Antioxidant Enzyme-Mimetic Activity and Neuroprotective Effects of Cerium Oxide Nanoparticles Stabilized with Various Ratios of Citric Acid and EDTA

Multifunctional cerium nanolabels in electrochemical immunosensing with improved robustness and performance: determination of TIM-1 in colorectal cancer scenarios as a case study

A multifunctional cerium oxide nanoparticles (CeO2NPs)-based nanolabel is exploited to implement an electrochemical sandwich-type immunoplatform for the determination of T-cell immunoglobulin and mucin domain 1 (TIM-1) biomarker, a mucin-like class I membrane glycoprotein associated with cancer angiogenesis. The immunoplatform is constructed using screen-printed electrodes where capture antibody is immobilized through the chemistry of diazonium salts. CeO2NPs exhibit robust pseudo-peroxidase activity even at high substrate concentrations. They are covalently functionalized in a simple manner after carboxylation with a detector antibody (dAb), acting dually as a nanozyme and nanocarrier for sensing bioreceptors. This allows the development of immunoplatforms with improved robustness and performance (in terms of a moderate enhancement in sensitivity, a significant expansion in the linear range, and a reduction in the background current) compared with the immunoplatforms prepared using nanolabels also decorated with the natural enzyme (horseradish peroxidase, HRP) or the conventional enzymatic labeling involving the dAb and an HRP-secondary antibody. Under the optimized experimental conditions, the developed electrochemical immunoplatform allows the highly sensitive detection of the TIM-1 glycoprotein, with a detection limit of 9.9 pg mL-1 and a linear working range of 33-600 pg mL-1. This performance permits biomarker quantification within clinically relevant ranges. This innovative configuration enables the precise diagnosis and stratification of colorectal cancer patients by analyzing plasma samples without pretreatment beyond a sample dilution and allows establishment of the first cut-off values reported for this purpose.

Gualou Guizhi Granule inhibits microglia-mediated neuroinflammation to protect against neuronal apoptosis in vitro and in vivo

Object

Neuroinflammation mediated by microglia has emerged as a critical factor in ischemic stroke and neuronal damage. Gualou Guizhi Granule (GLGZG) has been shown to suppress inflammation in lipopolysaccharide (LPS)-activated microglia, though the underlying mechanisms and its protective effects against neuronal apoptosis remain unclear. This study aims to investigate how GLGZG regulates the Notch signaling pathway in microglia to reduce neuroinflammation and protect neurons from apoptosis.

Method

Using in vitro and in vivo models, we explored GLGZG's impact on microglia activation, pro-inflammatory cytokines, and neuronal apoptosis. Microglial cells were activated with LPS, and primary neuronal cells were exposed to LPS-activated microglia to simulate neuroinflammation. Additionally, we investigated the effects of GLGZG in combination with N-[N-[3,5-difluorophenacetyl]-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) or siRNA-Notch1 to further elucidate the involvement of the Notch signaling pathway.

Results

GLGZG significantly inhibited microglia activation and reduced neuroinflammation by de-creasing the levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α in both in vitro and in vivo models. GLGZG also effectively protected against microglia-induced neuronal apoptosis. Mechanistically, GLGZG down-regulated key components of the Notch signaling pathway, in-cluding Notch-1, NICD, RBPSUH, and Hes-1, in activated microglia. Combined treatment with GLGZG and DAPT or siRNA-Notch1 demonstrated enhanced inhibition of microglial activation and neuroinflammation.

Conclusion

Our findings reveal that GLGZG exerts its protective effects through the suppression of the Notch signaling pathway, thereby inhibiting microglia activation, reducing neuroinflammation, and safeguarding neurons from neuroinflammation-induced damage, offering potential as a therapeutic agent for ischemic stroke-induced neuroinflammation.

Targeting Reactive Oxygen Species for Diagnosis of Various Diseases

Reactive oxygen species (ROS) are generated predominantly during cellular respiration and play a significant role in signaling within the cell and between cells. However, excessive accumulation of ROS can lead to cellular dysfunction, disease progression, and apoptosis that can lead to organ dysfunction. To overcome the short half-life of ROS and the relatively small amount produced, various imaging methods have been developed, using both endogenous and exogenous means to monitor ROS in disease settings. In this review, we discuss the molecular mechanisms underlying ROS production and explore the methods and materials that could be used to detect ROS overproduction, including iron-based materials, ROS-responsive chemical bond containing polymers, and ROS-responsive molecule containing biomaterials. We also discuss various imaging and imaging techniques that could be used to target and detect ROS overproduction. We discuss the ROS imaging potentials of established clinical imaging methods, such as magnetic resonance imaging (MRI), sonographic imaging, and fluorescence imaging. ROS imaging potentials of other imaging methods, such as photoacoustic imaging (PAI) and Raman imaging (RI) that are currently in preclinical stage are also discussed. Finally, this paper focuses on various diseases that are associated with ROS overproduction, and the current and the future clinical applications of ROS-targeted imaging. While the most widely used clinical condition is cardiovascular diseases, its potential extends into non-cardiovascular clinical conditions, such as neurovascular, neurodegenerative, and other ROS-associated conditions, such as cancers, skin aging, acute kidney injury, and inflammatory arthritis.

Cerium oxide nanoparticles (nanoceria) pretreatment attenuates cell death in the hippocampus and cognitive dysfunction due to repeated isoflurane anesthesia in newborn rats

General anesthetics exposure, particularly prolonged or repeated exposure, is a crucial cause of neurological injuries. Notably, isoflurane (ISO), used in pediatric anesthesia practice, is toxic to the developing brain. The relatively weak antioxidant system at early ages needs antioxidant support to protect the brain against anesthesia. Cerium oxide nanoparticles (CeO2-NPs, nanoceria) are nano-antioxidants and stand out due to their unique surface chemistry, high stability, and biocompatibility. Although CeO2-NPs have been shown to exhibit neuroprotective and cognitive function-facilitating effects, there are no reports on their protective effects against anesthesia-induced neurotoxicity and cognitive impairments. Herein, Wistar albino rat pups were exposed to ISO (1.5 %, 3-h) at postnatal day (P)7+P9+P11, and the protective properties of CeO2-NP pretreatment (0.5 mg/kg, intraperitoneal route) were investigated for the first time. The control group at P7+9+11 received 50 % O2 (3-h) instead of ISO. Exposure to nanoceria one-hour before ISO protected hippocampal neurons of the developing rat brain against apoptosis [determined by hematoxylin-eosin (HE) staining, immunohistochemistry (IHC) analysis with caspase-3, and immunoblotting with Bax/Bcl2, cleaved caspase-3 and PARP1] oxidative stress, and inflammation [determined by immunoblotting with 4-hydroxynonenal (4HNE), nuclear factor kappa-B (NF-κB), and tumor necrosis factor-alpha (TNF-α)]. CeO2-NP pretreatment also reduced ISO-induced learning (at P28-32) and memory (at P33) deficits evaluated by Morris Water Maze. However, memory deficits and thigmotactic behaviors were detected in the agent-control group; elimination of these harmful effects will be possible with dose studies, thus providing evidence supporting safer use. Overall, our findings support pretreatment with nanoceria application as a simple strategy that might be used for pediatric anesthesia practice to protect infants and children from ISO-induced cell death and learning and memory deficits.

Novel Pyrroloquinoline Quinone-Modified Cerium Oxide Nanoparticles and Their Selective Cytotoxicity Under X-Ray Irradiation

Ionizing radiation leads to the development of oxidative stress and damage to biologically important macromolecules (DNA, mitochondria, etc.), which in turn lead to cell death. In the case of radiotherapy, both cancer cells and normal cells are damaged. In this regard, the development of new selective antioxidants is relevant. In this study, we first investigated the redox activity of cerium oxide-pyrroloquinoline quinone nanoparticles (CeO2@PQQ NPs) and their cytotoxic effects on normal (mouse fibroblasts, L929) and cancer (mouse adenocarcinoma, EMT6/P) cell cultures. Furthermore, the biological activity of CeO2@PQQ NPs was evaluated in comparison with that of CeO2 NPs and PQQ. The nanoparticles demonstrated pH-dependent reductions in the content of hydrogen peroxide after X-ray exposure. Our findings indicate that viability of EMT6/P cells was more adversely affected by CeO2@PQQ NPs at lower concentrations (0.1 μM) compared to L929. Following X-ray irradiation at a dose of 5 Gy, significant changes in mitochondrial potential (by 29%) and decreased glutathione levels (by 32%) were also observed in EMT6/P culture following irradiation and incubation with CeO2@PQQ NPs. Furthermore, EMT6/P exhibited a 2.5-fold increase in micronuclei and a 2-fold reduction in survival fraction compared to L929. It is hypothesized that CeO2@PQQ NPs may exhibit selective cytotoxicity and radiosensitizing properties against EMT6/P cancer cells. The findings suggest that CeO2@PQQ NPs may have potential as a selective redox-active antioxidant/pro-oxidant in response to X-ray radiation.

The Role of Mitochondrial Homeostasis in Mesenchymal Stem Cell Therapy-Potential Implications in the Treatment of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a hereditary disorder characterized by bones that are fragile and prone to breaking. The efficacy of existing therapies for OI is limited, and they are associated with potentially harmful side effects. OI is primarily due to a mutation of collagen type I and hence impairs bone regeneration. Mesenchymal stem cell (MSC) therapy is an attractive strategy to take advantage of the potential benefits of these multipotent stem cells to address the underlying molecular defects of OI by differentiating osteoblasts, paracrine effects, or immunomodulation. The maintenance of mitochondrial homeostasis is an essential component for improving the curative efficacy of MSCs in OI by affecting the differentiation, signaling, and immunomodulatory functions of MSCs. In this review, we highlight the MSC-based therapy pathway in OI and introduce the MSC regulation mechanism by mitochondrial homeostasis. Strategies aiming to modulate the metabolism and reduce the oxidative stress, as well as innovative strategies based on the use of compounds (resveratrol, NAD+, α-KG), antioxidants, and nanomaterials, are analyzed. These findings may enable the development of new strategies for the treatment of OI, ultimately resulting in improved patient outcomes.

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.

Surface-Tailored Nanoplatform for the Diagnosis and Management of Stroke: Current Strategies and Future Outlook

Stroke accounts for one of the top leading reasons for neurological mortality and morbidity around the globe. Both ischemic and hemorrhagic strokes lead to local hypoxia and are brought about by the occlusion or rupturing of the blood vessels. The events taking place after the onset of a stroke include membrane ion pump failure, calcium and glutamate-mediated excitotoxicity, increased ROS production causing DNA damage, mitochondrial dysfunction, oxidative stress, development of brain edema, and microvascular dysfunction. To date, tissue plasminogen activator (tPA) therapy and mechanical removal of blood clots are the only clinically available stroke therapies, approved by Food and Drug Administration (FDA). But because of the narrow therapeutic window of around 4.5 h for tPA therapy and complications like systemic bleeding and anaphylaxis, more clinical trials are ongoing in the same field. Therefore, using nanocarriers with diverse physicochemical properties is a promising strategy in treating and diagnosing stroke as they can efficiently bypass the tight blood-brain barrier (BBB) through mechanisms like receptor-mediated transcytosis and help achieve controlled and targeted drug delivery. In this review, we will mainly focus on the pathophysiology of stroke, BBB alterations following stroke, strategies to target BBB for stroke therapies, different types of nanocarriers currently being used for therapeutic intervention of stroke, and biomarkers as well as imaging techniques used for the detection and diagnosis of stroke.

Nanodrugs for the Treatment of Ischemic Stroke: A Systematic Review

Ischemic stroke, a significant neurovascular disorder, currently lacks effective restorative medication. However, recently developed nanomedicines bring renewed promise for alleviating ischemia's effects and facilitating the healing of neurological and physical functions. The aim of this systematic review was to evaluate the efficacy of nanotherapies in animal models of stroke and their potential impact on future stroke therapies. We also assessed the scientific quality of current research focused on nanoparticle-based treatments for ischemic stroke in animal models. We summarized the effectiveness of nanotherapies in these models, considering multiple factors such as their anti-inflammatory, antioxidant, and angiogenetic properties, as well as their safety and biodistribution. We conclude that the application of nanomedicines may reduce infarct size and improve neurological function post-stroke without causing significant organ toxicity.

CeO2 nanoparticles improve prooxidant/antioxidant balance, life quality and survival of old male rats

Due to its unique redox chemistry, nanoceria is considered as potent free radical scavenger and antioxidant. However, their protective capacity in aging organisms remains controversial. To detect the anti-aging effects associated with the redox activity of 2 and 10 nm nano-CeO2, different test systems were used, including in vitro analysis, in situ assay of mitochondria function and in vivo studies of suitable nano-CeO₂ on aging of male Wistar rats from 22 months-old to the end of life. The 2 nm nanoparticles exhibited not only antioxidant (^·OH scavenging; chemiluminescence assay; decomposition of H₂O₂, phosphatidylcholine autooxidation) but also prooxidant properties (reduced glutathione and reduced nicotinamide adenine dinucleotide phosphate oxidation) as well as affected mitochondria whereas in most test systems 10 nm nano-CeO₂ showed less activity or was inert. Prolonged use of the more redox active 2 nm nano-CeO₂ (0.25-0.3 mg/kg/day) in vivo with drinking water resulted in improvement in physiological parameters and normalization of the prooxidant/antioxidant balance in liver and blood of aging animals. Survival analysis using Kaplan-Meier curve and Gehan tests with Yates' correction showed that by the time the prooxidant-antioxidant balance was assessed (32 months), survival rates exceeded the control values most considerably. The apparent median survival for the control rats was 900 days, and for the experimental rats-960 days. In general, the data obtained indicate the ability of extra-small 2 nm nano-CeO2 to improve quality of life and increase the survival rate of an aging organism.

Research Progress on Nutritional Value, Preservation and Processing of Fish-A Review

The global population has rapidly expanded in the last few decades and is continuing to increase at a rapid pace. To meet this growing food demand fish is considered a balanced food source due to their high nutritious value and low cost. Fish are rich in well-balanced nutrients, a good source of polyunsaturated fatty acids and impose various health benefits. Furthermore, the most commonly used preservation technologies including cooling, freezing, super-chilling and chemical preservatives are discussed, which could prolong the shelf life. Non-thermal technologies such as pulsed electric field (PEF), fluorescence spectroscopy, hyperspectral imaging technique (HSI) and high-pressure processing (HPP) are used over thermal techniques in marine food industries for processing of most economical fish products in such a way as to meet consumer demands with minimal quality damage. Many by-products are produced as a result of processing techniques, which have caused serious environmental pollution. Therefore, highly advanced technologies to utilize these by-products for high-value-added product preparation for various applications are required. This review provides updated information on the nutritional value of fish, focusing on their preservation technologies to inhibit spoilage, improve shelf life, retard microbial and oxidative degradation while extending the new applications of non-thermal technologies, as well as reconsidering the values of by-products to obtain bioactive compounds that can be used as functional ingredients in pharmaceutical, cosmetics and food processing industries.

Efficacy of Green Cerium Oxide Nanoparticles for Potential Therapeutic Applications: Circumstantial Insight on Mechanistic Aspects

Green synthesized cerium oxide nanoparticles (GS-CeO₂ NPs) have a unique size, shape, and biofunctional properties and are decorated with potential biocompatible agents to perform various therapeutic actions, such as antimicrobial, anticancer, antidiabetic, and antioxidant effects and drug delivery, by acquiring various mechanistic approaches at the molecular level. In this review article, we provide a detailed overview of some of these critical mechanisms, including DNA fragmentation, disruption of the electron transport chain, degradation of chromosomal assemblage, mitochondrial damage, inhibition of ATP synthase activity, inhibition of enzyme catalytic sites, disorganization, disruption, and lipid peroxidation of the cell membrane, and inhibition of various cellular pathways. This review article also provides up-to-date information about the future applications of GS-CeONPs to make breakthroughs in medical sectors for the advancement and precision of medicine and to effectively inform the disease diagnosis and treatment strategies.

Central nervous system injury meets nanoceria: opportunities and challenges

Central nervous system (CNS) injury, induced by ischemic/hemorrhagic or traumatic damage, is one of the most common causes of death and long-term disability worldwide. Reactive oxygen and nitrogen species (RONS) resulting in oxidative/nitrosative stress play a critical role in the pathological cascade of molecular events after CNS injury. Therefore, by targeting RONS, antioxidant therapies have been intensively explored in previous studies. However, traditional antioxidants have achieved limited success thus far, and the development of new antioxidants to achieve highly effective RONS modulation in CNS injury still remains a great challenge. With the rapid development of nanotechnology, novel nanomaterials provided promising opportunities to address this challenge. Within these, nanoceria has gained much attention due to its regenerative and excellent RONS elimination capability. To promote its practical application, it is important to know what has been done and what has yet to be done. This review aims to present the opportunities and challenges of nanoceria in treating CNS injury. The physicochemical properties of nanoceria and its interaction with RONS are described. The applications of nanoceria for stroke and neurotrauma treatment are summarized. The possible directions for future application of nanoceria in CNS injury treatment are proposed.

Constructing virus-like SiOx/CeO2/VOx nanozymes for 1064 nm light-triggered mild-temperature photothermal therapy and nanozyme catalytic therapy

The construction of nanoplatforms with combined photothermal properties and cascading enzymatic activities has become an active area of anticancer research. However, the overheating of photothermal therapy (PTT) and the specific properties of tumor microenvironment (TME) greatly impaired the therapeutic efficiency. Herein, we rationally fabricated a virus-like SiO_x/CeO₂/VO_x (SCV) nanoplatform for 1064 nm near-infrared (NIR) triggered mild-temperature PTT and nanozyme catalytic therapy. Firstly, the virus-like shape of SiO_x/CeO₂/VO_x made it favorable for cell adhesion and improved its phagocytosis in cells, and the SCV generated an effective PTT effect upon 1064 nm laser irradiation. Particularly, the produced VO²⁺ in TME could be used as a heat shock protein inhibitor to inhibit the expression of heat shock protein 60 (HSP60) to enhance the PTT efficiency. Moreover, the SCV nanozyme exhibited obvious peroxidase-mimic (POD) catalytic activity, which could generate highly toxic free radical ions (˙OH) under acidic conditions. The mild-temperature heat and ˙OH produced by enzymatic catalysis effectively blocked the tumor growth, as verified firmly by in vitro and in vivo tests. Our designed virus-like SCV nanozyme with POD mimic enzyme activity and a mild photothermal effect may provide a new way of thinking about the combination therapy model.

Anticancer Therapeutic Effects of Cerium Oxide Nanoparticles: Known and Unknown Molecular Mechanisms

Cerium-based nanoparticles (CeNPs), particularly cerium oxide (CeO2), have been studied extensively for their antioxidant and prooxidant properties. However, their complete redox and enzyme-mimetic mechanisms of therapeutic action at the molecular...

Dodging blood brain barrier with "nano" warriors: Novel strategy against ischemic stroke

Ischemic stroke (IS) is one of the leading causes of death and disability resulting in inevitable burden globally. Ischemic injury initiates cascade of pathological events comprising energy dwindling, failure of ionic gradients, failure of blood brain barrier (BBB), vasogenic edema, calcium over accumulation, excitotoxicity, increased oxidative stress, mitochondrial dysfunction, inflammation and eventually cell death. In spite of such complexity of the disease, the only treatment approved by US Food and Drug Administration (FDA) is tissue plasminogen activator (t-PA). This therapy overcome blood deficiency in the brain along with side effects of reperfusion which are responsible for considerable tissue injury. Therefore, there is urgent need of novel therapeutic perspectives that can protect the integrity of BBB and salvageable brain tissue. Advancement in nanomedicine is empowering new approaches that are potent to improve the understanding and treatment of the IS. Herein, we focus nanomaterial mediated drug delivery systems (DDSs) and their role to bypass and cross BBB especially via intranasal drug delivery. The various nanocarriers used in DDSs are also discussed. In a nut shell, the objective is to provide an overview of use of nanomedicine in the diagnosis and treatment of IS to facilitate the research from benchtop to bedside.

Redox Active Cerium Oxide Nanoparticles: Current Status and Burning Issues

Research on cerium oxide nanoparticles (nanoceria) has captivated the scientific community due to their unique physical and chemical properties, such as redox activity and oxygen buffering capacity, which made them available for many technical applications, including biomedical applications. The redox mimetic antioxidant properties of nanoceria have been effective in the treatment of many diseases caused by reactive oxygen species (ROS) and reactive nitrogen species. The mechanism of ROS scavenging activity of nanoceria is still elusive, and its redox activity is controversial due to mixed reports in the literature showing pro-oxidant and antioxidant activity. In light of its current research interest, it is critical to understand the behavior of nanoceria in the biological environment and provide answers to some of the critical and open issues. This review critically analyzes the status of research on the application of nanoceria to treat diseases caused by ROS. It reviews the proposed mechanism of action and shows the effect of surface coatings on its redox activity. It also discusses some of the crucial issues in deciphering the mechanism and redox activity of nanoceria and suggests areas of future research.

Nanoceria, the versatile nanoparticles: Promising biomedical applications

Nanotechnology has been a boon for the biomedical field due to the freedom it provides for tailoring of pharmacokinetic properties of different drug molecules. Nanomedicine is the medical application of nanotechnology for the diagnosis, treatment and/or management of the diseases. Cerium oxide nanoparticles (CNPs) are metal oxide-based nanoparticles (NPs) which possess outstanding reactive oxygen species (ROS) scavenging activities primarily due to the availability of "oxidation switch" on their surface. These NP have been found to protect from a number of disorders with a background of oxidative stress such as cancer, diabetes etc. In fact, the CNPs have been found to possess the environment-dependent ROS modulating properties. In addition, the inherent catalase, SOD, oxidase, peroxidase and phosphatase mimetic properties of CNPs provide them superiority over a number of NPs. Further, chemical reactivity of CNPs seems to be a function of their surface chemistry which can be precisely tuned by defect engineering. However, the contradictory reports make it necessary to critically evaluate the potential of CNPs, in the light of available literature. The review is aimed at probing the feasibility of CNPs to push towards the clinical studies. Further, we have also covered and censoriously discussed the suspected negative impacts of CNPs before making our way to a consensus. This review aims to be a comprehensive, authoritative, critical, and accessible review of general interest to the scientific community.

Polyoxometalate-Mediated Vacancy-Engineered Cerium Oxide Nanoparticles Exhibiting Controlled Biological Enzyme-Mimicking Activities

The biological enzyme-mimetic activity of cerium oxide nanoparticles (CeNPs) is well known to scavenge the reactive oxygen and nitrogen species in cell culture and animal models, imparting protection from the deleterious effects of oxidative and nitrosative stress. The superoxide dismutase (SOD)- and catalase-mimicking activity of CeNPs is reported to be controlled by the oxidation state of the surface "Ce" ions, where a high ratio of Ce^3+/4+ or Ce^4+/3+ has been considered for the displayed SOD and catalase-like activity, respectively. However, the redox behavior of CeNPs can be controlled by certain ligands that could offer changes in their enzyme-mimetic properties. Therefore, in this work, we have studied the enzyme-mimetic activities of CeNPs under the influence of polyoxometalates [phosphomolybdic acid (PMA) and phosphotungstic acid (PTA)], which are electron-dense molecules displaying quick and reversible multielectron redox reactions. Results revealed that the interaction of PMA with CeNPs results in the inhibition of the SOD-like activity; however, it has no impact on the catalase-like activity. Contrary to this, the interaction of PTA with CeNPs improved the SOD as well as catalase-like activities of CeNPs (3+), which generally do not exhibit catalase activity in the bare form. Although CeNPs (3+) did not show any peroxidase-like activity, CeNPs (4+) showed excellent activity, which was enhanced after the interaction with polyoxometalates. Further, the autoregeneration ability of CeNPs was found to be intact even after PTA or PMA interaction; however, the full catalytic activity was observed in the case of PTA but partially with PMA.

Ischemia Reperfusion Injury: Opportunities for Nanoparticles

Ischemia reperfusion (IR)-induced oxidative stress, accompanied by inflammatory responses, contributes to morbidity and mortality in numerous diseases such as acute coronary syndrome, stroke, organ transplantation, and limb injury. Ischemia results in profound hypoxia and tissue dysfunction, whereas subsequent reperfusion further aggravates ischemic tissue damage through inducing cell death and activating inflammatory responses. In this review, we highlight recent studies of therapeutic strategies against IR injury. Furthermore, nanotechnology offers significant improvements in this area. Hence, we also review recent advances in nanomedicines for IR therapy, suggesting them as potent and promising strategies to improve drug delivery to IR-injured tissues and achieve protective effects.

Cerium Oxide Nanoparticles (Nanoceria): Hopes in Soft Tissue Engineering

Several biocompatible materials have been applied for managing soft tissue lesions; cerium oxide nanoparticles (CNPs, or nanoceria) are among the most promising candidates due to their outstanding properties, including antioxidant, anti-inflammatory, antibacterial, and angiogenic activities. Much attention should be paid to the physical properties of nanoceria, since most of its biological characteristics are directly determined by some of these relevant parameters, including the particle size and shape. Nanoceria, either in bare or functionalized forms, showed the excellent capability of accelerating the healing process of both acute and chronic wounds. The skin, heart, nervous system, and ophthalmic tissues are the main targets of nanoceria-based therapies, and the other soft tissues may also be evaluated in upcoming experimental studies. For the repair and regeneration of soft tissue damage and defects, nanoceria-incorporated film, hydrogel, and nanofibrous scaffolds have been proven to be highly suitable replacements with satisfactory outcomes. Still, some concerns have remained regarding the long-term effects of nanoceria administration for human tissues and organs, such as its clearance from the vital organs. Moreover, looking at the future, it seems necessary to design and develop three-dimensional (3D) printed scaffolds containing nanoceria for possible use in the concepts of personalized medicine.

The Advances of Ceria Nanoparticles for Biomedical Applications in Orthopaedics

The ongoing biomedical nanotechnology has intrigued increasingly intense interests in cerium oxide nanoparticles, ceria nanoparticles or nano-ceria (CeO2-NPs). Their remarkable vacancy-oxygen defect (VO) facilitates the redox process and catalytic activity. The verification has illustrated that CeO2-NPs, a nanozyme based on inorganic nanoparticles, can achieve the anti-inflammatory effect, cancer resistance, and angiogenesis. Also, they can well complement other materials in tissue engineering (TE). Pertinent to the properties of CeO2-NPs and the pragmatic biosynthesis methods, this review will emphasize the recent application of CeO2-NPs to orthopedic biomedicine, in particular, the bone tissue engineering (BTE). The presentation, assessment, and outlook of the orthopedic potential and shortcomings of CeO2-NPs in this review expect to provide reference values for the future research and development of therapeutic agents based on CeO2-NPs.

Cerium Oxide Nanoparticles: Recent Advances in Tissue Engineering

Submicron biomaterials have recently been found with a wide range of applications for biomedical purposes, mostly due to a considerable decrement in size and an increment in surface area. There have been several attempts to use innovative nanoscale biomaterials for tissue repair and tissue regeneration. One of the most significant metal oxide nanoparticles (NPs), with numerous potential uses in future medicine, is engineered cerium oxide (CeO2) nanoparticles (CeONPs), also known as nanoceria. Although many advancements have been reported so far, nanotoxicological studies suggest that the nanomaterial's characteristics lie behind its potential toxicity. Particularly, physicochemical properties can explain the positive and negative interactions between CeONPs and biosystems at molecular levels. This review represents recent advances of CeONPs in biomedical engineering, with a special focus on tissue engineering and regenerative medicine. In addition, a summary report of the toxicity evidence on CeONPs with a view toward their biomedical applications and physicochemical properties is presented. Considering the critical role of nanoengineering in the manipulation and optimization of CeONPs, it is expected that this class of nanoengineered biomaterials plays a promising role in the future of tissue engineering and regenerative medicine.

Efficacy of A Novel Smart Polymeric Nanodrug in the Treatment of Experimental Wounds in Rats

High-quality and aesthetic wound healing, as well as effective medical support of this process, continue to be relevant. This study aims to evaluate the medical efficacy of a novel smart polymeric nanodrug (SPN) on the rate and mechanism of wound healing in experimental animals. The study was carried out in male Wistar rats (aged 8-9 months). In these animals, identical square wounds down to the fascia were made in non-sterile conditions on the back on both sides of the vertebra. SPN was used for the treatment of one wound, and the other wound was left without treatment (control group). Biocompatible citrate-stabilized cerium oxide nanoparticles integrated into a polysaccharide hydrogel matrix containing natural and synthetic polysaccharide polymers (pectin, alginate, chitosan, agar-agar, water-soluble cellulose derivatives) were used as the therapeutic agent. Changes in the wound sizes (area, volume) over time and wound temperature were assessed on Days 0, 1, 3, 5, 7, and 14. Histological examination of the wounds was performed on Days 3, 7, and 14. The study showed that the use of SPN accelerated wound healing in comparison with control wounds by inhibiting the inflammatory response, which was measured by a decreased number of white blood cells in SPN-treated wounds. It also accelerated the development of fibroblasts, with an early onset of new collagen synthesis, which eventually led to the formation of more tender postoperative scars. Thus, the study demonstrated that the use of SPN for the treatment of wounds was effective and promising.

Variable in Vivo and in Vitro Biological Effects of Cerium Oxide Nanoparticle Formulations

Cerium oxide nanoparticles (CeNPs) exhibit redox capacity in vitro with efficacy in in vivo disease models of oxidative stress. Here we compare, in parallel, three CeNP formulations with distinct chemical stabilizers and size. In vitro assays revealed antioxidant activity from all the CeNPs, but when administered to mice with a reactive oxygen species (ROS) mediated model of multiple sclerosis, only custom-synthesized Cerion NRx (CNRx) citrate-EDTA stabilized CeNPs provided protection against disease. Detectable levels of ceria and reduced ROS levels in the brains of CNRx CeNP-treated mice imply that these CeNPs' unique properties influence tissue distribution and subsequent biological activity, suggesting why differing CeNP formulations yield different in vivo effects in various models. Further, the variation in in vivo vs in vitro results with these CeNP formulations highlights the necessity for in vivo studies that confirm whether the inherent catalytic activity of CeNPs is maintained after transport and distribution within intact biological systems.