Ultrasmall Antioxidant Cerium Oxide Nanoparticles for Regulation of Acute Inflammation

Mg-gallate metal-organic framework-based sprayable hydrogel for continuously regulating oxidative stress microenvironment and promoting neurovascular network reconstruction in diabetic wounds

Chronic diabetic wounds are the most common complication for diabetic patients. Due to high oxidative stress levels affecting the entire healing process, treating diabetic wounds remains a challenge. Here, we present a strategy for continuously regulating oxidative stress microenvironment by the catalyst-like magnesium-gallate metal-organic framework (Mg-GA MOF) and developing sprayable hydrogel dressing with sodium alginate/chitosan quaternary ammonium salts to treat diabetic wounds. Chitosan quaternary ammonium salts with antibacterial properties can prevent bacterial infection. The continuous release of gallic acid (GA) effectively eliminates reactive oxygen species (ROS), reduces oxidative stress, and accelerates the polarization of M1-type macrophages to M2-type, shortening the transition between inflammation and proliferative phase and maintaining redox balance. Besides, magnesium ions adjuvant therapy promotes vascular regeneration and neuronal formation by activating the expression of vascular-associated genes. Sprayable hydrogel dressings with antibacterial, antioxidant, and inflammatory regulation rapidly repair diabetic wounds by promoting neurovascular network reconstruction and accelerating re-epithelialization and collagen deposition. This study confirms the feasibility of catalyst-like MOF-contained sprayable hydrogel to regulate the microenvironment continuously and provides guidance for developing the next generation of non-drug diabetes dressings.

Exploring the stable structures of cerium oxide nanoclusters using high-dimensional neural network potential

Cerium clusters have been extensively applied in industry owing to their extraordinary properties for oxygen storage and redox catalytic activities. However, their atomically precise structures have not been studied because of the lack of a reliable method to efficiently sample their complex structures. Herein, we combined a neural network algorithm with density functional theory calculations to establish a high-dimensional potential to search for the global minimums of cerium oxide clusters. Using Ce14O28 as well as its reduced state Ce14O27 and oxidized state Ce14O29 with ultra-small dimensions of ∼1.0 nm as examples, we found that these three clusters adopt pyramid-like structures with the lowest energies, which was obtained by exploring 100 000 configurations in large feasible spaces. Further the neural network potential-enhanced molecular dynamics calculations indicated that these cluster structures are stable at high temperature. The electronic structure analysis suggested that these clusters are highly active and easily lose oxygen. This work demonstrated that neural network potentials can be useful for exploring the stable structures of metal oxide nanoclusters in practical applications.

Enhanced ·OH-Scavenging Activity of Cu-CeOx Nanozyme via Resurrecting Macrophage Nrf2 Transcriptional Activity Facilitates Diabetic Wound Healing

Diabetic wounds are a prevalent and devastating complication of diabetes, which may impede their healing and regeneration. In diabetic wounds, excess reactive oxygen species (ROS) activate the nuclear factor kappa-B pathway, leading to transcriptional silencing of nuclear factor erythroid 2-related factor 2 (Nrf2), resulting in a vicious cycle of oxidative stress and inflammation. Conventional nanozymes have limitations in preventing the continuous production of ROS, including the most oxidizing reactive hydroxyl radical (·OH), although they can remove pre-existing ROS. Herein, a novel antioxidant nanoplatform addresses this challenge by incorporating JSH-23 into the mesoporous of cupric-doped cerium oxide nanozymes. Additionally, for rapid wound adaptability and durable tissue adhesion, a nanozyme hydrogel spray consisting of oxidized sodium alginate and methacrylate gelatin is constructed, named OG@CCJs. This platform resurrects Nrf2 transcriptional activity of macrophages in vitro, curbing the production of ROS at its source, particularly ·OH, while enabling the nanozymes to scavenge previously generated ROS. OG@CCJs significantly alleviate oxidative stress in diabetic wounds in vivo, promoting wound healing. Overall, the proposed nanozyme-hydrogel spray with enhanced ·OH-scavenging activity uses a "two-track" antioxidant strategy to rebuild the antioxidant defense barrier of macrophages. This pioneering approach highlights the tremendous potential of OG@CCJs for facilitating diabetic wound healing.

Bioinspired and biomimetic strategies for inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory bowel disease with high morbidity and an increased risk of cancer or death, resulting in a heavy societal medical burden. While current treatment modalities have been successful in achieving long-term remission and reducing the risk of complications, IBD remains incurable. Nanomedicine has the potential to address the high toxic side effects and low efficacy in IBD treatment. However, synthesized nanomedicines typically exhibit some degree of immune rejection, off-target effects, and a poor ability to cross biological barriers, limiting the development of clinical applications. The emergence of bionic materials and bionic technologies has reshaped the landscape in novel pharmaceutical fields. Biomimetic drug-delivery systems can effectively improve biocompatibility and reduce immunogenicity. Some bioinspired strategies can mimic specific components, targets or immune mechanisms in pathological processes to produce targeting effects for precise disease control. This article highlights recent research on bioinspired and biomimetic strategies for the treatment of IBD and discusses the challenges and future directions in the field to advance the treatment of IBD.

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.

One-pot hydrothermal synthesis of fluorophore-modified cerium oxide nanoparticles

Cerium oxide nanoparticles (CeO2 NPs), which have powerful antioxidant properties, are promising nanomaterials for the treatment of diseases associated with oxidative stress. The well-developed surface of CeO2 NPs makes them promising for use as a multifunctional system for various biomedical applications. This work demonstrates a simple approach that allows the direct formation of a molecular fluorophore on the surface of CeO2 NPs using a simple one-pot hydrothermal synthesis. Thus, we were able to synthesize CeO2 NPs of ultra-small size ∼2 nm with a narrow distribution, highly stable fluorescence, and a quantum yield of ∼62%. UV-visible transmission studies revealed that the resulting CeO2 NPs exhibited fast autogenerative catalytic reduction. In vitro results showed high biocompatibility of CeO2 NPs; their internalization occurs mainly in the region of cell nuclei. Thus, the resulting NPs have the necessary parameters and can be successfully used in biovisualization and therapy.

Ceria-Based Therapeutic Antioxidants for Biomedical Applications

The growing interest in nanomedicine over the last 20 years has carved out a research field called "nanocatalytic therapy," where catalytic reactions mediated by nanomaterials are employed to intervene in disease-critical biomolecular processes. Among many kinds of catalytic/enzyme-mimetic nanomaterials investigated thus far, ceria nanoparticles stand out from others owing to their unique scavenging properties against biologically noxious free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), by exerting enzyme mimicry and nonenzymatic activities. Much effort has been made to utilize ceria nanoparticles as self-regenerating antioxidative and anti-inflammatory agents for various kinds of diseases, given the detrimental effects of ROS and RNS therein that need alleviation. In this context, this review is intended to provide an overview as to what makes ceria nanoparticles merit attention in disease therapy. The introductory part describes the characteristics of ceria nanoparticles as an oxygen-deficient metal oxide. The pathophysiological roles of ROS and RNS are then presented, as well as their scavenging mechanisms by ceria nanoparticles. Representative examples of recent ceria-nanoparticle-based therapeutics are summarized by categorization into organ and disease types, followed by the discussion on the remaining challenges and future research directions.

Brazilin-Ce nanoparticles attenuate inflammation by de/anti-phosphorylation of IKKβ

Inflammation is associated with a series of diseases like cancer, cardiovascular disease and infection, and phosphorylation/dephosphorylation modification of proteins are important in inflammation regulation. Here we designed and synthesized a novel Brazilin-Ce nanoparticle (BX-Ce NPs) using Brazilin, which has been used for anti-inflammation in cardiovascular diseases but with narrow therapeutic window, and Cerium (IV), a lanthanide which has the general activity in catalyzing the hydrolysis of phosphoester bonds, to conferring de/anti-phosphorylation of IKKβ. We found that BX-Ce NPs specifically bound to Asn225 and Lys428 of IKKβ and inhibited its phosphorylation at Ser181, contributing to appreciably anti-inflammatory effect in cellulo (IC50 = 2.5 μM). In vivo mouse models of myocardial infarction and sepsis also showed that the BX-Ce NPs significantly ameliorated myocardial injury and improved survival in mice with experimental sepsis through downregulating phosphorylation of IKKβ. These findings provided insights for developing metal nanoparticles for guided ion interfere therapy, particularly synergistically target de/anti-phosphorylation as promising therapeutic agents for inflammation and related diseases.

Microenvironment Remodeling Self-Healing Hydrogel for Promoting Flap Survival

Random flap grafting is a routine procedure used in plastic and reconstructive surgery to repair and reconstruct large tissue defects. Flap necrosis is primarily caused by ischemia-reperfusion injury and inadequate blood supply to the distal flap. Ischemia-reperfusion injury leads to the production of excessive reactive oxygen species, creating a pathological microenvironment that impairs cellular function and angiogenesis. In this study, we developed a microenvironment remodeling self-healing hydrogel [laminarin-chitosan-based hydrogel-loaded extracellular vesicles and ceria nanozymes (LCH@EVs&CNZs)] to improve the flap microenvironment and synergistically promote flap regeneration and survival. The natural self-healing hydrogel (LCH) was created by the oxidation laminarin and carboxymethylated chitosan via a Schiff base reaction. We loaded this hydrogel with CNZs and EVs. CNZs are a class of nanomaterials with enzymatic activity known for their strong scavenging capacity for reactive oxygen species, thus alleviating oxidative stress. EVs are cell-secreted vesicular structures containing thousands of bioactive substances that can promote cell proliferation, migration, differentiation, and angiogenesis. The constructed LCH@EVs&CNZs demonstrated a robust capacity for scavenging excess reactive oxygen species, thereby conferring cellular protection in oxidative stress environments. Moreover, these constructs notably enhance cell migration and angiogenesis. Our results demonstrate that LCH@EVs&CNZs effectively remodel the pathological skin flap microenvironment and marked improve flap survival. This approach introduces a new therapeutic strategy combining microenvironmental remodeling with EV therapy, which holds promise for promoting flap survival.

Ratiometric fluorescence sensor based on europium-organic frameworks for selective and quantitative detection of cerium ions

BACKGROUND

Due to the unavoidable use of cerium in daily life, the accumulation of cerium in the environment increases health risks for humans. Therefore, it is crucial to develop a chemical sensing technology for the rapid, sensitive, and selective detection of cerium ions.

RESULTS

In this research work, a novel two-dimensional chain structure of a europium-based metal organic framework (Eu-MOF) [Eu2(tcpa)(Htcpa)2] was synthesized by using 3,4,5,6-tetrachloro-1,2-benzenedicarboxylic acid (H2TCPA) as the ligand and europium nitrate as the metal source. The results of powder X-ray diffraction and thermogravimetric analysis show that the synthesized Eu-MOF has excellent chemical and thermal stability. When the Eu-MOF suspension was excited by ultraviolet light at 292 nm, four fluorescence emissions were observed at 420, 595, 620 and 705 nm. It was particularly interesting that when cerium ions (Ce3+/Ce4+) were added to the Eu-MOF suspension, the fluorescence intensity at 420 nm was enhanced, while the fluorescence at 620 nm was quenched. On this basis, a ratiometric fluorescent sensor for detecting cerium ions was constructed, which has a good linear relationship in the range of 0.05-15 μM and a detection limit of 16 nM. The plausible mechanism of the change in the fluorescence characteristics of Eu-MOF caused by cerium ions was discussed in detail. Through the study of fluorescence lifetime and ultraviolet absorption, it was proven that the mechanism of Ce3+-quenching Eu-MOF fluorescence is the inner filter effect. Photoinduced electron transfer and internal filtering effects lead to fluorescence quenching at 620 nm, while redox reactions lead to fluorescence enhancement of the ligand at 420 nm.

SIGNIFICANCE

The proposed ratiometric fluorescence sensor was successfully employed for the detection of cerium ions in real water samples, confirming that it can be used as an alternative method for the detection of Ce3+ and Ce4+ in environmental samples.

Ultrasmall cerium oxide nanoparticles as highly sensitive X-ray contrast agents and their antioxidant effect

Owing to their theranostic properties, cerium oxide (CeO2) nanoparticles have attracted considerable attention for their key applications in nanomedicine. In this study, ultrasmall CeO2 nanoparticles (particle diameter = 1-3 nm) as X-ray contrast agents with an antioxidant effect were investigated for the first time. The nanoparticles were coated with hydrophilic and biocompatible poly(acrylic acid) (PAA) and poly(acrylic acid-co-maleic acid) (PAAMA) to ensure satisfactory colloidal stability in aqueous media and low cellular toxicity. The synthesized nanoparticles were characterized using high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, cell viability assay, photoluminescence spectroscopy, and X-ray computed tomography (CT). Their potential as X-ray contrast agents was demonstrated by measuring phantom images and in vivo CT images in mice injected intravenously and intraperitoneally. The X-ray attenuation of these nanoparticles was greater than that of the commercial X-ray contrast agent Ultravist and those of larger CeO2 nanoparticles reported previously. In addition, they exhibited an antioxidant effect for the removal of hydrogen peroxide. The results confirmed that the PAA- and PAAMA-coated ultrasmall CeO2 nanoparticles demonstrate potential as highly sensitive radioprotective or theranostic X-ray contrast agents.

Application of nanotechnology in the treatment of glomerulonephritis: current status and future perspectives

Glomerulonephritis (GN) is the most common cause of end-stage renal failure worldwide; in most cases, it cannot be cured and can only delay the progression of the disease. At present, the main treatment methods include symptomatic therapy, immunosuppressive therapy, and renal replacement therapy. However, effective treatment of GN is hindered by issues such as steroid resistance, serious side effects, low bioavailability, and lack of precise targeting. With the widespread application of nanoparticles in medical treatment, novel methods have emerged for the treatment of kidney diseases. Targeted transportation of drugs, nucleic acids, and other substances to kidney tissues and even kidney cells through nanodrug delivery systems can reduce the systemic effects and adverse reactions of drugs and improve treatment effectiveness. The high specificity of nanoparticles enables them to bind to ion channels and block or enhance channel gating, thus improving inflammation. This review briefly introduces the characteristics of GN, describes the treatment status of GN, systematically summarizes the research achievements of nanoparticles in the treatment of primary GN, diabetic nephropathy and lupus nephritis, analyzes recent therapeutic developments, and outlines promising research directions, such as gas signaling molecule nanodrug delivery systems and ultrasmall nanoparticles. The current application of nanoparticles in GN is summarized to provide a reference for better treatment of GN in the future.

Green Extracts with Metal-based Nanoparticles for Treating Inflammatory Diseases: A Review

Globally, high death rates and poor quality of life are caused mainly by inflammatory diseases. Corticosteroids, which may have systemic side effects and would enhance the risk of infection, are the common forms of therapy. The field of nanomedicine has created composite nanoparticles that carry a pharmacological carrier and target ligands for distribution to sites of inflammation with less systemic toxicity. However, their relatively large size often causes systemic clearance. An interesting approach is metal-based nanoparticles that naturally reduce inflammation. They are made not only to be small enough to pass through biological barriers but also to allow label-free monitoring of their interactions with cells. The following literature review discusses the mechanistic analysis of the anti-inflammatory properties of several metal-based nanoparticles, including gold, silver, titanium dioxide, selenium, and zinc oxide. Current research focuses on the mechanisms by which nanoparticles infiltrate cells and the anti-inflammatory techniques using herbal extracts-based nanoparticles. Additionally, it provides a brief overview of the literature on many environmentally friendly sources employed in nanoparticle production and the mechanisms of action of various nanoparticles.

Catalytically proficient ceria nanodots supported on redox-active mesoporous hosts for treatment of inflammatory bowel disease via efficient ROS scavenging

Ceria nanozyme-based ROS scavengers have shown great potential in the treatment of inflammatory bowel disease (IBD) through microenvironment regulation. However, the currently developed nanotherapeutics suffer from difficulties in concomitantly achieving small sizes and stable interparticle dispersion which is pivotal to sufficient oxygen vacancies facilitating electron transfer and oxygen storage in the dynamic cycling of Ce3+/Ce4+ redox pairs. Herein, a hybrid nanosystem consisting of ceria nanodots supported on redox-active mesoporous hosts was developed to address the challenge of ROS scavenging, in particular the efficient downregulation of the readily renewable, highly concentrated H2O2 species. Specifically, Ce4+ ions oxidized from Ce3+ in weakly basic solution were captured and reduced in time by the abundant catechols on the mesoporous polydopamine nanoparticles. This led to strong restriction of ceria growth (∼2.8 nm) in the ion precipitation process and efficient maintenance of the Ce3+/Ce4+ ratio at a high value of 1.59 which is 4.8 fold higher than that of homogeneously nucleated ceria nanoparticles. Through this design, the nanohybrid showed an attractive catalytic performance in scavenging multiple ROS species, particularly the fast and recyclable conversion of H2O2. Thereby, significant suppression of the inflammatory cytokine/chemokine secretion was achieved by inhibiting the activation of NF-κB signaling pathways (5.1 fold higher as compared to those of pristine ceria nanoparticles), upregulating the Nrf2 signaling pathway, and reducing the proportion of M1 macrophages at IBD sites. Therapeutic efficiency was also demonstrated by the effective repair of the intestinal mucosal barrier by recovering the tight junction integrity in vivo. This study sheds light on the employment of redox-active hosts to support ceria catalysts for advancing anti-inflammation applications by boosting ROS scavenging performance.

The innovative design of a delivery and real-time tracer system for anti-encephalitis drugs that can penetrate the blood-brain barrier

As a "wall" between blood flow and brain cells, the blood-brain barrier (BBB) makes it really difficult for drugs to cross this barrier and work. This is particularly the case for pharmaceuticals of acute encephalitis therapies, largely excluded from the brain following systemic administration. Herein we report an advanced drug delivery system that can cross the BBB and target acute inflammation based on the controlled release of macrophage-camouflaged glow nanoparticles via a Trojan horse strategy. Benefiting from afterglow imaging that eliminates background interference and RAW 264.7 cells (RAW) with special immune homing and long-term tracking capabilities, polydopamine (PDA)-modified afterglow nanoparticles (ANPs) as near-infrared photo-responsive drug carriers in a controlled delivery system camouflaged by macrophages can penetrate the BBB by crossing the intercellular space and trigger the anti-inflammatory drug by photothermal conversion in the brain parenchyma dexamethasone (Dex) release, exhibiting good acute inflammation recognition and healing ability. APD@RAW was monitored to cross the BBB and image deep brain inflamed areas in a model of acute brain inflammation. Meanwhile, the delivered Dex mitigated the brain damage caused by inflammatory cytokines secretion (IL-6, TNF-α, and IL-1β). Overall, this drug delivery system holds excellent potential for BBB penetrating and acute encephalitis therapies.

The Impressive Anti-Inflammatory Activity of Cerium Oxide Nanoparticles: More than Redox?

Cerium oxide nanoparticles (CNPs) are biocompatible nanozymes exerting multifunctional biomimetic activities, including superoxide dismutase (SOD), catalase, glutathione peroxidase, photolyase, and phosphatase. SOD- and catalase-mimesis depend on Ce3+/Ce4+ redox switch on nanoparticle surface, which allows scavenging the most noxious reactive oxygen species in a self-regenerating, energy-free manner. As oxidative stress plays pivotal roles in the pathogenesis of inflammatory disorders, CNPs have recently attracted attention as potential anti-inflammatory agents. A careful survey of the literature reveals that CNPs, alone or as constituents of implants and scaffolds, strongly contrast chronic inflammation (including neurodegenerative and autoimmune diseases, liver steatosis, gastrointestinal disorders), infections, and trauma, thereby ameliorating/restoring organ function. By general consensus, CNPs inhibit inflammation cues while boosting the pro-resolving anti-inflammatory signaling pathways. The mechanism of CNPs' anti-inflammatory effects has hardly been investigated, being rather deductively attributed to CNP-induced ROS scavenging. However, CNPs are multi-functional nanozymes that exert additional bioactivities independent from the Ce3+/Ce4+ redox switch, such as phosphatase activity, which could conceivably mediate some of the anti-inflammatory effects reported, suggesting that CNPs fight inflammation via pleiotropic actions. Since CNP anti-inflammatory activity is potentially a pharmacological breakthrough, it is important to precisely attribute the described effects to one or another of their nanozyme functions, thus achieving therapeutic credibility.

Role of Nanoparticle-Conjugates and Nanotheranostics in Abrogating Oxidative Stress and Ameliorating Neuroinflammation

Oxidative stress is a deteriorating condition that arises due to an imbalance between the reactive oxygen species and the antioxidant system or defense of the body. The key reasons for the development of such conditions are malfunctioning of various cell organelles, such as mitochondria, endoplasmic reticulum, and Golgi complex, as well as physical and mental disturbances. The nervous system has a relatively high utilization of oxygen, thus making it particularly vulnerable to oxidative stress, which eventually leads to neuronal atrophy and death. This advances the development of neuroinflammation and neurodegeneration-associated disorders such as Alzheimer's disease, Parkinson's disease, epilepsy, dementia, and other memory disorders. It is imperative to treat such conditions as early as possible before they worsen and progress to irreversible damage. Oxidative damage can be negated by two mechanisms: improving the cellular defense system or providing exogenous antioxidants. Natural antioxidants can normally handle such oxidative stress, but they have limited efficacy. The valuable features of nanoparticles and/or nanomaterials, in combination with antioxidant features, offer innovative nanotheranostic tools as potential therapeutic modalities. Hence, this review aims to represent novel therapeutic approaches like utilizing nanoparticles with antioxidant properties and nanotheranostics as delivery systems for potential therapeutic applications in various neuroinflammation- and neurodegeneration-associated disease conditions.

A pH-responsive ZC-QPP hydrogel for synergistic antibacterial and antioxidant treatment to enhance wound healing

The problems of bacterial resistance and high oxidation level severely limit wound healing. Therefore, we constructed a multifunctional platform of chitosan quaternary ammonium salts (QCS)/polyvinyl alcohol (PVA)/polyethylene glycol (PEG) hydrogels (QPP) loaded with ZnO@CeO2 (ZC-QPP). Firstly, the hydrogel was co-cross-linked by hydrogen and borate ester bonds, which allows easy adherence to a tissue surface for offering a protective barrier and moist environment for wounds. The chitosan quaternary ammonium salts due to their amino groups have inherent antibacterial properties to induce bacterial death. In response to the acidic conditions of the bacterial infection microenvironment, the borate ester bonds in the QPP hydrogel break and the ZC NCs dispersed in the hydrogel are released. The gradual dissociation of Zn2+ under acidic conditions can directly damage bacterial membranes. The wound site of bacterial infection always causes overexpression of reactive oxygen species (ROS) levels, often leading to inflammation and preventing rapid wound repair. CeO2 can eliminate excess ROS to reduce the inflammatory response. From in vitro and in vivo results, the high biosafety of the ZC-QPP hydrogel has demonstrated excellent antibacterial and antioxidant performance to enhance wound healing. Therefore, the ZC-QPP hydrogel opens a method to develop multifunctional synergistic therapeutic platforms combining enzyme-like nanomaterials with hydrogels for synergistic antibacterial and antioxidant treatment to promote wound healing.

Stem cell-derived hepatocyte therapy using versatile biomimetic nanozyme incorporated nanofiber-reinforced decellularized extracellular matrix hydrogels for the treatment of acute liver failure

Reactive oxygen species (ROS)-associated oxidative stress, inflammation storm, and massive hepatocyte necrosis are the typical manifestations of acute liver failure (ALF), therefore specific therapeutic interventions are essential for the devastating disease. Here, we developed a platform consisting of versatile biomimetic copper oxide nanozymes (Cu NZs)-loaded PLGA nanofibers (Cu NZs@PLGA nanofibers) and decellularized extracellular matrix (dECM) hydrogels for delivery of human adipose-derived mesenchymal stem/stromal cells-derived hepatocyte-like cells (hADMSCs-derived HLCs) (HLCs/Cu NZs@fiber/dECM). Cu NZs@PLGA nanofibers could conspicuously scavenge excessive ROS at the early stage of ALF, and reduce the massive accumulation of pro-inflammatory cytokines, herein efficiently preventing the deterioration of hepatocytes necrosis. Moreover, Cu NZs@PLGA nanofibers also exhibited a cytoprotection effect on the transplanted HLCs. Meanwhile, HLCs with hepatic-specific biofunctions and anti-inflammatory activity acted as a promising alternative cell source for ALF therapy. The dECM hydrogels further provided the desirable 3D environment and favorably improved the hepatic functions of HLCs. In addition, the pro-angiogenesis activity of Cu NZs@PLGA nanofibers also facilitated the integration of the whole implant with the host liver. Hence, HLCs/Cu NZs@fiber/dECM performed excellent synergistic therapeutic efficacy on ALF mice. This strategy using Cu NZs@PLGA nanofiber-reinforced dECM hydrogels for HLCs in situ delivery is a promising approach for ALF therapy and shows great potential for clinical translation.

Integration of MyD88 inhibitor into mesoporous cerium oxide nanozymes-based targeted delivery platform for enhancing treatment of ulcerative colitis

Excessive reactive oxygen species (ROS) and stressed inflammatory response are major characteristics of ulcerative colitis, which cause disease progression and aggravation. Herein, a novel mesoporous cerium oxide nanozymes (MCN) was designed and then loaded with Myeloid differentiation factor-88 (MyD88) inhibitor for synergistic treatment of colitis by scavenging ROS and regulating inflammation. This innovative MCN with average particle size of 200.7 nm, specific surface area of 119.78 m2/g and mesopores of 4.47 nm not only exhibited excellent SOD-like and CAT-like activities to scavenge ROS but also could act as a carrier to load MyD88 inhibitor, TJ-M2010-5, (abbreviated as TJ-5) into their mesopores, achieving the effect of 'two birds with one stone'. Besides, the modification of dextran sulfate sodium (TJ-5/MCN/DSS) increased the internalization of nanozymes into activated macrophages and enhanced in vitro anti-inflammatory ability. To enhance colon targeting, we coated TJ-5/MCN/DSS with the enteric material Eudragit S100, preventing premature release or absorption of the drug in the gastrointestinal tract after oral administration. The results demonstrated that TJ-5/MCN/DSS/Eudragit not only achieved delayed drug release and improved colon targeting but also exhibited optimal therapeutic efficacy in colitis mice. Mechanistically, the MCN-mediated ROS scavenging and TJ-5-mediated MyD88 blockade synergistically inhibited the NF-κB signaling pathway, thereby reducing the inflammatory response. Importantly, TJ-5/MCN/DSS/Eudragit did not induce systemic toxicity. In conclusion, our work not only presents a novel carrier capable of scavenging ROS but also provides proof of concept for the synergistic treatment of colitis using this carrier in combination with MyD88 inhibitors. This study proposes a safe and efficient strategy for targeting ROS-associated inflammation.

Ultrathin Niobium Carbide MXenzyme for Remedying Hypertension by Antioxidative and Neuroprotective Actions

Hypertension, as a leading risk factor for cardiovascular diseases, is associated with oxidative stress and impairment of endogenous antioxidant mechanisms, but there is still a tremendous knowledge gap between hypertension treatment and nanomedicines. Herein, we report a specific nanozyme based on ultrathin two-dimensional (2D) niobium carbide (Nb2 C) MXene, termed Nb2 C MXenzyme, to fight against hypertension by achieving highly efficient reactive oxygen species elimination and inflammatory factors inhibition. The biocompatible Nb2 C MXenzyme displays multiple enzyme-mimicking activities, involving superoxide dismutase, catalase, glutathione peroxidase, and peroxidase, inducing cytoprotective effects by resisting oxidative stress, thereby alleviating inflammatory response and reducing blood pressure, which is systematically demonstrated in a stress-induced hypertension rat model. This strategy not only opens new opportunities for nanozymes to treat hypertension but also expands the potential biomedical applications of 2D MXene nanosystems.

Nanomaterial-based contrast agents

Medical imaging, which empowers the detection of physiological and pathological processes within living subjects, has a vital role in both preclinical and clinical diagnostics. Contrast agents are often needed to accompany anatomical data with functional information or to provide phenotyping of the disease in question. Many newly emerging contrast agents are based on nanomaterials as their high payloads, unique physicochemical properties, improved sensitivity and multimodality capacity are highly desired for many advanced forms of bioimaging techniques and applications. Here, we review the developments in the field of nanomaterial-based contrast agents. We outline important nanomaterial design considerations and discuss the effect on their physicochemical attributes, contrast properties and biological behaviour. We also describe commonly used approaches for formulating, functionalizing and characterizing these nanomaterials. Key applications are highlighted by categorizing nanomaterials on the basis of their X-ray, magnetic, nuclear, optical and/or photoacoustic contrast properties. Finally, we offer our perspectives on current challenges and emerging research topics as well as expectations for future advancements in the field.

Protective Effects of Nanoceria against Mitochondrial Dysfunction and Angiotensin II-Induced Hypertrophy in H9c2 Cardiomyoblasts

Mitochondrial dysfunction triggered by increased reactive oxygen species (ROS) generation is involved in the pathogenesis and development of cardiac hypertrophy. Nanoceria (cerium oxide nanoparticle) has powerful ROS-scavenging properties and is considered a potential therapeutic option for curbing ROS-related disorders. Here, we explored the signaling mechanism underlying the protective effects of nanoceria against angiotensin (Ang) II-stimulated pathological response in H9c2 cardiomyoblasts. Our data revealed that pretreatment of H9c2 cardiomyoblasts with nanoceria significantly prevented Ang II-stimulated generation of intracellular ROS, aberrant expression of pro-inflammatory cytokines, and hypertrophy markers. Nanoceria pretreatment increased the mRNA levels of genes regulating the cellular antioxidant defense system (SOD2, MnSOD, CAT) in Ang II-treated cells. Furthermore, nanoceria restored mitochondrial function by decreasing mitochondrial ROS, increasing mitochondrial membrane potential (MMP), and promoting the mRNA expression of genes associated with mitochondrial biogenesis (PGC-1α, TFAM, NRF1, and SIRT3) and mitochondrial fusion (MFN2, OPA1). Collectively, these findings demonstrate the protective effects of nanoceria against Ang II-mediated mitochondrial dysfunction and pathological hypertrophy in H9c2 cells.

Nanomaterial-based Reactive Oxygen Species Scavengers for Osteoarthritis Therapy

Reactive oxygen species (ROS) play distinct but important roles in physiological and pathophysiological processes. Recent studies on osteoarthritis (OA) have suggested that ROS plays a crucial role in its development and progression, serving as key mediators in the degradation of the extracellular matrix, mitochondrial dysfunction, chondrocyte apoptosis, and OA progression. With the continuous development of nanomaterial technology, the ROS-scavenging ability and antioxidant effects of nanomaterials are being explored, with promising results already achieved in OA treatment. However, current research on nanomaterials as ROS scavengers for OA is relatively non-uniform and includes both inorganic and functionalized organic nanomaterials. Although the therapeutic efficacy of nanomaterials has been reported to be conclusive, there is still no uniformity in the timing and potential of their use in clinical practice. This paper reviews the nanomaterials currently used as ROS scavengers for OA treatment, along with their mechanisms of action, with the aim of providing a reference and direction for similar studies, and ultimately promoting the early clinical use of nanomaterials for OA treatment. STATEMENT OF SIGNIFICANCE: Reactive oxygen species (ROS) play an important role in the pathogenesis of osteoarthritis (OA). Nanomaterials serving as promising ROS scavengers have gained increasing attention in recent years. This review provides a comprehensive overview of ROS production and regulation, as well as their role in OA pathogenesis. Furthermore, this review highlights the applications of various types of nanomaterials as ROS scavengers in OA treatment and their mechanisms of action. Finally, the challenges and future prospects of nanomaterial-based ROS scavengers in OA therapy are discussed.

Cerium oxide nanoparticles protect against chondrocytes and cartilage explants from oxidative stress via Nrf2/HO-1 pathway in temporomandibular joint osteoarthritis

Oxidative stress is closely linked to the etiology of temporomandibular joint osteoarthritis. (TMJ-OA) and is an important therapeutic target. Cerium oxide nanoparticles (CNPs) have been broadly studied owing to their powerful antioxidant properties and potential preventive and therapeutic effects against chronic diseases. The current study was designed to explore the protective effects of CNPs on the progression of TMJ-OA and their potential mechanisms. We detected the ability of CNPs to eliminate reactive oxygen species (ROS) in chondrocytes. Moreover, their protective effects on chondrocytes were detected in the level of gene and protein. Furthermore, TUNEL assay, histology and safranin O-fast green staining were used to detect the beneficial effects of CNPs on cartilage explants. The mechanism of CNPs, protecting condylar cartilage by reducing inflammation, was further explored by knocking down the Nuclear factor-erythroid 2-related factor (Nrf2) gene. CNPs could reduce the ROS levels in chondrocytes and cartilage explants and reverse the IL-1β-induced imbalance of cartilage matrix metabolism and apoptosis. The protective effects of CNPs on cartilage were lost after key antioxidant factors including Nrf2 and heme-oxygenase 1(HO-1) were significantly reduced. In conclusion, this study demonstrated for the first time that activating the Nrf2/HO-1 signaling pathway by CNPs might have therapeutic potential for TMJ-OA.

Induction of Innate Memory in Human Monocytes Exposed to Mixtures of Bacterial Agents and Nanoparticles

We assessed whether concomitant exposure of human monocytes to bacterial agents and different engineered nanoparticles can affect the induction of protective innate memory, an immune mechanism that affords better resistance to diverse threatening challenges. Monocytes were exposed in vitro to nanoparticles of different chemical nature, shape and size either alone or admixed with LPS, and cell activation was assessed in terms of production of inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10, IL-1Ra). After return to baseline conditions, cells were re-challenged with LPS and their secondary "memory" response measured. Results show that nanoparticles alone are essentially unable to generate memory, while LPS induced a tolerance memory response (less inflammatory cytokines, equal or increased anti-inflammatory cytokines). LPS-induced tolerance was not significantly affected by the presence of nanoparticles during the memory generation phase, although with substantial donor-to-donor variability. This suggests that, despite the overall lack of significant effects on LPS-induced innate memory, nanoparticles may have donor-specific effects. Thus, future nanosafety assessment and nanotherapeutic strategies will need a personalized approach in order to ensure both the safety and efficacy of nano medical compounds for individual patients.

Nanozymes in the Treatment of Diseases Caused by Excessive Reactive Oxygen Specie

Excessive reactive oxygen species (ROS) may generate deleterious effects on biomolecules, such as DNA damage, protein oxidation and lipid peroxidation, causing cell and tissue damage and eventually leading to the pathogenesis of diseases, such as neurodegenerative diseases, ischemia/reperfusion ((I/R)) injury, and inflammatory diseases. Therefore, the modulation of ROS can be an efficient means to relieve the aforementioned diseases. Several studies have verified that antioxidants such as Mitoquinone (a mitochondrial-targeted coenzyme Q10 derivative) can scavenge ROS and attenuate related diseases. Nanozymes, defined as nanomaterials with intrinsic enzyme-like properties that also possess antioxidant properties, are hence expected to be promising alternatives for the treatment of ROS-related diseases. This review introduces the types of nanozymes with inherent antioxidant activities, elaborates on various strategies (eg, controlling the size or shape of nanozymes, regulating the composition of nanozymes and environmental factors) for modulating their catalytic activities, and summarizes their performances in treating ROS-induced diseases.

Nanotechnology strategies for hepatocellular carcinoma diagnosis and treatment

Hepatocellular carcinoma (HCC) is a common malignancy threatening human health, and existing diagnostic and therapeutic techniques are facing great challenges. In the last decade or so, nanotechnology has been developed and improved for tumor diagnosis and treatment. For example, nano-intravenous injections have been approved for malignant perivascular epithelioid cell tumors. This article provides a comprehensive review of the applications of nanotechnology in HCC in recent years: (I) in radiological imaging, magnetic resonance imaging (MRI), fluorescence imaging (FMI) and multimodality imaging. (II) For diagnostic applications in HCC serum markers. (III) As embolic agents in transarterial chemoembolization (TACE) or directly as therapeutic drugs. (IV) For application in photothermal therapy and photodynamic therapy. (V) As carriers of chemotherapeutic drugs, targeted drugs, and natural plant drugs. (VI) For application in gene and immunotherapy. Compared with the traditional methods for diagnosis and treatment of HCC, nanoparticles have high sensitivity, reduce drug toxicity and have a long duration of action, and can also be combined with photothermal and photodynamic multimodal combination therapy. These summaries provide insights for the further development of nanotechnology applications in HCC.

Cerium Oxide Nanoparticles Alleviate Neuropathic Pain by Modulating Macrophage Polarization in a Rat SCI Model

Context

Chronic neuropathic pain (NP) frequently occurs after spinal cord injury (SCI) but lacks effective therapeutic options in the clinic. Numerous evidence indicates the involvement of macrophages activation in the NP, and the modulation of macrophages is promising for NP treatment. In this study, we introduce Cerium oxide nanoparticles (CONPs) and aim to investigate whether it can relieve the NP by modulating macrophage polarization.

Methods

CONPs were prepared using the hydrothermal method. In vitro, different concentrations of CONPs were used to cultivate macrophages (RAW 264.7). In vivo, the analgesic effect of CONPs was investigated in a contusive rat SCI model. Mechanical paw withdrawal threshold (PWT) and thermal paw withdrawal latency (PWL) were tested to evaluate pain behaviors. Immunofluorescence staining and real-time quantitative polymerase chain reaction were applied to assess macrophage phenotypes.

Results

The synthesized CONPs were 6.8 ± 0.5 nm in size, presenting a cubic morphology. Live/dead staining showed that the relatively low concentrations of CONPs (less than 800 μg/mL) displayed good biocompatibility with macrophages. Intrathecal injection of CONPs could significantly increase the mechanical PWT and thermal PWL of SCI rats. Molecular experiments results showed the expression of M2 macrophage-related markers (CD206, Arg-1, IL-10) were significantly increased, while that of M1 macrophage-related markers (CD86, TNF-α, iNOS) were downregulated after CONPs treatment.

Conclusion

Our study suggests that CONPs can relive the NP following SCI by promoting M2 macrophages polarization, which provides a novel insight for the treatment of SCI induced NP.