherapy.

Cell Membrane-Coated Nanoparticles for Precision Medicine: A Comprehensive Review of Coating Techniques for Tissue-Specific Therapeutics

Nanoencapsulation has become a recent advancement in drug delivery, enhancing stability, bioavailability, and enabling controlled, targeted substance delivery to specific cells or tissues. However, traditional nanoparticle delivery faces challenges such as a short circulation time and immune recognition. To tackle these issues, cell membrane-coated nanoparticles have been suggested as a practical alternative. The production process involves three main stages: cell lysis and membrane fragmentation, membrane isolation, and nanoparticle coating. Cell membranes are typically fragmented using hypotonic lysis with homogenization or sonication. Subsequent membrane fragments are isolated through multiple centrifugation steps. Coating nanoparticles can be achieved through extrusion, sonication, or a combination of both methods. Notably, this analysis reveals the absence of a universally applicable method for nanoparticle coating, as the three stages differ significantly in their procedures. This review explores current developments and approaches to cell membrane-coated nanoparticles, highlighting their potential as an effective alternative for targeted drug delivery and various therapeutic applications.

The Landscape of Biomimetic Nanovesicles in Brain Diseases

Brain diseases, such as brain tumors, neurodegenerative diseases, cerebrovascular diseases, and brain injuries, are caused by various pathophysiological changes, which pose a serious health threat. Brain disorders are often difficult to treat due to the presence of the blood-brain barrier (BBB). Biomimetic nanovesicles (BNVs), including endogenous extracellular vesicles (EVs) derived from various cells and artificial nanovesicles, possess the ability to penetrate the BBB and thus can be utilized for drug delivery to the brain. BNVs, especially endogenous EVs, are widely distributed in body fluids and usually carry various disease-related signal molecules such as proteins, RNA, and DNA, and may also be analyzed to understand the etiology and pathogenesis of brain diseases. This review covers the exhaustive classification and characterization of BNVs and pathophysiological roles involved in various brain diseases, and emphatically focuses on nanotechnology-integrated BNVs for brain disease theranostics, including various diagnosis strategies and precise therapeutic regulations (e.g., immunity regulation, disordered protein clearance, anti-neuroinflammation, neuroregeneration, angiogenesis, and the gut-brain axis regulation). The remaining challenges and future perspectives regarding the nanotechnology-integrated BNVs for the diagnosis and treatment of brain diseases are also discussed and outlined.

Bone-Targeted Biomimetic Nanogels Re-Establish Osteoblast/Osteoclast Balance to Treat Postmenopausal Osteoporosis

Insufficient bone formation and excessive bone resorption caused by estrogen deficiency are the major factors resulting in the incidence of postmenopausal osteoporosis (PMOP). The existing drugs usually fail to re-establish the osteoblast/osteoclast balance from both sides and generate side-effects owing to the lack of bone-targeting ability. Here, engineered cell-membrane-coated nanogels PNG@mR&C capable of scavenging receptor activator of nuclear factor-κB ligand (RANKL) and responsively releasing therapeutic PTH 1-34 in the bone microenvironment are prepared from RANK and CXCR4 overexpressed bone mesenchymal stem cell (BMSC) membrane-coated chitosan biopolymers. The CXCR4 on the coated-membranes confer bone-targeting ability, and abundant RANK effectively absorb RANKL to inhibit osteoclastogenesis. Meanwhile, the release of PTH 1-34 triggered by osteoclast-mediated acid microenvironment promote osteogenesis. In addition, the dose and frequency are greatly reduced due to the smart release property, prolonged circulation time, and bone-specific accumulation. Thus, PNG@mR&C exhibits satisfactory therapeutic effects in the ovariectomized (OVX) mouse model. This study provides a new paradigm re-establishing the bone metabolic homeostasis from multitargets and shows great promise for the treatment of PMOP.

Multifunctional nanozymes for disease diagnosis and therapy

The development of nanotechnology has brought about groundbreaking advancements in diseases' diagnostics and therapeutics. Among them, multifunctional nanomaterials with enzyme-like activities (i.e., nanozymes) featured with high stability, large surface area for bioconjugation, and easy storage, offer unprecedented opportunities for disease diagnostics and treatment. Recent years have witnessed the great progress of nanozyme-based theranostics. To highlight these achievements, this review first introduces the recent advancements on nanozymes in biosensing and diagnostics. Then, it summarizes the applications of nanozymes in therapeutics including anti-tumor and antibacterial treatment, anti-inflammatory treatment, and other diseases treatment. In addition, several targeted strategies to improve the therapeutic efficacy of nanozyme are discussed. Finally, the opportunities and challenges in the field of diagnosis and therapy are summarized.

Engineered Biomimetic Nanovesicles Based on Neutrophils for Hierarchical Targeting Therapy of Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome (ARDS) is a clinically severe respiratory disease that causes severe medical and economic burden. To improve therapeutic efficacy, effectively targeting delivery to the inflamed lungs and inflamed cells remains an ongoing challenge. Herein, we designed engineered biomimetic nanovesicles (DHA@ANeu-DDAB) by fusion of lung-targeting functional lipid, neutrophil membrane containing activated β2 integrins, and the therapeutic lipid, docosahexaenoic acid (DHA). By the advantage of lung targeting lipid and β2 integrin targeting adhesion, DHA@ANeu-DDAB can first target lung tissue and further target inflammatory vascular endothelial cells, to achieve "tissue first, cell second" hierarchical delivery. In addition, the β2 integrins in DHA@ANeu-DDAB could bind to the intercellular cell adhesion molecule-1/2 (ICAM-1/2) ligand on the endothelium in the inflamed blood vessels, thus inhibiting neutrophils' infiltration in the blood circulation. DHA administration to inflamed lungs could effectively regulate macrophage phenotype and promote its anti-inflammatory activity via enhanced biosynthesis of specialized pro-resolving mediators. In the lipopolysaccharide-induced ARDS mouse model, DHA@ANeu-DDAB afforded a comprehensive and efficient inhibition of lung inflammation and promoted acute lung damage repair. Through mimicking physiological processes, these engineered biomimetic vesicles as a delivery system possess good potential in targeting therapy for ARDS.

A Novel Endoplasmic Reticulum-Targeted Metal-Organic Framework-Confined Ruthenium (Ru) Nanozyme Regulation of Oxidative Stress for Central Post-Stroke Pain

Central post-stroke pain (CPSP) is a chronic neuropathic pain caused by cerebrovascular lesion or disfunction after stroke. Convincing evidence suggest that excessive reactive oxygen species (ROS), generated matrix metalloproteinase (MMPs) and neuroinflammation are largely involved in the development of pain. In this study, an effective strategy is reported for treating pain hypersensitivity using an endoplasmic reticulum (ER)-targeted metal-organic framework (MOF)-confined ruthenium (Ru) nanozyme. The Ru MOF is coated with a p-dodecylbenzene sulfonamide (p-DBSN) modified liposome with endoplasmic reticulum-targeted function. The experimental results reveals that ROS, Emmprin, MMP-2, and MMP-9 are upregulated in the brain of CPSP mice, along with the elevated expression of inflammation markers such as TNF-α and IL-6. Compared to vehicle, one-time intravenous administration of ER-Ru MOF significantly reduces mechanical hypersensitivity after CPSP for three days. Overall, ER-Ru MOF system can inhibit oxidative stress in the brain tissues of CPSP model, reduce MMPs expression, and suppress neuroinflammation response-induced injury, resulting in satisfactory prevention and effective treatment of CPSP during a hemorrhagic stroke. The ER-Ru MOF is expected to be useful for the treatment of neurological diseases associated with the vicious activation of ROS, based on the generality of the approach used in this study.

Cytoplasmic Escape of Mitochondrial DNA Mediated by Mfn2 Downregulation Promotes Microglial Activation via cGas-Sting Axis in Spinal Cord Injury

Neuroinflammation is associated with poor outcomes in patients with spinal cord injury (SCI). Recent studies have demonstrated that stimulator of interferon genes (Sting) plays a key role in inflammatory diseases. However, the role of Sting in SCI remains unclear. In the present study, it is found that increased Sting expression is mainly derived from activated microglia after SCI. Interestingly, knockout of Sting in microglia can improve the recovery of neurological function after SCI. Microglial Sting knockout restrains the polarization of microglia toward the M1 phenotype and alleviates neuronal death. Furthermore, it is found that the downregulation of mitofusin 2 (Mfn2) expression in microglial cells leads to an imbalance in mitochondrial fusion and division, inducing the release of mitochondrial DNA (mtDNA), which mediates the activation of the cGas-Sting signaling pathway and aggravates inflammatory response damage after SCI. A biomimetic microglial nanoparticle strategy to deliver MASM7 (named MSNs-MASM7@MI) is established. In vitro, MSNs-MASM7@MI showed no biological toxicity and effectively delivered MASM7. In vivo, MSNs-MASM7@MI improves nerve function after SCI. The study provides evidence that cGas-Sting signaling senses Mfn2-dependent mtDNA release and that its activation may play a key role in SCI. These findings provide new perspectives and potential therapeutic targets for SCI treatment.

Single-atom nanozymes with peroxidase-like activity: A review

Single-atom nanozymes (SANs) are nanomaterials-based nanozymes with atomically dispersed enzyme-like active sites. SANs offer improved as well as tunable catalytic activity. The creation of extremely effective SANs and their potential uses have piqued researchers' curiosity due to their advantages of cheap cost, variable catalytic activity, high stability, and large-scale production. Furthermore, SANs with uniformly distributed active centers and definite coordination structures offer a distinctive opportunity to investigate the structure-activity correlation and control the geometric and electrical features of metal centers. SANs have been extensively explored in photo-, thermal-, and electro-catalysis. However, SANs suffer from the following disadvantages, such as efficiency, non-mimicking of the 3-D complexity of natural enzymes, limited and narrow range of artificial SANs, and biosafety aspects. Among a quite limited range of artificial SANs, the peroxidase action of SANs has attracted significant research attention in the last five years with the aim of producing reactive oxygen species for use in cancer therapy, and water treatment among many other applications. In this review, we explore the recent progress of different SANs as peroxidase mimics, the role of the metal center in enzymatic activity, possible prospects, and underlying limitations in real-time applications.

Spatiotemporally sequential delivery of biomimetic liposomes potentiates glioma chemotherapy

As one of the most challenging cancers, glioma still lacks efficient therapeutic treatment in clinics. The dilemmas of nanodrug-based therapies for glioma are due not only the limited permeability of the blood-brain barrier (BBB) but also the deficiency of targeting tumor lesions. Thus, spatiotemporally sequential delivery of therapeutics from BBB-crossing to glioma accumulation is considered a strategy to obtain better outcomes. Here, we developed a biomimetic chemotherapy nanodrug composed of the hybrid membrane envelope of U87 cell membranes and RAW264.7 cell membranes, and the core of paclitaxel (PTX)-loaded liposome (PTX@C-MMCL). In the research, PTX@C-MMCL showed superior ability to cross the BBB via RAW264.7 cell membranes and accurate targeting to the brain tumor lesions relying on the homotypic targeting capacity of U87 cell membranes. Furthermore, PTX@C-MMCL can maintain a prolonged circulation in vivo. Importantly, PTX@C-MMCL effectively inhibited the development of glioma. Conclusively, our biomimetic nanodrug holds great potential for brain tumor targeting therapy.

Cell Membrane-Camouflaged Nanoparticles Mediated Nucleic Acids Delivery

Nucleic acids have emerged as promising therapeutic agents for many diseases because of their potential in modulating gene expression. However, the delivery of nucleic acids remains a significant challenge in gene therapy. Although viral vectors have shown high transfection efficiency, concerns regarding teratogenicity or carcinogenicity have been raised. Non-viral vehicles, including cationic polymers, liposomes, and inorganic materials possess advantages in terms of safety, ease of preparation, and low cost. Nevertheless, they also face limitations related to immunogenicity, quick clearance in vivo, and lack of targeting specificity. On the other hand, bioinspired strategies have shown increasing potential in the field of drug delivery, yet there is a lack of comprehensive reviews summarizing the rapid development of bioinspired nanoparticles based on the cell membrane camouflage to construct the nucleic acids vehicles. Herein, we enumerated the current difficulties in nucleic acid delivery with various non-viral vehicles and provided an overview of bioinspired strategies for nucleic acid delivery.

Cell Membrane-Derived Nanovehicles for Targeted Therapy of Ischemic Stroke: From Construction to Application

Ischemic stroke (IS) is a prevalent form of stroke and a leading cause of mortality and disability. Recently, cell membrane-derived nanovehicles (CMNVs) derived from erythrocytes, thrombocytes, neutrophils, macrophages, neural stem cells, and cancer cells have shown great promise as drug delivery systems for IS treatment. By precisely controlling drug release rates and targeting specific sites in the brain, CMNVs enable the reduction in drug dosage and minimization of side effects, thus significantly enhancing therapeutic strategies and approaches for IS. While there are some reviews regarding the applications of CMNVs in the treatment of IS, there has been limited attention given to important aspects such as carrier construction, structural design, and functional modification. Therefore, this review aims to address these key issues in CMNVs preparation, structural composition, modification, and other relevant aspects, with a specific focus on targeted therapy for IS. Finally, the challenges and prospects in this field are discussed.

High rapamycin-loaded hollow mesoporous Prussian blue nanozyme targets lesion area of spinal cord injury to recover locomotor function

Scavenging free radicals and reducing inflammatory reaction to relieve the secondary damage are important issues in the spinal cord injury (SCI) therapeutic strategy. Nanozymes attract more attention in the drug development of SCI due to the high stability, long-lasting catalytic capacity, and multienzyme-like properties. Herein, we constructed a Rapamycin (Rapa)-loaded and hollow mesoporous Prussian blue (HMPB)-based nanozyme (RHPAzyme) to realize the combined antioxidation and anti-inflammation combination therapy of SCI. Furthermore, activated cell penetrating peptide (ACPP) is modified onto nanozyme to endow the effectively ability of lesion area-targeting. This RHPAzyme exhibits ROS scavenging capacity with the transformation of Fe2+/Fe3+ valance and cyanide group of HMPB to achieve multienzyme-like activity. As expected, RHPAzyme scavenges the ROS overproduction and reduces inflammation in oxygen-glucose deprivation (OGD)-induced damage via inhibiting MAPK/AKT signaling pathway. Furtherly, RHPAzyme exhibits the combined antioxidant and anti-inflammatory activity in vivo, which can effectively alleviate neuronal damage and promote motor function recovery in SCI mice. Overall, this study demonstrates the RHPAzyme induces an effective treatment of SCI by inhibiting oxygen-mediated cell apoptosis and suppressing inflammation-induced injury, thus reduces the nervous impairment and promotes motor function recovery.

Biomimetic nanoparticles in ischemic stroke therapy

Abstract

Ischemic stroke is one of the most severe neurological disorders with limited therapeutic strategies. The utilization of nanoparticle drug delivery systems is a burgeoning field and has been widely investigated. Among these, biomimetic drug delivery systems composed of biogenic membrane components and synthetic nanoparticles have been extensively highlighted in recent years. Biomimetic membrane camouflage presents an effective strategy to prolong circulation, reduce immunogenicity and enhance targeting. For one thing, biomimetic nanoparticles reserve the physical and chemical properties of intrinsic nanoparticle. For another, the biological functions of original source cells are completely inherited. Compared to conventional surface modification methods, this approach is more convenient and biocompatible. In this review, membrane-based nanoparticles derived from different donor cells were exemplified. The prospect of future biomimetic nanoparticles in ischemic stroke therapy was discussed.

Graphic abstract

Multifunctional cell membranes-based nano-carriers for targeted therapies: a review of recent trends and future perspective

Nanotechnology has ignited a transformative revolution in disease detection, prevention, management, and treatment. Central to this paradigm shift is the innovative realm of cell membrane-based nanocarriers, a burgeoning class of biomimetic nanoparticles (NPs) that redefine the boundaries of biomedical applications. These remarkable nanocarriers, designed through a top-down approach, harness the intrinsic properties of cell-derived materials as their fundamental building blocks. Through shrouding themselves in natural cell membranes, these nanocarriers extend their circulation longevity and empower themselves to intricately navigate and modulate the multifaceted microenvironments associated with various diseases. This comprehensive review provides a panoramic view of recent breakthroughs in biomimetic nanomaterials, emphasizing their diverse applications in cancer treatment, cardiovascular therapy, viral infections, COVID-19 management, and autoimmune diseases. In this exposition, we deliver a concise yet illuminating overview of the distinctive properties underpinning biomimetic nanomaterials, elucidating their pivotal role in biomedical innovation. We subsequently delve into the exceptional advantages these nanomaterials offer, shedding light on the unique attributes that position them at the forefront of cutting-edge research. Moreover, we briefly explore the intricate synthesis processes employed in creating these biomimetic nanocarriers, shedding light on the methodologies that drive their development.

Advanced targeted drug delivery by bioengineered white blood cell-membrane camouflaged nanoparticulate delivery nanostructures

Targeted drug delivery has emerged as a pivotal approach within precision medicine, aiming to optimize therapeutic efficacy while minimizing systemic side effects. Leukocyte membrane coated nanoparticles (NPs) have attracted a lot of interest as an effective approach for delivering targeted drugs, capitalizing on the natural attributes of leukocytes to achieve site-specific accumulation, and heightened therapeutic outcomes. An overview of the present state of the targeted medication delivery research is given in this review. Notably, Leukocyte membrane-coated NPs offer inherent advantages such as immune evasion, extended circulation half-life, and precise homing to inflamed or diseased tissues through specific interactions with adhesion molecules. leukocyte membrane-coated NPs hold significant promise in advancing targeted drug delivery for precision medicine. As research progresses, they are anticipated to contribute to improved therapeutic outcomes, enabling personalized and effective treatments for a wide range of diseases and conditions. The review covers the method of preparation, characterization, and biological applications of leucocytic membrane coated NPs. Further, patents related factors, gap of translation from laboratory to clinic, and future prospective were discussed in detail. Overall, the review covers extensive literature to establish leucocytic membrane NPs for targeted drug delivery.