Different approaches to synthesising cerium oxide nanoparticles and their corresponding physical characteristics, and ROS scavenging and anti-inflammatory capabilities

Cerium Dioxide-Dextran Nanocomposites in the Development of a Medical Product for Wound Healing: Physical, Chemical and Biomedical Characteristics

PURPOSE OF THE STUDY

the creation of a dextran coating on cerium oxide crystals using different ratios of cerium and dextran to synthesize nanocomposites, and the selection of the best nanocomposite to develop a nanodrug that accelerates quality wound healing with a new type of antimicrobial effect.

MATERIALS AND METHODS

Nanocomposites were synthesized using cerium nitrate and dextran polysaccharide (6000 Da) at four different initial ratios of Ce(NO3)3x6H2O to dextran (by weight)-1:0.5 (Ce0.5D); 1:1 (Ce1D); 1:2 (Ce2D); and 1:3 (Ce3D). A series of physicochemical experiments were performed to characterize the created nanocomposites: UV-spectroscopy; X-ray phase analysis; transmission electron microscopy; dynamic light scattering and IR-spectroscopy. The biomedical effects of nanocomposites were studied on human fibroblast cell culture with an evaluation of their effect on the metabolic and proliferative activity of cells using an MTT test and direct cell counting. Antimicrobial activity was studied by mass spectrometry using gas chromatography-mass spectrometry against E. coli after 24 h and 48 h of co-incubation.

RESULTS

According to the physicochemical studies, nanocrystals less than 5 nm in size with diffraction peaks characteristic of cerium dioxide were identified in all synthesized nanocomposites. With increasing polysaccharide concentration, the particle size of cerium dioxide decreased, and the smallest nanoparticles (<2 nm) were in Ce2D and Ce3D composites. The results of cell experiments showed a high level of safety of dextran nanoceria, while the absence of cytotoxicity (100% cell survival rate) was established for Ce2D and C3D sols. At a nanoceria concentration of 10-2 M, the proliferative activity of fibroblasts was statistically significantly enhanced only when co-cultured with Ce2D, but decreased with Ce3D. The metabolic activity of fibroblasts after 72 h of co-cultivation with nano composites increased with increasing dextran concentration, and the highest level was registered in Ce3D; from the dextran group, differences were registered in Ce2D and Ce3D sols. As a result of the microbiological study, the best antimicrobial activity (bacteriostatic effect) was found for Ce0.5D and Ce2D, which significantly inhibited the multiplication of E. coli after 24 h by an average of 22-27%, and after 48 h, all nanocomposites suppressed the multiplication of E. coli by 58-77%, which was the most pronounced for Ce0.5D, Ce1D, and Ce2D.

CONCLUSIONS

The necessary physical characteristics of nanoceria-dextran nanocomposites that provide the best wound healing biological effects were determined. Ce2D at a concentration of 10-3 M, which stimulates cell proliferation and metabolism up to 2.5 times and allows a reduction in the rate of microorganism multiplication by three to four times, was selected for subsequent nanodrug creation.

In-situ growth of CeO2 on biofilms: Innovative nanoparticles for photothermal therapy & multi-pronged attack on Alzheimer's disease

Alzheimer's disease (AD) is complex and multifactorial, and its pathogenesis involves multiple factors and processes. This study pioneered the in situ growth of cerium oxide nanoparticles on macrophage membranes (Ce-RAW). Further, carbon quantum dots (CQD) were biomimetically modified by Ce-RAW, leading to the synthesis of a multifunctional nanocomposite (CQD-Ce-RAW). Within the framework of this research, CQD-Ce-RAW was strategically combined with photothermal therapy (PTT), aiming to achieve a more significant therapeutic effect. The macrophage membrane confers the system with anti-phagocytic and anti-inflammatory biological functions. More importantly, the ultra-small size of cerium oxide grown on the membrane acts as a reactive oxygen species (ROS) scavenger and alleviates the degree of oxidative stress. Meanwhile, CQD as a photosensitizer helps dissociate amyloid-β (Aβ) aggregates and chelates excess copper ions, thus further inhibiting Aβ aggregation. Cell experiments showed that CQD-Ce-RAW combined with PTT could effectively degrade and inhibit the aggregation of Aβ, remove ROS, and improve cell survival rate. The results of in vivo photothermal experiments demonstrated that near-infrared light enhanced the efficiency of drug penetration through the blood-brain barrier and facilitated its accumulation in brain tissue. This comprehensive therapeutic approach can intervene in the disease progression from multiple pathways, providing a new prospect for treating AD.

Ceria Nanoparticle Systems Alleviate Degenerative Changes in Mouse Postovulatory Aging Oocytes by Reducing Oxidative Stress and Improving Mitochondrial Functions

Postovulatory aging oocytes usually feature diminished potential for fertilization and poor embryonic development due to enhanced oxidative damage to the subcellular organelles and macromolecules, which stands as a formidable obstacle in assisted reproductive technologies (ART). Here, we developed lipoic acid (LA) and polyethylene glycol (PEG)-modified CeO2 nanoparticles (LA-PEG-CeNPs) with biocompatibility, enzyme-like autocatalytic activity, and free radical scavenging capacity. We further investigated the LA-PEG-CeNPs effect in mouse postovulatory oocytes during in vitro aging. The results showed that LA-PEG-CeNPs dramatically reduced the accumulation of ROS in aging oocytes, improving mitochondrial dysfunction; they also down-regulated the pro-apoptotic activity by rectifying cellular caspase-3, cleaved caspase-3, and Bcl-2 levels. Consistently, this nanoenzyme prominently alleviated the proportion of abnormalities in spindle structure, chromosome alignment, microtubule stability, and filamentous actin (F-actin) distribution in aging oocytes, furthermore decreased oocyte fragmentation, and improved its ability of fertilization and development to blastocyst. Taken together, our finding suggests that LA-PEG-CeNPs can alleviate oxidative stress damage on oocyte quality during postovulatory aging, implying their potential value for clinical practice in assisted reproduction.

Evaluating thrombosis risk and patient-specific treatment strategy using an atherothrombosis-on-chip model

Platelets play an essential role in thrombotic processes. Recent studies suggest a direct link between increased plasma glucose, lipids, and inflammatory cytokines with platelet activation and aggregation, resulting in an increased risk of atherothrombotic events in cardiovascular patients. Antiplatelet therapies are commonly used for the primary prevention of atherosclerosis. Transitioning from a population-based strategy to patient-specific care requires a better understanding of the risks and advantages of antiplatelet therapy for individuals. This proof-of-concept study evaluates the potential to assess an individual's risk of forming atherothrombosis using a dual-channel microfluidic model emulating multiple atherogenic factors in vitro, including high glucose, high cholesterol, and inflammatory cytokines along with stenosis vessel geometry. The model shows precise sensitivity toward increased plasma glucose, cholesterol, and tumour necrosis factor-alpha (TNF-α)-treated groups in thrombus formation. An in vivo-like dose-dependent increment in platelet aggregation is observed in different treated groups, benefiting the evaluation of thrombosis risk in the individual condition. Moreover, the model could help decide the effective dosing of aspirin in multi-factorial complexities. In the high glucose-treated group, a 50 μM dose of aspirin could significantly reduce platelet aggregation, while a 100 μM dose of aspirin was required to reduce platelet aggregation in the glucose-TNF-α-treated group, which proves the model's potentiality as a tailored tool for customised therapy.

Cerium Oxide Nanozymes Improve Skeletal Muscle Function in Gestational Diabetic Offspring by Attenuating Mitochondrial Oxidative Stress

Gestational diabetes mellitus (GDM) is a significant complication during pregnancy that results in abnormalities in the function of multiple systems in the offspring, which include skeletal muscle dysfunction and reduced systemic metabolic capacity. One of the primary causes behind this intergenerational effect is the presence of mitochondrial dysfunction and oxidative stress in the skeletal muscle of the offspring due to exposure to a high-glucose environment in utero. Cerium oxide (CeO2) nanozymes are antioxidant agents with polymerase activity that have been widely used in the treatment of inflammatory and aging diseases. In this study, we synthesized ultrasmall particle size CeO2 nanozymes and applied them in GDM mouse offspring. The CeO2 nanozymes demonstrated an ability to increase insulin sensitivity and enhance skeletal muscle motility in GDM offspring by improving mitochondrial activity, increasing mitochondrial ATP synthesis function, and restoring abnormal mitochondrial morphology. Furthermore, at the cellular level, CeO2 nanozymes could ameliorate metabolic dysregulation and decrease cell differentiation in adult muscle cells induced by hyperglycemic stimuli. This was achieved through the elimination of endogenous reactive oxygen species (ROS) and an improvement in mitochondrial oxidative respiration function. In conclusion, CeO2 nanozymes play a crucial role in preserving muscle function and maintaining the metabolic stability of organisms. Consequently, they serve to reverse the negative effects of GDM on skeletal muscle physiology in the offspring.

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.

Multifunctional nanocomposites mediated novel hydrogel for diabetic wound repair

The regeneration and repair of diabetic wounds, especially those including bacterial infection, have always been difficult and challenging using current treatment. Herein, an effective strategy is reported for constructing glucose-responsive functional hydrogels using nanocomposites as nodes. In fact, tannic acid (TA)-modified ceria nanocomposites (CNPs) and a zinc metal-organic framework (ZIF-8) were employed as nodes. Subsequent crosslinking with 3-acrylamidophenylboronic acid achieved functional nanocomposite-hydrogels (TA@CN gel, TA@ZMG gel) by radical-mediated polymerization. Compared with a simple physically mixed hydrogel system, the mechanical properties of TA@CN gel and TA@ZMG gel are significantly enhanced due to the intervention of the nanocomposite nodes. In addition, this kind of nanocomposite hydrogel can realize the programmed loading of drugs and release of drugs in response to glucose/PH, to coordinate and promote its application in the regeneration and repair of diabetic wounds and infected diabetic wounds. Specifically, TA@CN gel can remove reactive oxygen species and generate oxygen through its various enzymatic activities. At the same time, it can effectively promote neovascularization, thus promoting the regeneration and repair of diabetic wounds. Furthermore, glucose oxidase-loaded TA@ZMG gel exhibits glucose response and pH-regulating functions, triggering programmed metformin (Met) release by degrading the metal-organic framework (MOF) backbone. It also exhibited additional synergistic effects of antibacterial activity, hair regeneration and systemic blood glucose regulation, which make it suitable for the repair of more complex infected diabetic wounds. Overall, this novel nanocomposite-mediated hydrogel holds great potential as a biomaterial for the healing of chronic diabetic wounds, opening up new avenues for further biomedical applications.

Study on chitosan/gelatin hydrogels containing ceria nanoparticles for promoting the healing of diabetic wound

Chronic inflammation at diabetic wound sites results in the uncontrolled accumulation of pro-inflammatory factors and reactive oxygen species (ROS), which impedes cell proliferation and delays wound healing. To promote the healing of diabetic wounds, chitosan/gelatin hydrogels containing ceria nanoparticles (CNPs) of various sizes were created in the current study. CNPs' efficacy in removingO 2 • - $$ {\mathrm{O}}_2^{\bullet -} $$ , •OH, and H2 O2 was demonstrated, and the scavenging ability of CNPs of varying sizes was compared. The in vitro experiments demonstrated that hydrogels containing CNPs could effectively protect cells from ROS-induced damage and facilitate mouse fibroblast migration. Furthermore, during the treatment of diabetic wounds in vivo, hydrogels containing CNPs exhibited anti-inflammatory activity and could reduce the expression of the pro-inflammatory factors TNF-α (above 30%), IL-6 (above 90%), and IL-1β (above 80%), and effectively promote wound closure (above 80%) by inducing re-epithelialization, collagen deposition, and angiogenesis. In addition, the biological properties and therapeutic effects of hydrogels containing CNPs of various sizes were compared and discussed. The finding revealed that hydrogels with 4 nm CNPs exhibited more significant biological properties and had implications for diabetic wound treatment.

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.

Antimicrobial Activity of Citrate-Coated Cerium Oxide Nanoparticles

The purpose of this study was to investigate the antimicrobial activity of citrate-stabilized sols of cerium oxide nanoparticles at different concentrations via different microbiological methods and to compare the effect with the peroxidase activity of nanoceria for the subsequent development of a regeneration-stimulating medical and/or veterinary wound-healing product providing new types of antimicrobial action. The object of this study was cerium oxide nanoparticles synthesized from aqueous solutions of cerium (III) nitrate hexahydrate and citric acid (the size of the nanoparticles was 3-5 nm, and their aggregates were 60-130 nm). Nanoceria oxide sols with a wide range of concentrations (10-1-10-6 M) as well as powder (the dry substance) were used. Both bacterial and fungal strains (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris, Candida albicans, Aspergillus brasielensis) were used for the microbiological studies. The antimicrobial activity of nanoceria was investigated across a wide range of concentrations using three methods sequentially; the antimicrobial activity was studied by examining diffusion into agar, the serial dilution method was used to detect the minimum inhibitory and bactericidal concentrations, and, finally, gas chromatography with mass-selective detection was performed to study the inhibition of E. coli's growth. To study the redox activity of different concentrations of nanocerium, we studied the intensity of chemiluminescence in the oxidation reaction of luminol in the presence of hydrogen peroxide. As a result of this study's use of the agar diffusion and serial dilution methods followed by sowing, no significant evidence of antimicrobial activity was found. At the same time, in the current study of antimicrobial activity against E. coli strains using gas chromatography with mass spectrometry, the ability of nanoceria to significantly inhibit the growth and reproduction of microorganisms after 24 h and, in particular, after 48 h of incubation at a wide range of concentrations, 10-2-10-5 M (48-95% reduction in the number of microbes with a significant dose-dependent effect) was determined as the optimum concentration. A reliable redox activity of nanoceria coated with citrate was established, increasing in proportion to the concentration, confirming the oxidative mechanism of the action of nanoceria. Thus, nanoceria have a dose-dependent bacteriostatic effect, which is most pronounced at concentrations of 10-2-10-3 M. Unlike the effects of classical antiseptics, the effect was manifested from 2 days and increased during the observation. To study the antimicrobial activity of nanomaterials, it is advisable not to use classical qualitative and semi-quantitative methods; rather, the employment of more accurate quantitative methods is advised, in particular, gas chromatography-mass spectrometry, during several days of incubation.

Anti-Acidification and Immune Regulation by Nano-Ceria-Loaded Mg-Al Layered Double Hydroxide for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a chronic autoimmune disease featuring an abnormal immune microenvironment and resultant accumulation of hydrogen ions (H+ ) produced by activated osteoclasts (OCs). Currently, clinic RA therapy can hardly achieve sustained or efficient therapeutic outcomes due to the failures in generating sufficient immune modulation and manipulating the accumulation of H+ that deteriorates bone damage. Herein, a highly effective immune modulatory nanocatalytic platform, nanoceria-loaded magnesium aluminum layered double hydroxide (LDH-CeO2 ), is proposed for enhanced immune modulation based on acid neutralization and metal ion inherent bioactivity. Specifically, the mild alkaline LDH initiates significant M2 repolarization of macrophages triggered by the elevated antioxidation effect of CeO2 via neutralizing excessive H+ in RA microenvironment, thus resulting in the efficient recruitment of regulatory T cell (Treg) and suppressions on T helper 17 cell (Th 17) and plasma cells. Moreover, the osteogenic activity is stimulated by the Mg ion released from LDH, thereby promoting the damaged bone healing. The encouraging therapeutic outcomes in adjuvant-induced RA model mice demonstrate the high feasibility of such a therapeutic concept, which provides a novel and efficient RA therapeutic modality by the immune modulatory and bone-repairing effects of inorganic nanocatalytic material.

Low-Index Facet Polyhedron-Shaped Binary Cerium Titanium Oxide for High-Voltage Aqueous Zinc-Vanadium Redox Flow Batteries

Aqueous zinc-vanadium hybrid redox flow battery systems are an efficient strategy to address the problems of low voltage and high cost of conventional all-vanadium redox flow batteries. However, the low electrochemical activity of carbon-based electrodes toward a vanadium redox reaction limits the performance of redox flow batteries. In this study, polyhedral binary cerium titanium oxide (Ce2/3TiO3, CTO) is synthesized using molten salt synthesis. CTO is fabricated by adjusting the temperature and composition. Notably, the prepared CTO obtained at 1000 °C shows the highest catalytic activity for a VO2+/VO2+ redox reaction. Further, CTO is prepared as a composite electrocatalyst and applied to a high-voltage aqueous zinc-vanadium redox flow battery. The cell adopts an alkali zinc electrolyte containing a Zn/[Zn(OH)4]2- redox pair and exhibits a high operating voltage of 2.26 V. Remarkably, a zinc-vanadium redox flow battery using the composite electrocatalyst exhibits a high energy density of 42.68 Wh L-1 at 20 mA cm-2 and an initial voltage efficiency of 90.3%. The excellent cell performance is attributed to structural defects caused by A-site deficiency in the perovskite oxide structure as well as oxygen vacancies resulting from the low valence state of the metal ion, which enhance the catalytic activity of the vanadium ions.

Reactive oxygen species (ROS) scavenging biomaterials for anti-inflammatory diseases: from mechanism to therapy

Inflammation is a fundamental defensive response to harmful stimuli, but the overactivation of inflammatory responses is associated with most human diseases. Reactive oxygen species (ROS) are a class of chemicals that are generated after the incomplete reduction of molecular oxygen. At moderate levels, ROS function as critical signaling molecules in the modulation of various physiological functions, including inflammatory responses. However, at excessive levels, ROS exert toxic effects and directly oxidize biological macromolecules, such as proteins, nucleic acids and lipids, further exacerbating the development of inflammatory responses and causing various inflammatory diseases. Therefore, designing and manufacturing biomaterials that scavenge ROS has emerged an important approach for restoring ROS homeostasis, limiting inflammatory responses and protecting the host against damage. This review systematically outlines the dynamic balance of ROS production and clearance under physiological conditions. We focus on the mechanisms by which ROS regulate cell signaling proteins and how these cell signaling proteins further affect inflammation. Furthermore, we discuss the use of potential and currently available-biomaterials that scavenge ROS, including agents that were engineered to reduce ROS levels by blocking ROS generation, directly chemically reacting with ROS, or catalytically accelerating ROS clearance, in the treatment of inflammatory diseases. Finally, we evaluate the challenges and prospects for the controlled production and material design of ROS scavenging biomaterials.

Targeting endothelial vascular cell adhesion molecule-1 in atherosclerosis: drug discovery and development of vascular cell adhesion molecule-1-directed novel therapeutics

Vascular cell adhesion molecule-1 (VCAM-1) has been well established as a critical contributor to atherosclerosis and consequently as an attractive therapeutic target for anti-atherosclerotic drug candidates. Many publications have demonstrated that disrupting the VCAM-1 function blocks monocyte infiltration into the sub-endothelial space, which effectively prevents macrophage maturation and foam cell transformation necessary for atherosclerotic lesion formation. Currently, most VCAM-1-inhibiting drug candidates in pre-clinical and clinical testing do not directly target VCAM-1 itself but rather down-regulate its expression by inhibiting upstream cytokines and transcriptional regulators. However, the pleiotropic nature of these regulators within innate immunity means that optimizing dosage to a level that suppresses pathological activity while preserving normal physiological function is extremely challenging and oftentimes infeasible. In recent years, highly specific pharmacological strategies that selectively inhibit VCAM-1 function have emerged, particularly peptide- and antibody-based novel therapeutics. Studies in such VCAM-1-directed therapies so far remain scarce and are limited by the constraints of current experimental atherosclerosis models in accurately representing the complex pathophysiology of the disease. This has prompted the need for a comprehensive review that recounts the evolution of VCAM-1-directed pharmaceuticals and addresses the current challenges in novel anti-atherosclerotic drug development.

A Bioactive Disintegrable Polymer Nanoparticle for Synergistic Vascular Anticalcification

Although poly(aspartic acid) (PASP), a strong calcium chelating agent, may be potentially effective in inhibition of vascular calcification, its direct administration may lead to side effects. In this study, we employed polysuccinimide, a precursor of PASP, to prepare targeted polysuccinimide-based nanoparticles (PSI NPs) that not only acted as a prodrug but also functioned as a carrier of additional therapeutics to provide powerful synergistic vascular anticalcification effect. This paper shows that chemically modified PSI-NPs can serve as effective nanocarriers for loading of hydrophobic drugs, in addition to anticalcification and antireactive oxygen species (anti-ROS) activities. Curcumin (Cur), with high loading efficiency, was encapsulated into the NPs. The NPs were stable for 16 h in physiological conditions and then slowly dissolved/hydrolyzed to release the therapeutic PASP and the encapsulated drug. The drug release profile was found to be in good agreement with the NP dissolution profile such that complete release occurred after 48 h at physiological conditions. However, under acidic conditions, the NPs were stable, and Cur cumulative release reached only 30% after 1 week. Though highly effective in the prevention of calcium deposition, PSI NPs could not prevent the osteogenic trans-differentiation of vascular smooth muscle cells (VSMCs). The presence of Cur addressed this problem. It not only further reduced ROS level in macrophages but also prevented osteogenic differentiation of VSMCs in vitro. The NPs were examined in vivo in a rat model of vascular calcification induced by kidney failure through an adenine diet. The inclusion of Cur and PSI NPs combined the therapeutic effects of both. Cur-loaded NPs significantly reduced calcium deposition in the aorta without adversely affecting bone integrity or noticeable side effects/toxicity as examined by organ histological and serum biochemistry analyses.

Advances in drug delivery to atherosclerosis: Investigating the efficiency of different nanomaterials employed for different type of drugs

Atherosclerosis is the build-up of fatty deposits in the arteries, which is the main underlying cause of cardiovascular diseases and the leading cause of global morbidity and mortality. Current pharmaceutical treatment options are unable to effectively treat the plaque in the later stages of the disease. Instead, they are aimed at resolving the risk factors. Nanomaterials and nanoparticle-mediated therapies have become increasingly popular for the treatment of atherosclerosis due to their targeted and controlled release of therapeutics. In this review, we discuss different types of therapeutics used to treat this disease and focus on the different nanomaterial strategies employed for the delivery of these drugs, enabling the effective and efficient resolution of the atherosclerotic plaque. The ideal nanomaterial strategy for each drug type (e.g. statins, nucleic acids, small molecule drugs, peptides) will be comprehensively discussed.

Influence of the Synthesis Scheme of Nanocrystalline Cerium Oxide and Its Concentration on the Biological Activity of Cells Providing Wound Regeneration

In the ongoing search for practical uses of rare-earth metal nanoparticles, cerium dioxide nanoparticles (nanoceria) have received special attention. The purpose of this research was to study the biomedical effects of nanocrystalline forms of cerium oxide obtained by different synthesis schemes and to evaluate the effect of different concentrations of nanoceria (from 10-2 to 10-6 M) on cells involved in the regeneration of skin cell structures such as fibroblasts, mesenchymal stem cells, and keratinocytes. Two different methods of nanoceria preparation were investigated: (1) CeO-NPs-1 by precipitation from aqueous solutions of cerium (III) nitrate hexahydrate and citric acid and (2) CeO-NPs-2 by hydrolysis of ammonium hexanitratocerate (IV) under conditions of thermal autoclaving. According to the X-ray diffraction, transmission electron microscopy, and dynamic light scattering data, CeO2-1 consists of individual particles of cerium dioxide (3-5 nm) and their aggregates with diameters of 60-130 nm. CeO2-2 comprises small aggregates of 8-20 nm in diameter, which consist of particles of 2-3 nm in size. Cell cultures of human fibroblasts, human mesenchymal stem cells, and human keratinocytes were cocultured with different concentrations of nanoceria sols (10-2, 10-3, 10-4, 10-5, and 10-6 mol/L). The metabolic activity of all cell types was investigated by MTT test after 48 and 72 h, whereas proliferative activity and cytotoxicity were determined by quantitative cell culture counting and live/dead test. A dependence of biological effects on the method of nanoceria preparation and concentration was revealed. Data were obtained with respect to the optimal concentration of sol to achieve the highest metabolic effect in the used cell cultures. Hypotheses about the mechanisms of the obtained effects and the structure of a fundamentally new medical device for accelerated healing of skin wounds were formulated. The method of nanoceria synthesis and concentration fundamentally and significantly change the biological activity of cell cultures of different types-from suppression to pronounced stimulation. The best biological activity of cell cultures was determined through cocultivation with sols of citrate nanoceria (CeO-NPs-1) at a concentration of 10-3-10-4 M.

A Versatile PDA(DOX) Nanoplatform for Chemo-Photothermal Synergistic Therapy against Breast Cancer and Attenuated Doxorubicin-Induced Cardiotoxicity

Photothermal therapy (PTT) is a highly clinical application promising cancer treatment strategy with safe, convenient surgical procedures and excellent therapeutic efficacy on superficial tumors. However, a single PTT is difficult to eliminate tumor cells completely, and tumor recurrence and metastasis are prone to occur in the later stage. Chemo-photothermal synergistic therapy can conquer the shortcomings by further killing residual tumor cells after PTT through systemic chemotherapy. Nevertheless, chemotherapy drugs' extreme toxicity is also a problematic issue to be solved, such as anthracycline-induced cardiotoxicity. Herein, we selected polydopamine nanoparticles (PDA) as the carrier of the chemotherapeutic drug doxorubicin (DOX) to construct a versatile PDA(DOX) nanoplatform for chemo-photothermal synergistic therapy against breast cancer and simultaneously attenuated DOX-induced cardiotoxicity (DIC). The excellent photothermal properties of PDA were used to achieve the thermal ablation of tumors. DOX carried out chemotherapy to kill residual and occult distant tumors. Furthermore, the PDA(DOX) nanoparticles significantly alleviate DIC, which benefits from PDA's excellent antioxidant enzyme activity. The experimental data of the chemotherapy groups showed that the results of the PDA(DOX) group were much better than the DOX group. This study not only effectively inhibits cancer but tactfully attenuates DIC, bringing a new perspective into synergistic therapy against breast cancer.

Photothermal effective CeO2NPs combined in thermosensitive hydrogels with enhanced antibacterial, antioxidant and vascularization performance to accelerate infected diabetic wound healing

Chronic diabetic wound healing remains a formidable challenge due to susceptibility to bacterial infection, excessive oxidative stress, and poor angiogenesis. To address these issues, a sodium alginate (SA) based photothermal hydrogel dressing with multifunction was fabricated to facilitate wound treatment. Ceria nanoparticles (CeO2NPs) was synthesized, and their antibacterial performance by near-infrared light triggered photothermal effects was first studied and verified in this work. In addition, to release CeO2NPs to achieve antioxidation and pro-vascularization, thermosensitive gelatin (Gel) was utilized to embed the nanoparticles in advance and then composited in SA hydrogel networks. SA network was finally strengthened by acid soaking to form partially crystalline regions to act as natural crosslinkers. Results showed that the Gel/SA/CeO2 hydrogel displayed temperature-responsive release of CeO2NPs, significant antibacterial and antioxidative activity, as well as the ability to remove without injury and promote infected diabetic wound healing with low cytotoxicity, according to antibacterial investigations, cell studies, and in vivo animal studies. This research offers not only a successful method for quickening the healing of diabetic wounds but also a fresh approach to the general use of CeO2NPs.

Polydopamine Modified Ceria Nanorods Alleviate Inflammation in Colitis by Scavenging ROS and Regulating Macrophage M2 Polarization

Background

Inflammatory bowel disease (IBD) is closely related to higher intracellular oxidative stress. Therefore, developing a novel method to scavenge the harmful reactive oxygen species (ROS) and alleviate colon inflammation to treat IBD is a promising strategy.

Methods

CeO2@PDA-PEG (CeO2@PP) were synthesized by modifying ceria (CeO2) nanorods with polydopamine (PDA) and polyethylene glycol (PEG). The ROS scavenging ability of CeO2@PP was detected by using flow cytometry and confocal laser scanning microscope (CLSM). The anti-inflammatory ability of CeO2@PP was determined in vitro by treating lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The biocompatibility of CeO2@PP was evaluated in vivo and in vitro. Moreover, the therapeutic effects of CeO2@PP in vivo were estimated in a dextran sulfate sodium salt (DSS)-induced colitis mouse model.

Results

Physicochemical property results demonstrated that PDA and PEG modification endowed CeO2 nanorods with excellent dispersibility and colloidal stability. CeO2@PP maintained superior enzyme-like activity, including superoxide dismutase (SOD) and catalase (CAT), indicating antioxidant ability. Moreover, in vitro results showed that CeO2@PP with PDA promotes LPS-induced RAW 264.7 macrophages into M2-type polarization. In addition, in vitro and in vivo results showed that CeO2@PP have great biocompatibility and biosafety. Animal experiments have shown that CeO2@PP have excellent anti-inflammatory effects against DSS-induced colitis and effectively alleviated intestinal mucosal injury.

Conclusion

The nanoplatform CeO2@PP possessed excellent antioxidant and anti-inflammatory properties for scavenging ROS and modulating macrophage polarization, which is beneficial for efficient colitis therapy.

A brief study on the role of cerium oxide nanoparticles in growth and alleviation of mercury-induced stress in Vigna radiata and soil bacteria Bacillus coagulans

Cerium oxide nanoparticles have so far been investigated for their role as an antioxidant in pathologies involving inflammation and high oxidative stress. However, its role as a plant and bacterial growth modulator and heavy metal stress reliever has been overlooked to date. Heavy metal contamination poses a major threat to mankind and the life-sustaining ecosystem. This study emphasizes the role of cerium oxide produced by the combustion method in promoting growth in Vigna radiata and Bacillus coagulans in the presence of mercury. The results show that cerium oxide nanoparticles significantly reduce the production of reactive oxygen species, hydrogen peroxide, and product of lipid peroxidation malondialdehyde in plants grown in the presence of 50 ppm mercury, thereby reducing oxidative stress. Nanoceria also increases plant growth with respect to those growing solely in mercury. Nanoceria alone does not significantly affect the growth of Vigna radiata as well as Bacillus coagulans and Escherichia coli, thereby proving its non-hazardous nature. It also significantly increases the growth of Bacillus coagulans at 25 ppm and 50 ppm of mercury. This study throws light upon the biologically non-hazardous nature of this particle by revealing how it promotes the growth of two soil bacteria Bacillus coagulans and E.coli at various dosages. The results of this study pave the way for the use of cerium oxide nanoparticles in plants and various other organisms to combat abiotic stress.

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.

Nanoceria: an innovative strategy for cancer treatment

Nanoceria or cerium oxide nanoparticles characterised by the co-existing of Ce³⁺ and Ce⁴⁺ that allows self-regenerative, redox-responsive dual-catalytic activities, have attracted interest as an innovative approach to treating cancer. Depending on surface characteristics and immediate environment, nanoceria exerts either anti- or pro-oxidative effects which regulate reactive oxygen species (ROS) levels in biological systems. Nanoceria mimics ROS-related enzymes that protect normal cells at physiological pH from oxidative stress and induce ROS production in the slightly acidic tumour microenvironment to trigger cancer cell death. Nanoceria as nanozymes also generates molecular oxygen that relieves tumour hypoxia, leading to tumour cell sensitisation to improve therapeutic outcomes of photodynamic (PDT), photothermal (PTT) and radiation (RT), targeted and chemotherapies. Nanoceria has been engineered as a nanocarrier to improve drug delivery or in combination with other drugs to produce synergistic anti-cancer effects. Despite reported preclinical successes, there are still knowledge gaps arising from the inadequate number of studies reporting findings based on physiologically relevant disease models that accurately represent the complexities of cancer. This review discusses the dual-catalytic activities of nanoceria responding to pH and oxygen tension gradient in tumour microenvironment, highlights the recent nanoceria-based platforms reported to be feasible direct and indirect anti-cancer agents with protective effects on healthy tissues, and finally addresses the challenges in clinical translation of nanoceria based therapeutics.

Role of Cerium Oxide Nanoparticles and Doxorubicin in Improving Cancer Management: A Mini Review

Cancer is one of the significant issues with public health and the second leading cause of death worldwide. The three most lethal cancers in the general population are stomach, lung, and liver cancers, in which lung and breast cancers cause the majority of cancer-associated deaths among men and women, respectively. CeO2 nanoparticles have a cytoprotectant effect in normal cells and a cytotoxic effect in cancer cells that enables them to induce the reactive oxygen species (ROS) production within cancer cells, which in turn develops reactive nitrogen species (RNS) that interfere with intracellular activities, and this property makes them an excellent anticancer agent. Because of its biofilm suppression, free radical scavenging ability, redox activity, and other unique properties, attention has been bestowed on cerium oxide nanoparticles as a potential alternative to solve many biomedical issues in the future. This review mainly focuses on the combinatorial effect of cerium dioxide nanoparticles and Doxorubicin in cancer management.

CeO2-Azacrown Conjugate as a Nanoplatform for Combined Radiopharmaceuticals

This study is one of the first attempts to assess CeO₂ nanoparticles as a nanoplatform for radiopharmaceuticals with radionuclides. The process of functionalization using a bifunctional azacrown ligand is described, and the resulting conjugates are characterized by IR and Raman spectroscopy. Their complexes with ²⁰⁷Bi show a high stability in medically relevant media, thus encouraging the further study of these conjugates in vivo as potential combined radiopharmaceuticals.

In vitro and in vivo evaluation of cerium oxide nanoparticles in respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the most common cause of viral bronchiolitis among children worldwide, yet there is no vaccine for RSV disease. This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles (CNP) to modulate reactive oxygen (ROS) and nitrogen (RNS) species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo. Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods, respectively. Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential. In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages. Specifically, cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels. Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFα and IL-12p70, while simultaneously decreasing M2 CD206 expression. Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice. Notably, cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation, avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils, which are associated with RSV-mediated inflammation. In conclusion, we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.

Engineering chitosan nano-cocktail containing iron oxide and ceria: A two-in-one approach for treatment of inflammatory diseases and tracking of material delivery

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl₄-treated C57BL/6 mice, demonstrated by a shortened T₂^⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl₄ treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl₄-treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases.

Influence of nanoparticles on the haemostatic balance: between thrombosis and haemorrhage

Maintenance of a delicate haemostatic balance or a balance between clotting and bleeding is critical to human health. Irrespective of administration route, nanoparticles can reach the bloodstream and might interrupt the haemostatic balance by interfering with one or more components of the coagulation, anticoagulation, and fibrinolytic systems, which potentially lead to thrombosis or haemorrhage. However, inadequate understanding of their effects on the haemostatic balance, along with the fact that most studies mainly focus on the functionality of nanoparticles while forgetting or leaving behind their risk to the body's haemostatic balance, is a major concern. Hence, our review aims to provide a comprehensive depiction of nanoparticle-haemostatic balance interactions, which has not yet been covered. The synergistic roles of cells and plasma factors participating in haemostatic balance are presented. Possible interactions and interference of each type of nanoparticle with the haemostatic balance are comprehensively discussed, particularly focusing on the underlying mechanisms. Interactions of nanoparticles with innate immunity potentially linked to haemostasis are mentioned. Various physicochemical characteristics that influence the nanoparticle-haemostatic balance are detailed. Challenges and future directions are also proposed. This insight would be valuable for the establishment of nanoparticles that can either avoid unintended interference with the haemostatic balance or purposely downregulate/upregulate its key components in a controlled manner.