Comprehensive Insights into the Multi-Antioxidative Mechanisms of Melanin Nanoparticles and Their Application To Protect Brain from Injury in Ischemic Stroke

Natural melanin: from biological functions to biofunctionalized nanoparticles in advanced biomedicine

Melanin nanoparticles (MNPs) are multifunctional, bioinspired nanomaterials that have become a versatile platform for biomedical and technological applications due to their unique physicochemical properties. MNPs, derived from natural or synthetic melanin precursors, are distinguished by their ease of synthesis, low toxicity, and excellent biocompatibility, making them highly promising for applications in stimuli-responsive drug delivery, high-resolution medical imaging, real-time tumor theranostics, and targeted photothermal therapy. This review offers an in-depth overview of recent progress in the sources, synthesis methods, characterization techniques, and diverse applications of MNPs. Their inherent antioxidant properties, effectiveness in stimuli-responsive drug delivery, high photothermal conversion efficiency, and strong biocompatibility highlight their potential as promising agents for cancer treatment, targeted nanomedicine, and real-time diagnostic imaging. Furthermore, the ability of MNPs to integrate both therapeutic and diagnostic functions (theranostics) offers a promising solution to key challenges in precision medicine. This review emphasizes the growing importance of sustainable, low-toxicity nanomaterials, especially in growing global health challenges such as drug-resistant cancers and neurodegenerative diseases. By combining insights from materials science, nanotechnology, and biomedicine, this work highlights the transformative potential of MNPs while addressing key challenges and outlining future research directions.

Advances of functional nanomaterials as either therapeutic agents or delivery systems in the treatment of periodontitis

Periodontitis is a common chronic inflammatory disease primarily caused by pathogenic microorganisms in the oral cavity. Without appropriate treatments, it may lead to the gradual destruction of the supporting tissues of the teeth. While current treatments can alleviate symptoms, they still have limitations, particularly in eliminating pathogenic bacteria, promoting periodontal tissue regeneration, and avoiding antibiotic resistance. In recent years, functional nanomaterials have shown great potential in the treatment of periodontitis due to their unique physicochemical and biological properties. This review summarizes various functionalization strategies of nanomaterials and explores their potential applications in periodontitis treatment, including metal-based nanoparticles, carbon nanomaterials, polymeric nanoparticles, and exosomes. The mechanisms and advances in antibacterial effects, immune regulation, reactive oxygen species (ROS) scavenging, and bone tissue regeneration are discussed in detail. In addition, the challenges and future directions of applying nanomaterials in periodontitis therapy are also discussed.

Hybrid Se/melanin-like nanoparticles as ROS quenchers and inhibitors of amyloid aggregation

Hybrid selenium/melanin-like nanoparticles offer different therapeutic strategies against amyloid aggregation. In this study, novel Se-based nanostructures are synthesized, characterized, and preliminarily employed as modulators of amyloid aggregation. In detail, two types of Se NPs are tested: one containing only Se(0), named Se NPs, and the second hybrid Se/melanin structures, indicated as SeMel NPs. Advanced biophysical and spectroscopic analyses elucidate the structures of NPs and the mechanistic underpinnings of the inhibition of aggregation of two protein fragments employed as amyloid models, Aβ21-40 and NPM1264-277. Both NPs are investigated for their antioxidant and superoxide dismutase (SOD)-like activity, as well as for their colloidal stability through dynamic light scattering (DLS) and ζ-potential measurements. ThT and SEM experiments demonstrate their ability to suppress amyloid aggregation, while far-UV circular dichroism (CD) spectroscopy indicates secondary structure alterations upon nanoparticle interaction, revealing a shift from β-sheet-rich conformations towards α-helical intermediates. Finally, SeMel NPs demonstrate cytocompatibility with SH-SY5Y cells and an effective mitigation of the cytotoxic effects of the amyloid models. These findings position hybrid Se-melanin NPs as promising agents for targeted amyloid therapeutics.

Nanobiotechnologies for stroke treatment

Stroke has brought about a poor quality of life for patients and a substantial societal burden with high morbidity and mortality. Thus, the efficient stroke treatment has always been the hot topic in the research of medicine. In the past decades, nanobiotechnologies, including natural exosomes and artificial nanomaterials, have been a focus of attention for stroke treatment due to their inherent advantages, such as facile blood - brain barrier traversal and high drug encapsulation efficiency. Recently, thanks to the rapid development of nanobiotechnologies, more and more efforts have been made to study the therapeutic effects of exosomes and artificial nanomaterials as well as relevant mechanisms in stroke treatment. Herein, from recent studies and articles, the application of natural exosomes and artificial nanomaterials in stroke treatment are summarized. And their prospects of clinical translation and future development are also discussed in further detail.

Advancements of ROS-based biomaterials for sensorineural hearing loss therapy

Sensorineural hearing loss (SNHL) represents a substantial global health challenge, primarily driven by oxidative stress-induced damage within the auditory system. Excessive reactive oxygen species (ROS) play a pivotal role in this pathological process, leading to cellular damage and apoptosis of cochlear hair cells, culminating in irreversible hearing impairment. Recent advancements have introduced ROS-scavenging biomaterials as innovative, multifunctional platforms capable of mitigating oxidative stress. This comprehensive review systematically explores the mechanisms of ROS-mediated oxidative stress in SNHL, emphasizing etiological factors such as aging, acoustic trauma, and ototoxic medication exposure. Furthermore, it examines the therapeutic potential of ROS-scavenging biomaterials, positioning them as promising nanomedicines for targeted antioxidant intervention. By critically assessing recent advances in biomaterial design and functionality, this review thoroughly evaluates their translational potential for clinical applications. It also addresses the challenges and limitations of ROS-neutralizing strategies, while highlighting the transformative potential of these biomaterials in developing novel SNHL treatment modalities. This review advocates for continued research and development to integrate ROS-scavenging biomaterials into future clinical practice, aiming to address the unmet needs in SNHL management and potentially revolutionize the treatment landscape for this pervasive health issue.

Management of ROS and Regulatory Cell Death in Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion injury (MIRI) is fatal to patients, leading to cardiomyocyte death and myocardial remodeling. Reactive oxygen species (ROS) and oxidative stress play important roles in MIRI. There is a complex crosstalk between ROS and regulatory cell deaths (RCD) in cardiomyocytes, such as apoptosis, pyroptosis, autophagy, and ferroptosis. ROS is a double-edged sword. A reasonable level of ROS maintains the normal physiological activity of myocardial cells. However, during myocardial ischemia-reperfusion, excessive ROS generation accelerates myocardial damage through a variety of biological pathways. ROS regulates cardiomyocyte RCD through various molecular mechanisms. Targeting the removal of excess ROS has been considered an effective way to reverse myocardial damage. Many studies have applied antioxidant drugs or new advanced materials to reduce ROS levels to alleviate MIRI. Although the road from laboratory to clinic has been difficult, many scholars still persevere. This article reviews the molecular mechanisms of ROS inhibition to regulate cardiomyocyte RCD, with a view to providing new insights into prevention and treatment strategies for MIRI.

Removing Barriers to Tumor 'Oxygenation': Depleting Glutathione Nanozymes in Cancer Therapy

Nanozymes are nanomaterials capable of mimicking natural enzyme catalysis in the complex biological environment of the human body. Due to their good stability and strong catalytic properties, nanozymes are widely used in various fields of biomedicine. Among them, nanozymes that trigger intracellular reactive oxygen species (ROS) levels for cancer therapy have gained significant attention. However, the 'explosion' of ROS in tumor cells was prevented by the high levels of glutathione (GSH) in the tumor microenvironment (TME). GSH, a prominent endogenous antioxidant, increases the resistance of tumor cells to oxidative stress by scavenging ROS. Certain nanozymes can deplete intracellular GSH levels by mimicking GSH oxidase (GSHOx), GSH peroxidase (GPx) or by interfering with the reduction of oxidized glutathione (GSSG). On the one hand, elevated the level of intracellular ROS and induced lipid peroxidation reaction leading to ferroptosis. On the other hand, it creates favorable conditions for the treatment of tumors with photodynamic therapy (PDT), sonodynamic therapy (SDT), chemodynamical therapy (CDT) and targeted therapy. In this paper, we present a comprehensive analysis of GSH-depleting nanozymes reported in recent years, including classification, mechanism, responsiveness to TME and their roles in cancer therapy, and look forward to future applications and developments.

Therapeutic potential of Polydopamine-Coated selenium nanoparticles in Osteoarthritis treatment

Osteoarthritis (OA) affects millions globally, with its prevalence expected to rise due to an aging population. Selenium nanoparticles (SeNPs) have shown therapeutic potential, and polydopamine (PDA) coatings on nanoparticles offered additional benefits, including enhanced biocompatibility, antioxidant properties, and anti-inflammatory effects. However, while SeNPs and PDA have demonstrated efficacy in several disease models, their role in OA remains underexplored. This study aimed to evaluate the therapeutic effects of PDA-coated SeNPs in the treatment of OA. We developed PDA-coated SeNPs (PDA-SeNP) to improve Reactive Oxygen Species (ROS) control and evaluated their anti-inflammatory and cartilage-regenerative effects in both in vitro and in vivo models of OA. Transmission electron microscopy confirmed that the sizes of PDA-SeNPs was 203 ± 11 nm, with PDA coatings of approximately 12 ± 2 nm on the SeNPs. In vitro, treatment with PDA-SeNPs significantly enhanced the expression of cartilage-regeneration markers while reducing inflammatory marker levels in chondrocytes. For the in vivo analysis, OA was induced by injecting monoiodoacetate into the knee joints of rats. Four weeks after treatment with phosphate-buffered saline (PBS, n = 6), SeNPs (n = 6), or PDA-SeNPs (n = 6), the incapacitance test demonstrated improved weight-bearing capacity in the SeNP and PDA-SeNP groups compared to the PBS control. Gross morphological assessment and histological analysis revealed that PDA-SeNPs mitigated cartilage damage more effectively than SeNPs alone. These findings suggest that PDA-SeNPs promote cartilage repair, enhance extracellular matrix synthesis, and reduce knee pain in OA, establishing them as promising candidates for future OA treatment.

Inflammation Targeting and Responsive Multifunctional Drug-Delivery Nanoplatforms for Combined Therapy of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by persistent inflammation, joint swelling, pain, and progressive joint destruction. Methotrexate (MTX) is the standard first-line treatment for RA, but its clinical application is hindered by poor water solubility and non-specific delivery. In this work, a multifunctional drug-delivery nanoplatform that targets both macrophages and tumor necrosis factor α (TNFα) is developed to enhance the therapeutic efficacy of MTX in RA. The nanoplatform consists of folic acid (FA, for macrophage targeting) and a TNFα-specific Aptamer (TNFα-Apt), facilitating a dual-targeting strategy that significantly improves the accumulation of MTX at the sites of RA lesions (≈3.5-fold). Moreover, the manganese dioxide (MnO₂) and polydopamine (PDA) coatings on the nanoplatform effectively scavenge reactive oxygen species (ROS), generate oxygen, and promote the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2 macrophages. This shift in macrophage polarization restores the expression of key inflammatory cytokines, improving the local inflammatory microenvironment. Ultimately, the nanoplatform significantly ameliorates the inflammation and joint damage in a collagen-induced arthritis (CIA) model, suggesting that this multi-target combination therapy holds considerable potential for the treatment of RA in vivo.

Stimuli-Responsive Nodal Dual-Drug Polymer Nanoparticles for Cancer Therapy

Background

Polymeric drug delivery systems (DDSs) have gained significant attention in cancer therapy. However, these systems often respond to a single biological stimulus in tumor tissues or cells, limiting their effectiveness. While multi-sensitive DDSs improve therapeutic precision, their complex synthesis involving multi-step modifications remains challenging. Developing functionally integrated and simplified multiple stimuli-responsive DDSs is crucial to addressing tumor diversity and enhancing treatment efficacy.

Methods and Results

Here, we develop a dual-sensitive nodal dual-drug polymer nanoparticle (DDPoly NP) system for cancer therapy. This system combines a platinum(IV) prodrug (Cisplatin(IV)) with Demehylcantharidin (DMC) to create a dual-drug molecule (DDM). Then DDM is conjugated with methoxypolyethylene glycol (MPEG), forming a nodal dual-drug polymer (DDPoly). The amphiphilic polymer is capable of self-assembling into nanoparticles (DDPoly NPs) when in aqueous solution. The drug release experiments displayed that lower pH and reductive conditions simulating tumor microenvironment promoted the release of Cisplatin and DMC. Cytotoxicity studies demonstrated that DDPoly NPs exhibited superior anti-cancer activity compared to the single-drug system (SDPoly NPs). The IC50 values of DDPoly NPs against A549 cells (15.37 μM) and HeLa cells (17.05 μM) were significantly lower than those observed for SDPoly NPs, which were 40.48 μM for A549 cells and 38.11 μM for HeLa cells, respectively.

Conclusion

The study developed dual stimuli-responsive DDPoly NPs based on acid- and reduction-sensitive DDM, enabling tumor-specific activation without additional responsive components. DDPoly NPs triggered Pt(II) release via reduction and generated DMC through acid hydrolysis. The synergistic effect of DDPoly NPs lies in that DMC could inhibit the expression of serine/threonine protein phosphatase 2A (PP2A) and further elevate the expression of hyper-phosphorylated Akt (pAKt), thus blocking DNA repair to enhance Pt(II)-induced apoptosis. DDPoly NPs showed enhanced anti-cancer efficacy against cancer cells compared to SDPoly NPs, highlighting its potential for nanomedicine development.

Self-disassembling nanoparticles as oral nanotherapeutics targeting intestinal microenvironment

Inspired by the survival strategies of pyomelanin-producing microbes, we synthesize pyomelanin nanoparticles (PMNPs) from homogentisic acid- γ-lactone via auto-oxidation and investigate their biomedical potential. PMNPs possess distinct physicochemical properties, including reactive oxygen species scavenging and microenvironment-responsive self-disassembly. Under intestinal conditions, PMNPs self-disassemble and penetrate the nanoscale pores of the mucin layer. In an inflammatory bowel disease model, orally administered PMNPs withstand gastric acidity and, in their solubilized form, interact with macrophages and epithelial cells. They significantly reduce reactive oxygen species levels, exert anti-inflammatory effects, and restore gut microbiota composition. Compared to conventional nanoparticles and 5-aminosalicylic acid, PMNPs exhibit greater therapeutic efficacy. Clinical symptoms and intestinal inflammation are alleviated, and the gut microbiota is restored to near-normal levels. These findings underscore the therapeutic potential of PMNPs for inflammatory bowel disease treatment and suggest broader biomedical applications.

Multienzyme active melanin nanodots for antioxidant-immunomodulatory therapy of hyperoxia lung injury

Supraphysiological oxygen is the most conventional method of treating patients with acute respiratory failure, but prolonged exposure to hyperoxia generates large amounts of reactive oxygen species (ROS) in the lungs, leading to hyperoxia lung injury (HLI). Nevertheless, there is no safe and effective prevention strategy. Herein, multienzyme active melanin nanodots were developed as an antioxidant-immunomodulatory defense nanoplatform for the treatment of HLI. The prepared nanodots are about 4 nm in size and are mainly composed of carbon, nitrogen and oxygen elements with high stability and multi-enzymatic activity for scavenging various reactive oxygen and reactive nitrogen radicals. Cellular experiments showed that melanin nanodots increased cell viability and ameliorated hyperoxia-induced morphological changes, mitochondrial damage and apoptosis. Meanwhile, by activating the Nrf2/Keap1/HO-1 signaling pathway, the treatment of melanin nanodots significantly inhibited the overproduction of ROS, reduced malondialdehyde, and increased the endogenous antioxidant enzyme activity in BEAS-2B cells. Interestingly, the antioxidant properties of melanin nanodots indirectly promoted the phenotypic shift of macrophages, and reduced hyperoxia-induced inflammatory responses in the damaged environment. In vivo NIR-II fluorescence imaging confirms the high retention of nanodots in the lungs and low accumulation in other major organs after inhalation administration, as well as the high biosafety of the melanin nanodots as they are metabolized out of the body over time via the liver and intestines. In addition, the melanin nanodots exhibited satisfactory antioxidant protection and inhibition of inflammatory cell infiltration in the lungs of HLI mouse models. Therefore, the melanin nanodots provide a potential and effective strategy for the treatment of HLI, showing great promise for application.

An immunoregulation PLGA/Chitosan aligned nanofibers with polydopamine coupling basic fibroblast growth factor and ROS scavenging for peripheral nerve regeneration

The repair and functional recovery of long-segment peripheral nerve injuries are crucial in clinical settings. Nerve conduits are seen as promising alternatives to autologous nerve grafts, but their effectiveness is limited by the controlled delivery of bioactive factors and meeting various functional requirements during different stages of repair. This research developed multifunctional nerve conduits using electrospinning and polydopamine (PDA) coating techniques to integrate bioactive substances. Chitosan-composite PLGA electrospun nerve conduits demonstrated exceptional mechanical properties and biocompatibility. Nanofibers with specific topological structures effectively promoted oriented cell growth. The PDA coating provided ROS scavenging and immune modulation functions. The bFGF growth factor attached to the PDA coating facilitated sustained release, enhancing Schwann cell functionality and stimulating neurite outgrowth. In a rat sciatic nerve defect model with a 10 mm gap, PLGA/CS-PDA-bFGF nerve conduits showed a positive impact on nerve regeneration and functional recovery. Consequently, nerve conduits with multiple functions modified with PDA-coated bioactive molecules are poised to be excellent materials for mending peripheral nerve injuries.

A novel zinc ferrite nanoparticle protects against MSU-induced gout arthritis via Nrf2/NF-κB/NLRP3 pathway

AIMS

Gouty arthritis (GA), a prevalent and intricate form of inflammatory arthritis, affects individuals across all age groups. Existing therapeutic agents for GA are associated with substantial adverse effects. The overarching objective of this study is to identify an efficacious and biocompatible intervention strategy for GA.

MATERIALS AND METHODS

In this investigation, we developed a zinc ferrite nanoparticle (ZFN) characterized by outstanding catalytic activities in anti-inflammatory and antioxidative processes, along with negligible biotoxicity. ZFN features low-content Zn2+ doping, which effectively overcomes the issue of low biocompatibility commonly encountered in Zn-based nanoparticles. Both in vitro and in vivo experimental models were utilized to comprehensively evaluate the effects of ZFN.

KEY FINDINGS

The experimental results demonstrate that ZFN exhibits remarkable efficacy in alleviating inflammation and oxidative stress both in vitro and in vivo. It exerts its therapeutic effect on GA by modulating the NF-κB signaling pathway, suppressing the activation of the NLRP3 inflammasome, and activating the Nrf2 pathway.

SIGNIFICANCE

The protective effect of ZFN against GA holds great promise for the clinical translation of biocompatible inorganic nanoplatforms in the treatment of GA. This finding offers a potential alternative to the currently available medications, thereby providing new insights and possibilities for the management of GA.

Unexplored Mechanisms of Photoprotection: Synergistic Light Absorption and Antioxidant Activity of Melanin

Light exposure has relevant effects both on living organisms and artificial materials. In particular, ultraviolet radiation is known to kill living cells and damage human skin but also degrade important artificial materials like plastics. In nature, the main pigment responsible for photoprotection is melanin, which is able both to prevent penetration of light by absorption and scattering and to block the action of light-generated radicals thanks to its antioxidant properties. The combination of light extinction with antioxidant action is still the most diffused and effective approach to photoprotection. Nevertheless, up to now, these two mechanisms, light extinction and antioxidant activity, have been considered independent. Recent studies showed that exposing melanin to light leads to an increase in its radical content and possibly in its antioxidant activity. Do light extinction and antioxidant activity work in synergy for photoprotection in nature? In this paper, we discuss the steps still needed to answer this intriguing question.

Molecularly Imprinted Polyaniline-Coated Cu-Zeolitic Imidazolate Framework Nanoparticles: Uricase-Mimicking "Polynanozyme" Catalyzing Uric Acid Oxidation

One of the drawbacks of nanozyme catalytic functions rests in their moderate catalytic activities due to the lack of effective binding sites concentrating the reaction substrate at the nanozyme catalytic interface. Methods to concentrate the substrates at the catalytic interface are essential to improving nanozyme functions. The present study addresses this goal by designing uric acid (UA) molecular-imprinted polyaniline (PAn)-coated Cu-zeolitic imidazolate framework (Cu-ZIF) nanoparticles as superior nanozymes, "polynanozymes", catalyzing the H2O2 oxidation of UA to allantoin (peroxidase activity) or the aerobic, uricase mimicking, oxidation of UA to allantoin (oxidase activity). While bare Cu-ZIF nanoparticles reveal only peroxidase activity and the nonimprinted PAn-coated Cu-ZIF nanoparticles reveal inhibited peroxidase activity, the molecular-imprinted PAn-coated Cu-ZIF nanoparticles reveal a 6.1-fold enhanced peroxidase activity, attributed to the concentration of the UA substrate at the catalytic nanoparticle interface. Moreover, the catalytic aerobic oxidation of UA to allantoin by the imprinted PAn-coated Cu-ZIF nanoparticles is lacking in the bare particles, demonstrating the evolved catalytic functions in the molecularly imprinted polynanozymes. Mechanistic characterization of the system reveals that within the UA molecular imprinting process of the PAn coating, Cu+ reactive units are generated within the Cu-ZIF nanoparticles, and these provide reactive sites for generating O2-• as an intermediate agent guiding the oxidase activities of the nanoparticles. The study highlights the practical utility of molecular-imprinted polynanozymes in catalytic pathways lacking in the bare nanozymes, thus broadening the scope of nanozyme systems.

Ce12V6 Clusters with Multi-Enzymatic Activities for Sepsis Treatment

Artificial enzymes, especially nanozymes, have attracted wide attention due to their controlled catalytic activity, selectivity, and stability. The rising Cerium-based nanozymes exhibit unique SOD-like activity, and Vanadium-based nanozymes always hold excellent GPx-like activity. However, most inflammatory diseases involve polymerase biocatalytic processes that require multi-enzyme activities. The nanocomposite can fulfill multi-enzymatic activity simultaneously, but large nanoparticles (>10 nm) cannot be excreted rapidly, leading to biosafety challenges. Herein, atomically precise Ce12V6 clusters with a size of 2.19 nm are constructed. The Ce12V6 clusters show excellent glutathione peroxidase (GPx) -like activity with a significantly lower Michaelis-Menten constant (Km, 0.0125 mM versus 0.03 mM of natural counterpart) and good activities mimic superoxide dismutase (SOD) and peroxidase (POD). The Ce12V6 clusters exhibit the ability to scavenge the ROS including O2 ·- and H2O2 via the cascade reactions of multi-enzymatic activities. Further, the Ce12V6 clusters modulate the proinflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) and consequently rescue the multi-organ failure in the lipopolysaccharide (LPS)-induced sepsis mouse model. With excellent biocompatibility, the Ce12V6 clusters show promise in the treatment of sepsis.

New horizons for the therapeutic application of nanozymes in cancer treatment

The advent of nanozymes has revolutionized approaches to cancer diagnosis and therapy, introducing innovative strategies that address the limitations of conventional treatments. Nanozyme nanostructures with enzyme-mimicking catalytic abilities exhibit exceptional stability, biocompatibility, and customizable functions, positioning them as promising tools for cancer theranostics. By emulating natural enzyme reactions, nanozymes can selectively target and eradicate cancer cells, minimizing harm to adjacent healthy tissues. Nanozymes can also be functionalized with specific targeting ligands, allowing for the precise delivery and regulated release of therapeutic agents, improving treatment effectiveness and reducing adverse effects. However, issues such as biocompatibility, selectivity, and regulatory compliance remain critical challenges for the clinical application of nanozymes. This review provides an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments. The strategic oncological deployment of nanozymes could profoundly impact future advancements in personalized medicine, highlighting recent progress and prospective directions in enzyme-mimetic approaches for cancer treatment. This review summarizes an overview of nanozymes, highlighting their unique properties, various classifications, catalytic activities, and diverse applications in cancer treatments.

Shear force-ROS sequential responsive drug delivery system for improving cerebral thrombosis microcirculation and neurological function

The ischemic strokes seriously threaten human health with high incidence and disability rates. Cerebral embolism and impaired brain function are the two major clinical features of this disease. Therefore, rapid restoration of cerebral blood supply and synchronous improvement of impaired neurological function is the key to treating strokes. Herein, based on the microenvironment of cerebral thrombosis and pathological characteristics of damaged neurons, we constructed a shear force and reactive oxygen species (ROS) dual-responsive system (UK@Fuc/CDPC-PTPCS) for sequential targeted delivery of thrombolytic agent urokinase (UK) and neuroprotective drug cytosolic choline (CDPC). Results proved that after intravenous administration, UK@Fuc/CDPC-PTPCS can quickly locate to cerebral thrombosis site via the active recognition capability of fucoidan (Fuc) to P-selectin overexpressed on activated platelets. Subsequently, the sharply increased blood shear force separated the core-shell structure by breaking the host-guest interaction of β-cyclodextrin (β-CD), so the UK loaded in the shell was first released to rapid thrombolysis and then restored cerebral blood supply. Afterward, the stroke homing peptide (SHp) modified CDPC-PTPCS core actively recognized ischemic damaged neuronal cells. Then high intracellular ROS triggered CDPC release at specific sites to exert neuroprotective effects. This study offered a new therapeutic strategy for ischemic stroke.

Copper-Based Bio-Coordination Nanoparticle for Enhanced Pyroptosis-Cuproptosis Cancer Immunotherapy through Redox Modulation and Glycolysis Inhibition

Copper-based nanoparticles have garnered significant interest in cancer therapy due to their ability to induce oxidative stress and cuproptosis in cancer cells. However, their antitumor effectiveness is constrained by the dynamic redox balance and the metabolic shift between oxidative phosphorylation and glycolysis. Here, a polydopamine-coated copper-α-ketoglutaric acid (α-KG) coordination polymer nanoparticle (CKPP) is designed for combined pyroptosis-cuproptosis cancer immunotherapy by amplifying reactive oxygen species (ROS) production and regulating cellular metabolism. The intracellular redox imbalance is achieved through the synergistic effects of α-KG-induced mitochondrial metabolic reprogramming, photothermally enhanced superoxide dismutase-like activity of polydopamine, and glutathione depletion by copper ions. The multifaceted redox modulation results in a substantial increase in intracellular ROS levels, triggering oxidative stress and subsequent pyroptosis in cancer cells. Furthermore, α-KG shifts cellular metabolism from glycolysis to oxidative phosphorylation, thereby enhancing cuproptosis induced by copper ions. The combination of ROS dyshomeostasis and glycolysis inhibition results in a potent enhancement of pyroptosis-cuproptosis-mediated cancer therapy. In a murine model of colorectal cancer, CKPP exhibited a remarkable anticancer effect, achieving a tumor inhibition rate of 96.3% and complete tumor eradication in two out of five cases. Overall, this bio-engineered metal-organic nanocomposite demonstrates significant potential for treating cancer through combined pyroptosis-cuproptosis cancer immunotherapy.

Mesoporous Prussian blue nanoparticle neuroconduit for the biological therapy targeting oxidative stress reduction, inflammation inhibition, and nerve regeneration

The applications of nanomaterials in regenerative medicine encompass a broad spectrum. The functional nanomaterials, such as Prussian blue and its derivative nanoparticles, exhibit potent anti-inflammatory and antioxidant properties. By combining it with the corresponding scaffold carrier, the fusion of nanomaterials and biotherapy can be achieved, thereby providing a potential avenue for clinical treatment. The present study demonstrates the fabrication of a Mesoporous Prussian blue nanoparticles (MPBN) functionalized Inverse Opal Film (IOF) neuroconduit for peripheral nerve repair through reverse replication and freeze-drying techniques. The binding of MPBN to the neuroconduit can effectively decreasing reactive oxygen species and inflammatory factors in the vicinity of the residual nerve, thereby providing protective effects on the damaged nerve. Furthermore, comprehensive behavioral, electrophysiological, and pathological analyses unequivocally substantiate the efficacy of MPBN in increasing nerve structure regeneration and ameliorating denervation-induced myopathy. Moreover, MPBN enhances the antioxidant capacity of Schwann cells by activating the AMPK/SIRT1/PGC-1 pathway. The findings suggest that MPBN, a biocompatible nanoparticle, can safeguard damaged nerves by optimizing the microenvironment surrounding nerve cells and augmenting the antioxidant capacity of nerve cells, thereby facilitating nerve regeneration and repair. This also establishes a theoretical foundation for exploring the integration and clinical translation between nanomaterials and biotherapy.

A natural polyphenolic nanoparticle--knotted hydrogel scavenger for osteoarthritis therapy

Exploring highly efficient and cost-effective biomaterials for osteoarthritis (OA) treatment remains challenging, as current therapeutic strategies are difficult to eradicate the excessive reactive oxygen species (ROS) and nitric oxide (NO) at damaged sites. Tea polyphenol (TP) nanoparticles (NPs), a nature-inspired antioxidant in combination with 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a NO scavenger, could provide maximized positive therapeutic effects on OA by eradicating both ROS and NO. Notably, this combination not only improves the half-life of the TP monomer and the drug loading efficiency of carboxy-PTIO but also prevents nitrite from being harmful to tissue. Moreover, the protonation ability of carboxy-PTIO allows smart acid-responsive release in response to environmental pH, which provides conditioned treatment strategies for OA. In in vitro experiments, TP/PTIO NPs downregulated proinflammatory cytokine release via synergistic removal of ROS and NO and suppression of ROS/NF-κB and iNOS/NO/Caspase-3 signaling. For in vivo experiments, NPs were cross-linked with 4-arm-PEG-SH to form an injectable hydrogel system. The release of TP and carboxy-PTIO from the system efficiently prevents cartilage inflammation and damage via similar signaling pathways. Overall, the proposed system provides an efficient approach for OA therapy.

Mitochondrial Uncoupling Protein-2 Ameliorates Ischemic Stroke by Inhibiting Ferroptosis-Induced Brain Injury and Neuroinflammation

Ischemic stroke is a devastating disease in which mitochondrial damage or dysfunction substantially contributes to brain injury. Mitochondrial uncoupling protein-2 (UCP2) is a member of the UCP family, which regulates production of mitochondrial superoxide anion. UCP2 is reported to be neuroprotective for ischemic stroke-induced brain injury. However, the molecular mechanisms of UCP2 in ischemic stroke remain incompletely understood. In this study, we investigated whether and how UCP2 modulates neuroinflammation and regulates neuronal ferroptosis following ischemic stroke in vitro and in vivo. Wild-type (WT) and UCP2 knockout (Ucp2-/-) mice were subjected to middle cerebral artery occlusion (MCAO). BV2 cells (mouse microglial cell line) and HT-22 cells (mouse hippocampal neuronal cell line) were transfected with small interfering (si)-RNA or overexpression plasmids to knockdown or overexpress UCP2 levels. Cells were then exposed to oxygen-glucose deprivation and reoxygenation (OGD/RX) to simulate hypoxic injury in vitro. We found that UCP2 expression was markedly reduced in a time-dependent manner in both in vitro and in vivo ischemic stroke models. In addition, UCP2 was mainly expressed in neurons. UCP2 deficiency significantly enlarged infarct volumes, aggravated neurological deficit scores, and exacerbated cerebral edema in mice after MCAO. In vitro knockdown of Ucp2 and in vivo genetic depletion of Ucp2 (Ucp2-/- mice) increased neuronal ferroptosis-related indicators, including Fe2+, malondialdehyde, glutathione, and lipid peroxidation. Overexpression of UCP2 in neuronal cells resulted in reduced ferroptosis. Moreover, knockdown of UCP2 exacerbated neuroinflammation in BV2 microglia and mouse ischemic stroke models, suggesting that endogenous UCP2 inhibits neuroinflammation following ischemic stroke. Upregulation of UCP2 expression in microglia appeared to decrease the release of pro-inflammatory factors and increase the levels of anti-inflammatory factors. Further investigation showed that UCP2 deletion inhibited expression of AMPKα/NRF1 pathway-related proteins, including p-AMPKα, t-AMPKα, NRF1, and TFAM. Thus, UCP2 protects the brain from ischemia-induced ferroptosis by activating AMPKα/NRF1 signaling. Activation of UCP2 represents an attractive strategy for the prevention and treatment of ischemic stroke.

Melanin-like nanoparticles slow cyst growth in ADPKD by dual inhibition of oxidative stress and CREB

Melanin-like nanoparticles (MNPs) have recently emerged as valuable agents in antioxidant therapy due to their excellent biocompatibility and potent capacity to scavenge various reactive oxygen species (ROS). However, previous studies have mainly focused on acute ROS-related diseases, leaving a knowledge gap regarding their potential in chronic conditions. Furthermore, apart from their well-established antioxidant effects, it remains unclear whether MNPs target other intracellular molecular pathways. In this study, we synthesized ultra-small polyethylene glycol-incorporated Mn2+-chelated MNP (MMPP). We found that MMPP traversed the glomerular filtration barrier and specifically accumulated in renal tubules. Autosomal dominant polycystic kidney disease (ADPKD) is a chronic genetic disorder closely associated with increased oxidative stress and featured by the progressive enlargement of cysts originating from various segments of the renal tubules. Treatment with MMPP markedly attenuated oxidative stress levels, inhibited cyst growth, thereby improving renal function. Interestingly, we found that MMPP effectively inhibits a cyst-promoting gene program downstream of the cAMP-CREB pathway, a crucial signaling pathway implicated in ADPKD progression. Mechanistically, we observed that MMPP directly binds to the bZIP DNA-binding domain of CREB, leading to competitive inhibition of CREB's DNA binding ability and subsequent reduction in CREB target gene expression. In summary, our findings identify an intracellular target of MMPP and demonstrate its potential for treating ADPKD by simultaneously targeting oxidative stress and CREB transcriptional activity.

Nanotechnology approaches to drug delivery for the treatment of ischemic stroke

Ischemic stroke is a major global public health concern that lacks effective treatment options. A significant challenge lies in delivering therapeutic agents to the brain due to the restrictive nature of the blood-brain barrier (BBB). The BBB's selectivity hampers the delivery of therapeutically relevant quantities of agents to the brain, resulting in a lack of FDA-approved pharmacotherapies for stroke. In this article, we review therapeutic agents that have been evaluated in clinical trials or are currently undergoing clinical trials. Subsequently, we survey strategies for synthesizing and engineering nanoparticles (NPs) for drug delivery to the ischemic brain. We then provide insights into the potential clinical translation of nanomedicine, offering a perspective on its transformative role in advancing stroke treatment strategies. In summary, existing literature suggests that drug delivery represents a major barrier for clinical translation of stroke pharmacotherapies. While nanotechnology has shown significant promise in addressing this challenge, further advancements aimed at improving delivery efficiency and simplifying formulations are necessary for successful clinical translation.

Recent Trends in the Development and Application of Nano-Antioxidants for Skin-Related Disease

Skin is a vital barrier for the human body, protecting against external environmental influences and maintaining internal homeostasis. In addition, an imbalance of oxidative stress and antioxidant mechanisms can lead to skin-related diseases. Thus, for treating skin-related diseases, antioxidant therapy may be an important strategy to alleviate these symptoms. However, traditional drug therapies have limitations in treating these conditions, such as lack of lasting effect and insufficient skin permeability. Recently, nano-antioxidants, with their good permeability, sustained-release ability, multifunctionality, and other beneficial characteristics, have showed their advances in the exploration of skin-related diseases from research on safe therapies to clinical practice. Hereby, we review the latest research and advancements in nano-antioxidants for skin-related diseases. We categorize skin-related diseases into four main groups: skin inflammatory diseases, skin damage caused by ultraviolet rays, skin wound healing, and other skin-related conditions. Additionally, we summarize the prospects and potential future directions for nano-antioxidant drugs in treating skin-related diseases.

A hindered phenol containing PVC/CuO nanocomposites; study on the mechanical and thermooxidative properties

The effect of synthesized 5-((4-hydroxy-3,5-di-tert-butylphenyl)diazenyl)isophthalic acid (HBA) containing a hindered phenol derivative on the thermooxidation, hydrochloric acid release time, and mechanical strength of PVC/CuO nanocomposites was studied. Moreover, 5-((4-hydroxy-2,5-dimethylphenyl)diazenyl)isophthalic acid (HMA) was synthesized for comparison of corresponding PVC nanocomposite properties. PVC nanocomposite thin films were prepared through in situ surface modification of CuO nanoparticles with HBA and HMA, individually, in the PVC solution. The XRD and FE-SEM results clarified the desirable dispersion of CuO nanoparticles. The PVC sample with loading of 5 wt% from each HBA and CuO was found to be the most thermally stable, which was confirmed by thermogravimetric analysis in inert conditions. The thermooxidation and Congo red test results revealed that the simultaneous loading of HBA and CuO nanoparticles into the PVC matrix could increase the initial thermal degradation and the stability times. Moreover, the PVC sample containing 2.5 wt% each from HBA and CuO nanoparticles exhibited tensile strength almost 20 MPa more than that of neat PVC.

Nano revolutions in ischemic stroke: A critical analysis of current options and the potential of nanomedicines in diagnosis and therapeutics

A stroke, also known as cerebrovascular accident, is a medical emergency that occurs when the blood supply to the brain is interrupted. This disruption can happen in two main ways: through a hemorrhagic stroke, where a blood vessel in the brain bursts, or through an ischemic stroke, where a blood clot blocks an artery. Both types of stroke cause damage to brain cells, leading to a range of health complications. Globally, stroke ranks as the second leading cause of death and disability.This review provides an overview of stroke, focusing on its early detection, current treatment options, and emerging therapies. We discuss the complex mechanisms that contribute to stroke development, including the roles of cells, biomolecules, and blood vessels. Additionally, the review explores recent advances in the use of nanoparticles to enhance the efficacy of the pharmacotherapy of stroke, particularly ischemic stroke. Ongoing clinical trials in stroke management are also highlighted. Timely diagnosis and prompt intervention are critical for improving patient outcomes.We aim to increase awareness and understanding of stroke among researchers and healthcare professionals, ultimately improving patient care.

Ultra-Small Copper-Based Multienzyme-Like Nanoparticles Protect Against Hepatic Ischemia-Reperfusion Injury Through Scavenging Reactive Oxygen Species in Mice

Hepatic ischemia-reperfusion injury (IRI) is a severe complication that occurs in the process of liver transplantation, hepatectomy, and other end-stage liver disease surgery, often resulting in the failure of surgery operation and even patient death. Currently, there is no effective way to prevent hepatic IRI clinically. Here, it is reported that the ultra-small copper-based multienzyme-like nanoparticles with catalase-like (CAT-like) and superoxide dismutase-like (SOD-like) catalytic activities significantly scavenge the surge-generated endogenous reactive oxygen species (ROS) and effectively protects hepatic IRI. Density functional theory calculations confirm that the nanoparticles efficiently scavenge ROS through their synergistic effects of the ultra-small copper SOD-like activity and manganese dioxides CAT-like activity. Furthermore, the results show that the biocompatible CMP NPs significantly protected hepatocytes from IRI in vitro and in vivo. Importantly, their therapeutic effect is much stronger than that of N-acetylcysteamine acid (NAC), an FDA-approved antioxidative drug. Finally, it is demonstrated that the protective effects of CMP NPs on hepatic IRI are related to suppressing inflammation and hepatocytic apoptosis and maintaining endothelial functions through scavenging ROS in liver tissues. The study can provide insight into the development of next-generation nanomedicines for scavenging ROS.

RVG-peptide-camouflaged iron-coordinated engineered polydopamine nanoenzyme with ROS scavenging and inhibiting inflammatory response for ischemic stroke therapy

Stroke is one of the most common causes of death and disability. In addition, most neuroprotective agents fail to rescue neurons from cerebral ischemic insults due to their poor ability to penetrate the blood-brain barrier (BBB). Here, the tailored engineered nanoenzyme has been successfully synthesized by coordination-driven co-assembly of dopamine (DA) and iron ion (Fe3+), which is subsequently camouflaged by neuron-specific rabies viral glycoprotein (RVG) peptide to scavenge reactive oxygen species (ROS) and inhibit inflammatory response in damaged neuron for the efficient therapy of ischemic stroke. The resulting nanoenzyme with good biocompatibility, core-shell structure, and suitable diameter can nondestructively cross the BBB and then internalize into the damaged neuron through the camouflaging and homologous targeted strategy of neuron-specific RVG peptide. After intravenous injection into transient middle cerebral artery occlusion (tMCAO) mouse models, nanoenzyme exerted a significant neuroprotective effect, resulting in a 50 % reduction in neurological scores and an approximate 33 % decrease in cerebral infarction volume. Interestingly, such nanoenzyme can eliminate free radicals, reduce neuroinflammation, enhance BBB integrity, improve mitochondrial function, and inhibit neuronal ferroptosis. Taken together, this well-designed nanoenzyme with its excellent biocompatibility and well-understood mechanisms holds promise a robust therapy for ischemic stroke.

Genetically modified E. Coli secreting melanin (E.melanin) activates the astrocytic PSAP-GPR37L1 pathway and mitigates the pathogenesis of Parkinson's disease

The characteristic neuropathology of Parkinson's disease (PD) involves the abnormal accumulation of phosphorylated α-synuclein (αSyn), as well as a significant decrease in neuromelanin (NM) levels within dopamine neurons (DaNs). Unlike αSyn aggregates, the relationship between NM levels and PD pathogenesis is not well understood. In this study, we engineered an E. coli MG1655 strain to produce exosomes containing melanin (E.melanin), and investigated its potential neuroprotective effects on DaNs in the context of PD. By employing a combination of cell cultures, biochemical studies, single nuclear RNA sequencing (snRNA seq), and various in vivo validations, we found that administration of E.melanin effectively alleviated DaNs loss and improved motor behavior impairments observed in both pharmacological and transgenic PD mouse models. Mechanistically, snRNA seq data suggested that E.melanin activated the PSAP-GPR37L1 signaling pathway specifically within astrocytes, leading to a reduction in astrocytic engulfment of synapses. Notably, activation of the GPR37L1 receptor using Tx14(A) peptide successfully rescued motor defects as well as protected against DaNs degeneration in mice with PD. Overall, our findings provide novel insights into understanding the molecular mechanisms underlying melanin's protective effects on DaNs in PD while offering potential strategies for manipulating and treating its pathophysiological progression.

Implantation of biomimetic polydopamine nanocomposite scaffold promotes optic nerve regeneration through modulating inhibitory microenvironment

Optic nerve regeneration remains challenging worldwide due to the limited intrinsic regenerative capacity of retinal ganglion cells (RGCs) and the inhibitory microenvironment. Oxidative stress, induced by excessive reactive oxygen species (ROS) following optic nerve injury, is associated with prolonged neuroinflammation, resulting in a secondary injury of RGCs and the impairment of axon regeneration. Herein, we developed a bionic nanocomposite scaffold (GA@PDA) with immunoregulatory ability for enhanced optic nerve regeneration. The ice-templating method was employed to fabricate biopolymer-based scaffolds with a directional porous structure, mimicking the optic nerve, which effectively guided the oriented growth of neuronal cells. The incorporation of bioinspired polydopamine nanoparticles (PDA NPs) further confers excellent ROS scavenging ability, thereby modulating the phenotype transformation of microglia/macrophages from pro-inflammatory M1 to anti-inflammatory M2. In a rat optic nerve crush model, the implantation of GA@PDA scaffold enhanced survival of RGCs and promoted axonal regeneration. Our study offers novel insights and holds promising potential for the advancement of engineered biomaterials in facilitating optic nerve regeneration.

Polydopamine Nanoformulations Induced ICD and M1 Phenotype Macrophage Polarization for Enhanced TNBC Synergistic Photothermal Immunotherapy

Photothermal therapy (PTT) is a promising technology that can achieve the thermal ablation of tumors and induce immunogenic cell death (ICD). However, relying solely on the antitumor immune responses caused by PTT-induced ICD is insufficient to suppress tumor metastasis and recurrence effectively. Fortunately, multifunctional nanoformulation-based synergistic photothermal immunotherapy can eliminate primary and metastatic tumors and inhibit tumor recurrence for a long time. Herein, we select polydopamine (PDA) nanoparticles to serve as the carrier for our nanomedicine as well as a potent photothermal agent and modulator of macrophage polarization. PDA nanoparticles are loaded with the insoluble immune adjuvant Imiquimod (R837) to construct PDA(R837) nanoformulations. These straightforward yet highly effective nanoformulations demonstrate excellent performance, allowing for successful triple-negative breast cancer (TNBC) treatment through synergistic photothermal immunotherapy. Moreover, experimental results showed that PDA(R837) implementation of PTT is effective in the thermal ablation of primary tumors while causing ICD and releasing R837, further promoting dendritic cell (DC) maturation and activating the systemic antitumor immune response. Furthermore, PDA(R837) nanoformulations inhibit tumor metastasis and recurrence and achieve M1 phenotype macrophage polarization, achieving long-term and excellent antitumor efficacy. Therefore, the structurally simple PDA(R837) nanoformulations provide cancer treatment and have excellent clinical translational application prospects.

2D MXene Biomaterials for Catalytic Medical Applications

In recent years, two-dimensional transition metal carbides, nitrides, and carbonitrides, termed as MXenes, have been widely applied in energy storage, photocatalysis and biomedicine owing to their unique physicochemical properties of large specific surface area, high electrical conductivity, excellent optical performance, good stability, etc. Moreover, due to their strong light absorption capacity in the first and second near-infrared bio-window, and their ability of being simply functionalized with multiple organic/inorganic materials, MXene biomaterials have shown great potential in the field of catalytic therapy. This review will summarize the common catalytic mechanism of MXene biomaterials and their latest applications in catalytic medicine such as tumor therapy, antibacterial and anti-inflammatory, and present the current challenges and opportunities in clinical translation for future development to promote the advancement of MXene biomaterials in the field of catalytic medicine.

Tunicate cellulose nanocrystals strengthened injectable stretchable hydrogel as multi-responsive enhanced antibacterial wound dressing for promoting diabetic wound healing

The intricate microenvironment of diabetic wounds characterized by hyperglycemia, intense oxidative stress, persistent bacterial infection and complex pH fluctuations hinders the healing process. Herein, an injectable multifunctional hydrogel (QPTx) was developed, which exhibited excellent mechanical performance and triple responsiveness to pH, temperature, and glucose due to dynamic covalent cross-linking involving dynamic Schiff base bonds and phenylboronate esters with phenylboronic-modified quaternized chitosan (QCS-PBA), polydopamine coated tunicate cellulose crystals (PDAn@TCNCs) and polyvinyl alcohol (PVA). Furthermore, the hydrogels can incorporate insulin (INS) drugs to adapt to the complex and variable wound environment in diabetic patients for on-demand drug release that promote diabetic wound healing. Based on various excellent properties of the colloidal materials, the hydrogels were evaluated for self-healing, rheological and mechanical properties, in vitro insulin response to pH/temperature/glucose release, antibacterial, antioxidant, tissue adhesion, coagulation, hemostasis in vivo and in vitro, and biocompatibility and biodegradability. By introducing PDAn@TCNCs particles, the hydrogel has photothermal antibacterial activity, enhanced adhesion and oxidation resistance. We further demonstrated that these hydrogel dressings significantly improved the healing process compared to commercial dressings (Tegaderm™) in full-layer skin defect models. All indicated that the glucose-responsive QPTx hydrogel platform has great potential for treating diabetic wounds.

Colorimetric sensor array for identifying antioxidants based on pyrolysis-free synthesis of Fe-N/C single-atom nanozymes

Iron-anchored nitrogen/doped carbon single-atom nanozymes (Fe-N/C), which possess homogeneous active sites and adjustable catalytic environment, represent an exemplary model for investigating the structure-function relationship and catalytic activity. However, the development of pyrolysis-free synthesis technique for Fe-N/C with adjustable enzyme-mimicking activity still presents a significant challenge. Herein, Fe-N/C anchored three carrier morphologies were created via a pyrolysis-free approach by covalent organic polymers. The peroxidase-like activity of these Fe-N/C nanozymes was regulated via the pores of the anchored carrier, resulting in varying electron transfer efficiency due to disparities in contact efficacy between substrates and catalytic sites within diverse microenvironments. Additionally, a colorimetric sensor array for identifying antioxidants was developed: (1) the Fe-N/C catalytically oxidized two substrates TMB and ABTS, respectively; (2) the development of a colorimetric sensor array utilizing oxTMB and oxABTS as sensing channels enabled accurate discrimination of antioxidants such as ascorbic acid (AsA), glutathione (GSH), cysteine (Cys), gallic acid (GA), and caffeic acid (CA). Subsequently, the sensor array underwent rigorous testing to validate its performance, including assessment of antioxidant mixtures and individual antioxidants at varying concentrations, as well as target antioxidants and interfering substances. In general, the present study offered valuable insights into the active origin and rational design of nanozyme materials, and highlighting their potential applications in food analysis.

Advances in nanoparticle-based therapeutics for ischemic stroke: Enhancing drug delivery and efficacy

Ischemic stroke, characterized by vascular occlusion, has recently emerged as one of the primary causes of mortality and disability worldwide. Conventional treatment modalities, such as thrombolytic and neuroprotective therapies, face numerous challenges, including limited bioavailability, significant neurotoxicity, suboptimal targeting, short half-life, and poor blood-brain barrier (BBB) penetration. Nanoparticle-based drug delivery systems present distinct advantages, such as small size, enhanced lipophilicity, and modifiability, which can potentially address these limitations. Utilizing nanoparticles for drug delivery in ischemic stroke therapy offers improved drug bioavailability, reduced neurotoxicity, enhanced targeted delivery, prolonged drug half-life, and better dissolution kinetics. This review aims to provide a comprehensive overview of current strategies in preclinical studies for managing or preventing ischemic stroke from a nanomaterial perspective, highlighting the advantages and limitations of each approach.

Fabrication of polydopamine-modified cellulose hydrogel for controlled release of α-mangostin

Hydrogels are notable for their outstanding absorbent qualities, satisfactory compatibility with biological systems, ability to degrade, and inherent safety, all of which contribute to their high demand in the field of biomedicine. This study focuses on the fabrication of hydrogels using environmentally friendly cellulosic material. Cellulose hydrogel beads were prepared by physical cross-linking in a NaOH/urea medium. Furthermore, nano polydopamine was integrated into the hydrogel matrix as functional polymers and α-mangostin was employed as an active pharmaceutical ingredient. The physicochemical properties were comprehensively analyzed using Fourier-transform infrared spectrometer, 13C cross-polarization/magic angle spinning nuclear magnetic resonance, thermogravimetric analysis, and scanning electron microscope. The drug delivery properties, including water content, swelling ratio, and drug release profiles, were evaluated. In vitro cytotoxicity against MC3T3-E1 cells was assessed using sulforhodamine B staining. All test hydrogels exhibited inhibitory activity against the growth of MC3T3-E1 cells. These results indicated the potential use of these hydrogels as a drug delivery carrier for α-mangostin in the treatment of ankylosing spondylitis.

Phenolic-enabled nanotechnology: a new strategy for central nervous system disease therapy

Polyphenolic compounds have received tremendous attention in biomedicine because of their good biocompatibility and unique physicochemical properties. In recent years, phenolic-enabled nanotechnology (PEN) has become a hotspot of research in the medical field, and many promising studies have been reported, especially in the application of central nervous system (CNS) diseases. Polyphenolic compounds have superior anti-inflammatory and antioxidant properties, and can easily cross the blood‒brain barrier, as well as protect the nervous system from metabolic damage and promote learning and cognitive functions. However, although great advances have been made in this field, a comprehensive review regarding PEN-based nanomaterials for CNS therapy is lacking. A systematic summary of the basic mechanisms and synthetic strategies of PEN-based nanomaterials is beneficial for meeting the demand for the further development of novel treatments for CNS diseases. This review systematically introduces the fundamental physicochemical properties of PEN-based nanomaterials and their applications in the treatment of CNS diseases. We first describe the different ways in which polyphenols interact with other substances to form high-quality products with controlled sizes, shapes, compositions, and surface chemistry and functions. The application of PEN-based nanomaterials in the treatment of CNS diseases is then described, which provides a reference for subsequent research on the treatment of CNS diseases.

Application of Nanozymes and its Progress in the Treatment of Ischemic Stroke

Nanozymes are a new kind of material which has been applied since the beginning of this century, and its birth has promoted the development of chemistry, materials science, and biology. Nanozymes can be used as a substitute for natural enzyme and has a wide range of applications; therefore, it has attracted extensive attention from all sectors of the community, and the number of studies has constantly increasing. In this paper, we introduced the outstanding achievements in the field of nanozymes in recent years from the main function, the construction of nanozyme-based biosensors, and the treatment of ischemic stroke, and we also illustrated the internal mechanism and the catalytic principle. In the end, the obstacles and challenges in the future development of nanozymes were proposed.

The Exploration of Nanozymes for Biosensing of Pathological States Tailored to Clinical Theranostics

The nanozymes (NZs) are the artificial catalyst deployed for biosensing with their uniqueness (high robustness, surface tenability, inexpensive, and stability) for obtaining a better response/miniaturization of the varied sensors than their traditional ancestors. Nowadays, nanomaterials with their broadened scale such as metal-organic frameworks (MOFs), and metals/metal oxides are widely engaged in generating NZ-based biosensors (BS). Diverse strategies like fluorescent, colorimetric, surface-enhanced Raman scattering (SERS), and electrochemical sensing principles were implemented for signal transduction of NZs. Despite broad advantages, numerous encounters (like specificity, feasibility, stability, and issues in scale-up) are affecting the potentialities of NZs-based BS, and thus need prior attention for a promising exploration for a revolutionary outcome in advanced theranostics. This review includes different types of NZs, and the progress of numerous NZs tailored bio-sensing techniques in detecting abundant bio analytes for theranostic purposes. Further, the discussion highlighted some recent challenges along with their progressive way of possibly overcoming followed by commercial outbreaks.

Advanced nanomedicines for the treatment of age-related macular degeneration

The critical and unmet medical need for novel therapeutic advancements in the treatment of age-related macular degeneration (AMD) cannot be overstated, particularly given the aging global population and the increasing prevalence of this condition. Current AMD therapy involves intravitreal treatments that require monthly or bimonthly injections to maintain optimal efficacy. This underscores the necessity for improved approaches, prompting recent research into developing advanced drug delivery systems to prolong the intervals between treatments. Nanoparticle-based therapeutic approaches have enabled the controlled release of drugs, targeted delivery of therapeutic materials, and development of smart solutions for the harsh microenvironment of diseased tissues, offering a new perspective on ocular disease treatment. This review emphasizes the latest pre-clinical treatment options in ocular drug delivery to the retina and explores the advantages of nanoparticle-based therapeutic approaches, with a focus on AMD, the leading cause of irreversible blindness in the elderly.

Ototoxicity-Alleviating and Cytoprotective Allomelanin Nanomedicine for Efficient Sensorineural Hearing Loss Treatment

Sensorineural hearing loss (SNHL) represents a significant clinical challenge, predominantly attributed to oxidative stress-related mechanisms. In this work, we report an innovative antioxidant strategy for mitigating SNHL, utilizing synthetically engineered allomelanin nanoparticles (AMNPs). Empirical evidence elucidates AMNPs' profound capability in free radical neutralization, substantiated by a significant decrement in reactive oxygen species (ROS) levels within HEI-OC1 auditory cells exposure to cisplatin or hydrogen peroxide (H2O2). Comparative analyses reveal that AMNPs afford protection against cisplatin-induced and noise-induced auditory impairments, mirroring the effect of dexamethasone (DEX), a standard pharmacological treatment for acute SNHL. AMNPs exhibit notable cytoprotective properties for auditory hair cells (HCs), effectively preventing ototoxicity from cisplatin or H2O2 exposure, as confirmed by both in vitro assays and cultured organ of Corti studies. Further in vivo research corroborates AMNPs' ability to reverse auditory brainstem response (ABR) threshold shifts resulting from acoustic injury, concurrently reducing HCs loss, ribbon synapse depletion, and spiral ganglion neuron degeneration. The therapeutic benefits of AMNPs are attributed to mitigating oxidative stress and inflammation within the cochlea, with transcriptome analysis indicating downregulated gene expression related to these processes post-AMNPs treatment. The pronounced antioxidative and anti-inflammatory effects of AMNPs position them as a promising alternative to DEX for SNHL treatment.

Protective properties of melanin from lichen Lobaria pulmonaria (L.) HOFFM. In models of oxidative stress in skeletal muscle

Melanin is a dark pigment from the group of phenolic or indole polymers with inherent biocompatibility and antioxidant capacity. In extremophilic lichen Lobaria pulmonaria, melanin is responsible for protective properties against hostile environments. Herein, the ability of melanin extracted from L. pulmonaria to counteract oxidative stress and related damages was studied in the mouse diaphragm, the main respiratory muscle. Initial in vitro experiments demonstrated ultraviolet (UV)-absorbing, antioxidant and metal chelating activities of melanin. This melanin can form nanoparticles and stabile colloidal system at concentration of 5 μg/ml. Pretreatment of the muscle with melanin (5 μg/ml) markedly reduced UV-induced increase in intracellular and extracellular reactive oxygen species (ROS) as well as antimycin A-mediated enhancement in mitochondrial ROS production accompanied by lipid peroxidation and membrane asymmetry loss. In addition, melanin attenuated suppression of neuromuscular transmission and alterations of contractile responses provoked by hydrogen peroxide. Thus, this study shed the light on the perspectives of the application of a lichen melanin as a protective component for treatment of skeletal muscle disorders, which are accompanied with an increased ROS production.

Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

A Non-Metallic Nanozyme Ameliorates Pulmonary Hypertension Through Inhibiting ROS/TGF-β1 Signaling

Pulmonary hypertension (PH) is a life-threatening cardiovascular disease with a lack of effective treatment options. Nanozymes, though promising for PH therapy, pose safety risks due to their metallic nature. Here, a non-metallic nanozyme is reported for the treatment of monocrotaline (MCT)-induced PH with a therapeutic mechanism involving the ROS/TGF-β1 signaling. The synthesized melanin-polyvinylpyrrolidone-polyethylene glycol (MPP) nanoparticles showcase ultra-small size, excellent water solubility, high biocompatibility, and remarkable antioxidant capacity. The MPP nanoparticles are capable of effectively eliminating ROS in isolated pulmonary artery smooth muscle cells (PASMCs) from PH rats, and significantly reduce PASMC proliferation and migration. In vivo results from a PH model demonstrate that MPP nanoparticles significantly increase pulmonary artery acceleration time, decrease wall thickening and PCNA expression in lung tissues, as evidenced by echocardiograpy, histology and immunoblot analysis. Additionally, MPP nanoparticles treatment improve running capacity, decrease Fulton index, and attenuate right ventricular fibrosis in MCT-PH rats by using treadmill test, picrosirius red, and trichrome Masson staining. Further transcriptomic and biochemical analyses reveal that inhibiting ROS-driven activation of TGF-β1 in the PA is the mechanism by which MPP nanoparticles exert their therapeutic effect. This study provides a novel approach for treating PH with non-metallic nanozymes based on a well-understood mechanism.

Reprogramming the myocardial infarction microenvironment with melanin-based composite nanomedicines in mice

Myocardial infarction (MI) has a 5-year mortality rate of more than 50% due to the lack of effective treatments. Interactions between cardiomyocytes and the MI microenvironment (MIM) can determine the progression and fate of infarcted myocardial tissue. Here, a specially designed Melanin-based composite nanomedicines (MCN) is developed to effectively treat MI by reprogramming the MIM. MCN is a nanocomposite composed of polydopamine (P), Prussian blue (PB) and cerium oxide (CexOy) with a Mayuan-like structure, which reprogramming the MIM by the efficient conversion of detrimental substances (H+, reactive oxygen species, and hypoxia) into beneficial status (O2 and H2O). In coronary artery ligation and ischemia reperfusion models of male mice, intravenously injecting MCN specifically targets the damaged area, resulting in restoration of cardiac function. With its promising therapeutic effects, MCN constitutes a new agent for MI treatment and demonstrates potential for clinical application.

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.

Physiological Roles of Eumelanin- and Melanogenesis-Associated Diseases: A Look at the Potentialities of Engineered and Microbial Eumelanin in Clinical Practice

This paper aims to highlight the physiological actions exerted by eumelanin present in several organs/tissues of the human body and to rationalise the often conflicting functional roles played by this biopolymer on the basis of its peculiar properties. Besides pigmentary disorders, a growing number of organ injuries and degenerative pathologies are presently ascribed to the modification of physiological eumelanin levels in terms of alterations in its chemical/structural features, and of a partial loss or uneven distribution of the pigment. The present review analyses the more recent research dedicated to the physiological and pathological actions of eumelanin and provides an insight into some melanogenesis-associated diseases of the skin, eye, ear, and brain, including the most significant neurodegenerative disorders. Also described are the potentialities of therapies based on the localised supply of exogeneous EU and the opportunities that EU produced via synthetic biology offers in order to redesign therapeutical and diagnostic applications.