Combined effect of Cerium oxide nanoparticles loaded scaffold and photobiomodulation therapy on pain and neuronal regeneration following spinal cord injury: an experimental study.

BACKGROUND: Spinal cord injury (SCI) remained one of the challenges to treat due to its complicated mechanisms. Photobiomodulation therapy (PBMT) accelerates neuronal regeneration. Cerium oxide nanoparticles (CeONPs) also eliminate free radicals in the environment. The present study aims to introduce a combined treatment method of making PCL scaffolds as microenvironments, seeded with CeONPs and the PBMT technique for SCI treatment. METHODS: The surgical hemi-section was used to induce SCI. Immediately after the SCI induction, the scaffold (Sc) was loaded with CeONPs implanted. PBMT began 30 min after SCI induction and lasted for up to 4 weeks. Fifty-six male rats were randomly divided into seven groups. Glial fibrillary acidic protein (GFAP) (an astrocyte marker), Connexin 43 (Con43) (a member of the gap junction), and gap junctions (GJ) (a marker for the transfer of ions and small molecules) expressions were evaluated. The behavioral evaluation was performed by BBB, Acetone, Von Frey, and radiant heat tests. RESULT: The SC + Nano + PBMT group exhibited the most remarkable recovery outcomes. Thermal hyperalgesia responses were mitigated, with the combined approach displaying the most effective relief. Mechanical allodynia and cold allodynia responses were also attenuated by treatments, demonstrating potential pain management benefits. CONCLUSION: These findings highlight the potential of PBMT, combined with CeONPs-loaded scaffolds, in promoting functional motor recovery and alleviating pain-related responses following SCI. The study underscores the intricate interplay between various interventions and their cumulative effects, informing future research directions for enhancing neural repair and pain management strategies in SCI contexts.

Solanum tuberosum tuber-driven starch-mediated green-hydrothermal synthesis of cerium oxide nanoparticles for efficient photocatalysis and antimicrobial activities.

In this study, we are reporting for the first time the utilization of Solanum tuberosum tuber-driven, starch-mediated, green-hydrothermally synthesized cerium oxide nanoparticles (G-CeO2 NPs) for the antibacterial activity and photodegradation of cationic (methylene blue, MB) and anionic (methyl orange, MO) dyes separately and in combination, aimed at environmental remediation. The XRD analysis confirms the fluorite structure of G-CeO2 NPs, displaying an average crystallite size of 9.6 nm. Further, XPS confirms the existence of 24% of Ce3+ oxidation states within G-CeO2 NPs. Morphological studies through FE-SEM and TEM reveal that starch-driven OH- ion production leads to a high percentage of active crystal facets, favoring the formation of Ce3+-rich CeO2 NPs. Photocatalytic experiments conducted under UV-A illumination demonstrate the superior degradation performance of G-CeO2 NPs, with MB degradation reaching 93.4% and MO degradation at 77.2% within 90 min. This outstanding catalytic activity is attributed to the mesoporous structure (pore diameter of 5.63 nm) with a narrow band gap, a large surface area (103.38 m2g-1), and reduced charge recombination, as validated by BET, UV-visible, and electrochemical investigations. The identification of photogenerated intermediates is achieved through LCMS, while the mineralization is monitored via total organic carbon analysis. Moreover, the scavenging experiments point towards the involvement of reactive oxygen species in organic oxidation, demonstrating efficiency over five consecutive trials. Additionally, G-CeO2 NPs exhibit potent antibacterial activity against both gram-positive and gram-negative bacteria. This study presents an innovative, and efficient approach to environmental remediation, shedding light on the potential of G-CeO2 NPs in addressing environmental pollution challenges.

Tailoring the Structural and Optical Properties of Cerium Oxide Nanoparticles Prepared by an Ecofriendly Green Route Using Plant Extracts.

The present study explores an environmentally friendly green approach to obtain cerium oxide nanoparticles via a biomediated route using Mellisa officinalis and Hypericum perforatum plant extracts as reducing agents. The as-prepared nanoparticles were studied for their structural and morphological characteristics using XRD diffractometry, scanning electron microscopy, Raman, fluorescence and electronic absorption spectra, and X-ray photoelectron spectroscopy (XPS). The XRD pattern has shown the centered fluorite crystal structure of cerium oxide nanoparticles with average crystallite size below 10 nm. These observations were in agreement with the STEM data. The cubic fluorite structure of the cerium oxide nanoparticles was confirmed by the vibrational mode around 462 cm-1 due to the Ce-08 unit. The optical band gap was estimated from UV-Vis reflectance spectra, which was found to decrease from 3.24 eV to 2.98 eV. A higher specific area was determined for the sample using M. officinalis aqueous extract. The EDX data indicated that only cerium and oxygen are present in the green synthesized nanoparticles.

Mechanistic understanding of green synthesized cerium nanoparticles for the photocatalytic degradation of dyes and antibiotics from aqueous media and antimicrobial efficacy: A review.

In recent years, extensive research endeavors are being undertaken for synthesis of an efficient, economic and eco-friendly cerium oxide nanoparticles (CeO2 NPs) using plant extract mediated greener approach. A number of medicinal plants and their specific parts (flowers, bark, seeds, fruits, seeds and leaves) have been found to be capable of synthesizing CeO2 NPs. The specific key phytochemical constituents of plants such as alkaloids, terpenoids, phenolic acids, flavones and tannins can play significant role as a reducing, stabilizing and capping agents in the synthesis of CeO2 NPs from their respective precursor solution of metal ions. The CeO2 NPs are frequently using in diverse fields of science and technology including photocatalytic degradation of dyes, antibiotics as well as antimicrobial applications. In this review, the mechanism behind the green synthesis CeO2 NPs using plant entities are summarized along with discussion of analytical results from characterization techniques. An overview of CeO2 NPs for water remediation application via photocatalytic degradation of dyes and antibiotics are discussed. In addition, the mechanisms of antimicrobial efficacy of CeO2 NPs and current challenges for their sustainable application at large scale in real environmental conditions are discussed.

N-Acetyl cysteine amide and cerium oxide nanoparticles as a drug delivery for ischemic stroke treatment: Inflammation and oxidative stress crosstalk.

BACKGROUND: Inflammation and oxidative stress crosstalk is involved in the ischemic stroke(IS) pathogenesis and the new therapeutic options should be offered based on the targets that are critical in the golden hour of IS. YKL-40 and total antioxidant capacity(TAC), the inflammation and oxidative stress biomarkers, provide us with clues for proper intervention targets. N-acetyl cysteine amide (NACA), a lipophilic antioxidant, with a nanoparticle-based drug delivery system is permeable enough to penetrate blood-brain barrier (BBB) and was proposed as a new treatment option for IS. In this study, we evaluated the YKL-40 and TAC levels in the sera of IS patients to elucidate the best intervention target. A rat tissue model is used to assess the NACA efficiency. The microbiology tests performed to figure out the potential NACA and antibiotics interactions. MATERIAL AND METHODS: The YKL-40 and TAC were measured in the serum of IS patients by ELISA and FRAP methods, respectively. The serum samples were obtained 12 h after the patient's admission and meantime other laboratory findings and NIHSS-based prognosis were recorded. In the animal study, the brain cortex, liver, kidney, adipose, and the heart of healthy rats were dissected and then incubated in DMEM cell culture media containing 50 micrograms/milliliter of nanoparticles; the nanoparticles were titanium dioxide nanoparticles (TiO2 NPs), copper oxide nanoparticles (CuO NPs) and cerium dioxide nanoparticles (CeO2 NPs). Olive oil and human serum albumin solution were exposed to the nanoparticles with and without NACA. TAC was measured in the supernatant culture media. With similar concentrations and settings, we evaluated the NACA, nanoparticle, and antibiotics interactions on pseudomonas aeruginosa. RESULTS: There was a nonparametric correlation between YKL-40 levels and post stroke serum TAC levels. Nonsmokers had higher YKL-40 and TAC levels than smokers. A new calculated variable, urea*lymphocyte/age, predicts a poor prognosis with an acceptable AUC (0.708). Exposing to the nanoparticles, the liver, kidney, and brain had a significantly higher TAC than adipose and cardiac tissue. The NACA had an ameliorative effect against TiO2 NPs in the brain. This effectiveness of NACA was also observed against CuO NPs treatment. However, the CeO2 NPs exert a strong antioxidant property by reducing the TAC in the brain tissue but not the others. Albumin showed antioxidant properties by itself, but olive oil had an inert behavior. NACA had no interaction with the action of routine antibiotics. CONCLUSION: Oxidative stress but not inflammation is the best point for intervention in IS patients because YKL-40 has not a relationship with NIHSS score. The CeO2 NPs and NACA combination are eligible option to develop antioxidant-based drug for the treatment of IS. As a complementary finding, the urea*lymphocyte/age is proposed as a NIHSS-based prognosis biomarker.

Cerium-Encapsulated SbIII-SeIV-Templating Polyoxotungstate for Electrochemically Sensing Human Multidrug Resistance Gene Segment.

A tower-like SbIII-SeIV-templating polyoxotungstate [H2N(CH3)2]12Na7H3[Ce0.5/Na0.5(H2O)5]2[SbSe2W21O75]2·50H2O (1) was synthesized, whose skeleton is assembled from two prolonged lacunary Dawson [SbSe2W21O75]13- units and two [Ce0.5/Na0.5(H2O)5]2+ linkers. The uncommon [SbSe2W21O75]13- unit can be viewed as a combination of one [SeW6O21]2- group grafted onto a trivacant Dawson [SbSeW15O54]11- subunit. The conductive composite 1-Au@rGO containing 1, gold nanoparticles, and reduced graphene oxide (rGO) was conveniently prepared, using which the 1-Au@rGO-based electrochemical genosensor was constructed for detecting human multidrug resistance gene segment. This work enriches structural types of dual-heteroatom-inserted polyoxometalates and promotes the application of polyoxometalates in genosensors.

Green synthesis of cerium oxide nanoparticles using zucchini peel extract for cytotoxic and photocatalytic properties.

The aim of this study is the green synthesis of cerium oxide nanoparticles (CeO2-NPs) using a natural capping agent and its application in water and wastewater treatment. This study presents the biosynthesis of CeO2-NPs by the exertion of a green method using zucchini (Cucurbita pepo) extract as a capping agent. Synthesized CeO2-NPs were distinguished through TGA/DTA, FT-IR, XRD, FESEM/TEM and EDX/PSA, and DRS procedures. According to the XRD pattern of NPs, the crystallinity structure was a face-centered cubic (fcc) with an Fm3m space group and the size was estimated at 30 nm. The spherical morphology of NPs was confirmed through FESEM/TEM images. In the following, the photocatalytic property of NPs was investigated by the decolorization of methylene blue (MB) dye within UV-A light. Also, the cytotoxicity of NPs on the CT26 cell line was evaluated through the MTT test, and no toxicity was observed in the results, which indicates their biocompatibility.

Catalytic-CO2-Desorption Studies of BZA-AEP Mixed Absorbent by the Lewis Acid Catalyst CeO2-γ-Al2O3.

Traditional organic amines exhibit inferior desorption performance and high regeneration energy consumption. The implementation of solid acid catalysts presents an efficacious approach to mitigate regeneration energy consumption. Thus, investigating high-performance solid acid catalysts holds paramount importance for the advancement and implementation of carbon capture technology. This study synthesized two Lewis acid catalysts via an ultrasonic-assisted precipitation method. A comparative analysis of the catalytic desorption properties was conducted, encompassing these two Lewis acid catalysts and three precursor catalysts. The results demonstrated that the CeO2-γ-Al2O3 catalyst demonstrated superior catalytic desorption performance. Within the desorption temperature range of 90 to 110 °C, the average desorption rate of BZA-AEP catalyzed by the CeO2-γ-Al2O3 catalyst was 87 to 354% greater compared to the desorption rate in the absence of the catalyst, and the desorption temperature can be reduced by approximately 10 °C. A comprehensive analysis of the catalytic desorption mechanism of the CeO2-γ-Al2O3 catalyst was conducted, and indicated that the synergistic effect of CeO2-γ-Al2O3 conferred a potent catalytic influence throughout the entire desorption process, spanning from the rich solution to the lean solution.

Optimization of adsorption performance of cerium-loaded intercalated bentonite by CCD-RSM and GA-BPNN and its application in simultaneous removal of phosphorus and ammonia nitrogen.

Excessive phosphorus (P) and ammonia nitrogen (NH3-N) in water bodies can lead to eutrophication of the aquatic environment. Therefore, it is important to develop a technology that can efficiently remove P and NH3-N from water. Here, the adsorption performance of cerium-loaded intercalated bentonite (Ce-bentonite) was optimized based on single-factor experiments using central composite design-response surface methodology (CCD-RSM) and genetic algorithm-back propagation neural network (GA-BPNN) models. Based on the determination coefficient (R2), mean absolute error (MAE), mean square error (MSE), mean absolute percentage error (MAPE), and root mean square error (RMSE), the GA-BPNN model was found to be more accurate in predicting adsorption conditions than the CCD-RSM model. The validation results showed that the removal efficiency of P and NH3-N by Ce-bentonite under optimal adsorption conditions (adsorbent dosage = 1.0 g, adsorption time = 60 min, pH = 8, initial concentration = 30 mg/L) reached 95.70% and 65.93%. Furthermore, based on the application of these optimal conditions in simultaneous removal of P and NH3-N by Ce-bentonite, pseudo-second order and Freundlich models were able to better analyze adsorption kinetics and isotherms. It is concluded that the optimization of experimental conditions by GA-BPNN has some guidance and provides a new approach to explore adsorption performance after optimizing the conditions.

Phytomediated-Assisted Preparation of Cerium Oxide Nanoparticles Using Plant Extracts and Assessment of Their Structural and Optical Properties.

Cerium oxide nanoparticles were obtained using aqueous extracts of Chelidonium majus and Viscum album. X-ray diffractometry analysis confirmed the crystalline structure of the synthesized cerium oxide nanoparticles calcined at 600 °C. Scanning electron microscopy, UV-Vis reflectance and Raman spectroscopy, XPS, and fluorescence studies were utilized to interpret the morphological and optical properties of these nanoparticles. The STEM images revealed the spherical shape of the nanoparticles and that they were predominantly uniform in size. The optical band gap of our cerium nanoparticles was determined to be 3.3 and 3.0 eV from reflectance measurements using the Tauc plots. The nanoparticle sizes evaluated from the Raman band at 464 cm-1 due to the F2g mode of the cubic fluorite structure of cerium oxide are close to those determined from the XRD and STEM data. The fluorescence results showed emission bands at 425, 446, 467, and 480 nm. The electronic absorption spectra have exhibited an absorption band around 325 nm. The antioxidant potential of the cerium oxide nanoparticles was estimated by DPPH scavenging assay.

Antioxidant and hypoglycemic potential of phytogenic cerium oxide nanoparticles.

Plants provide humans with more than just food and shelter; they are also a major source of medications. The purpose of this research was to investigate the antioxidant and hypoglycemic potential of green synthesized CeONPs using Mentha royleana leaves extract. The morphological and physicochemical features of CeONPs were evaluated by UV-Visible spectrophotometry, Scanning Electron Microscopy, Energy Dispersive X-rays and Fourier-transform infrared spectrometry, Dynamic light scattering, Atomic Force Microscopy, Zeta Potential. The average size range of synthesized CeONPs diameter between 46 and 56 nm, crystalline in shape, with Polydispersity index value of 0.2 and subatomic particles mean diameter was 4.5-9.1 nm. The antioxidant capability of CeONPs was assessed using DPPH, ABTS+, hydrogen peroxide, hydroxyl radical scavenging, and reducing power tests. The hypoglycemic potential of CeONPs was investigated using alpha-amylase, alpha-glucosidase, glucose absorption by yeast cells, and antisucrase. The effective concentrations were 500 and 1000 µg/ml found good in suppressing radical species. To explore the hypoglycemic potential of CeONPs, alpha-amylase, alpha-glucosidase, glucose absorption by yeast cell, and antisucrase assays were performed. Glucose absorb by yeast cells assay was tested for three distinct glucose concentrations: 5 mmol/L, 10 mmol/L, and 25 mmol/L. Green synthesize CeONPs showed a dose-dependent response, higher concentrations of CeONPs imposed a stronger inhibitory impact on the catalytic site of enzymes. This study suggest that CeONPs could possibly binds to the charge carrying species and act as competitive inhibitor which slow down the enzyme substrate reaction and prevents enzymatic degradation. The study's findings were outstanding, which bodes well for future medicinal applications of CeONPs.

High-sensitive XANES analysis at Ce L2-edge for Ce in bauxites using transition-edge sensors: Implications for Ti-rich geological samples.

Accurate determination of cerium (Ce) valence state is important for interpreting the Ce anomaly in geological archives for (paleo)redox reconstruction. However, the routine application of Ce L3-edge X-ray absorption near-edge structure (XANES) spectroscopy for detecting trace Ce in geological samples can often be restricted by coexisting titanium (Ti) due to the proximity of their fluorescence emission lines. Therefore, the signal-to-noise ratio of Ce L3-edge XANES spectra may not be sufficiently high for high-quality spectroscopic analysis. This study introduces a semi-quantitative approach appropriate for Ti-rich, Ce-dilute geological materials by synchrotron-based X-ray measurement at the Ce L2-edge. First, the results confirm that Ce L2-edge XANES spectra are able to avoid overlapping Ti Kß emissions and provide more reliable information on the Ce valence state in Ti-rich materials relative to L3-edge XANES. Moreover, the application of transition-edge sensor (TES) could reach the higher sensitivity with better energy resolution than conventional silicon drift detector (SDD) to detect fluorescence X-ray (Ce Lß1). The investigation on bauxites developed from the Columbia River Basalts shows that combining Ce L2-edge XANES and TES allows for resolving weak Ce fluorescence lines at the L2-edge from Ti-rich, Ce-dilute samples (Ti/Ce mass ratio up to ∼6000, tens of ppm Ce). The outcome emphasizes the practical possibility of investigating Ce redox state in Ti-rich geological samples.

Accumulation and distribution characteristics of rare earth elements (REEs) in the naturally grown marigold (Tagetes erecta L.) from the soil.

Rare earth elements (REEs) are considered environmental pollutants that have received extensive attention recently. The accumulation of REEs in plants is important because REEs can eventually enter the human body via the food chain. Marigolds are widely utilized as medicinal and commercial plants in medicine, feed, and therapeutics. Due to the extremely high demand for marigold in global, it is urgent to investigate the accumulation and distribution of REEs in marigold plants to reduce human and animal health risks. Marigold leaves tended to bioaccumulate the highest amounts of REEs from soil compared with other tissues. The distribution patterns of REEs in marigold were similar to those in the rhizosphere soil, which was enriched in light rare earth elements. Cerium accumulated most in marigold and soil, accounting for nearly 50% of ΣREEs, followed by lanthanum, neodymium, and yttrium. Roots were the most susceptible tissue affected by soil REE concentration, and a significant positive correlation was observed for REEs in the roots of marigold and soils (R = 0.87), while no significant correlation was observed for REEs in soils and other tissues. REEs were poorly transferred from soil to marigold, with bioaccumulation factor values for all tissues of marigold less than one. Additionally, REEs exhibited a positive correlation with Al and Fe in the roots, stems, leaves, and flowers of marigold. The present research revealed the biological interactions between marigold and soil and the distribution of REEs in various parts of marigold. It provides a reference for large-scale commercial cultivation and potential environmental risk in the future.

Alginate Beads Containing Cerium-Doped Mesoporous Glass and Curcumin: Delivery and Stabilization of Therapeutics.

Cancer is a leading cause of death worldwide, its genesis and progression are caused by homeostatic errors, and reactive oxygen species play a major role in promoting aberrant cancer homeostasis. In this scenario, curcumin could be an interesting candidate due to its versatile antioxidant, anti-inflammatory, anti-tumor, anti-HIV, and anti-infection properties. Nonetheless, the major problem related to its use is its poor oral bioavailability, which can be overcome by encapsulating it into small particles, such as hydrogel beads containing mesoporous silica. In this work, various systems have been synthesized: starting from mesoporous silica glasses (MGs), cerium-containing MGs have been produced; then, these systems have been loaded with 4 to 6% of curcumin. Finally, various MGs at different compositions have been included in alginate beads. In vitro studies showed that these hybrid materials enable the stabilization and effective delivery of curcumin and that a synergic effect can be achieved if Ce3+/Ce4+ and curcumin are both part of the beads. From swelling tests, it is possible to confirm a controlled curcumin release compartmentalized into the gastrointestinal tract. For all beads obtained, a curcumin release sufficient to achieve the antioxidant threshold has been reached, and a synergic effect of cerium and curcumin is observed. Moreover, from catalase mimetic activity tests, we confirm the well-known catalytic activity of the couple Ce3+/Ce4+. In addition, an extremely good radical scavenging effect of curcumin has been demonstrated. In conclusion, these systems, able to promote an enzymatic-like activity, can be used as drug delivery systems for curcumin-targeted dosing.

Identification of a TonB-Dependent Receptor Involved in Lanthanide Switch by the Characterization of Laboratory-Adapted Methylosinus trichosporium OB3b.

Two methanol dehydrogenases (MDHs), MxaFI and XoxF, have been characterized in methylotrophic and methanotrophic bacteria. MxaFI contains a calcium ion in its active site, whereas XoxF contains a lanthanide ion. Importantly, the expression of MxaFI and XoxF is inversely regulated by lanthanide bioavailability, i.e., the "lanthanide switch." To reveal the genetic and environmental factors affecting the lanthanide switch, we focused on two Methylosinus trichosporium OB3b mutants isolated during routine cultivation. In these mutants, MxaF was constitutively expressed, but lanthanide-dependent XoxF1 was not, even in the presence of 25 µM cerium ions, which is sufficient for XoxF expression in the wild type. Genotyping showed that both mutants harbored a loss-of-function mutation in the CQW49_RS02145 gene, which encodes a TonB-dependent receptor. Gene disruption and complementation experiments demonstrated that CQW49_RS02145 was required for XoxF1 expression in the presence of 25 µM cerium ions. Phylogenetic analysis indicated that CQW49_RS02145 was homologous to the Methylorubrum extorquens AM1 lanthanide transporter gene (lutH). These findings suggest that CQW49_RS02145 is involved in lanthanide uptake across the outer membrane. Furthermore, we demonstrated that supplementation with cerium and glycerol caused severe growth arrest in the wild type. CQW49_RS02145 underwent adaptive laboratory evolution in the presence of cerium and glycerol ions, resulting in a mutation that partially mitigated the growth arrest. This finding implies that loss-of-function mutations in CQW49_RS02145 can be attributed to residual glycerol from the frozen stock. IMPORTANCE Lanthanides are widely used in many industrial applications, including catalysts, magnets, and polishing. Recently, lanthanide-dependent metabolism was characterized in methane-utilizing bacteria. Despite the global demand for lanthanides, few studies have investigated the mechanism of lanthanide uptake by these bacteria. In this study, we identify a lanthanide transporter in Methylosinus trichosporium OB3b and indicate the potential interaction between intracellular lanthanide and glycerol. Understanding the genetic and environmental factors affecting lanthanide uptake should not only help improve the use of lanthanides for the bioconversion of methane into valuable products like methanol but also be of value for developing biomining to extract lanthanides under neutral conditions.

Cerium improves the physiology and medicinal components of Dendrobium nobile Lindl. under copper stress.

Heavy metal stress affects the quality of medicinal plants, and rare earth elements can effectively alleviate heavy metal stress. In this paper, we investigated the effects of rare earth element cerium (0, 5, 10, 20, 40, 80, and 160 mg/L) on the physiological and medicinal components of Dendrobium nobile Lindl. under copper (200 mg/L) stress. The results revealed that cerium (Ce) had a good alleviating effect on copper (Cu) stress, low concentrations of Ce (10-20 mg/L) significantly improved the resistance and medicinal qualities of the plant such as polysaccharide, polyphenol and flavonoid, it also increased the content of photosynthetic pigment, proline, soluble sugar and soluble protein of D. nobile Lindl., effectively balance the osmotic pressure and the generation and removal of reactive oxygen species in the plant, thereby the toxic effect of copper on D. nobile Lindl. is alleviated. From the point of view of the treatment time when the optimal relieving concentration appeared, the optimal concentration for relieving antioxidant enzyme activity all appeared at the treatment time of 10 d, the optimum concentrations of other indicators all appeared at the treatment time of 15 d. Overall, this study suggests that the optimum level of Ce (10-20 mg/L) might be promising for alleviating the adverse impacts of copper stress and promoting the accumulation of medicinal components in D. nobile Lindl.

Biosynthesized Cerium Oxide Nanoparticles CeO2NPs: Recent Progress and Medical Applications.

Currently, nanobiotechnology represents a leading research area that primarily focuses on the safe, eco-friendly synthesis of biocompatible metal oxide nanoparticles. Among these, biosynthesized cerium oxide nanoparticles have particularly received attention in medical science as their unique surface chemistry and dual oxidation state make them excellent antioxidants and freeradical scavengers. Currently, plant extracts are widely explored and employed for the biosynthesis of CeO2NPs. Other biological sources such as marine oyster shell extract, egg-white, biopolymers, e.g., chitosan, agarose, alginate, and others, have also been successfully used for the fabrication of CeO2NPs. This review highlights the recent progress in the biosynthesis of CeO2NPs and the investigation of their medical use as biocompatible anticancer, antibacterial, antifungal, antioxidant, antidiabetic, and wound healing agents. Furthermore, prospects associated with the use of biogenic CeO2NPs in developing novel products in the medical sector are also highlighted.

Selenium nanoparticles reduce Ce accumulation in grains and ameliorate yield attributes in mung bean (Vigna radiata) exposed to CeO2.

Exposure of crops to CeO2 nanoparticles (nCeO2) in agricultural environments impact crop quality and human health. In this regard, the effects of selenium nanoparticles (nSe) on the yield and quality of Vigna radiata (L.) exposed to nCeO2 were investigated. The experiment was carried out as a factorial with two factors: NPs (nCeO2, and nSe) as factor one and concentrations as factor two [(0, 250, 500 and 1000 mg/L nCeO2; 0, 25, 50 and 75 mg/L nSe)]. Nanoparticles were foliar applied to 45-day old mung bean shoot in two steps and one-week interval. At 250-1000 mg/L, nCeO2 increased P, protein and Ce accumulation in grain. Additionally, at 1000 mg/L, the nCeO2, significantly decreased seed number, yield, Fe, and Zn storage in seeds. Conversely, at 25 and 50 mg/L, nSe stimulated the growth and yield of mung bean, and significantly increased P, Fe, Zn, and Se in seeds, but reduced the protein content in seeds. The Se25+Ce250 and Se50+Ce250 significantly increased pod number, seed number, grain weight, yield, Fe, Zn and Se storage in grains. In contrast, the Ce accumulation in seeds decreased in all combination treatments (nCeO2 + nSe) compared to their respective single nCeO2 treatments. Moreover, in the plants exposed to high nCeO2 concentrations, nSe application resulted in undamaged vacuoles, less starch granules' accumulation, significant yield improvement, and elevated Fe, Se, and Zn in seeds. Data suggest that selenium nanoparticles prevent nCeO2 stress in mung bean and improve grain production and quality.

Tea polyphenols mediated biogenic synthesis of chitosan-coated cerium oxide (CS/CeO2) nanocomposites and their potent antimicrobial capabilities.

In the present study, we hypothesized that novel nanocomposites of chitosan-coated cerium oxide (CS/CeO2 NCs) derived from aqueous extracts of tea polyphenols would be stabilized and reduced by using green chemistry. The UV-visible spectrum of the synthesized material revealed an SPR peak at 279 nm, and the morphological characteristics of nanoparticles (NPs) as a uniformly distributed spherical shape with a size range of 20 nm were confirmed by field emission scanning electron microscopy (FESEM). The Fourier transform infrared spectroscopy (FTIR) spectrum illustrated the amino groups of chitosan-coated with CeO2 NPs on the surface. While, the hydrodynamic size (376 nm) and surface charge (+ 25.0 mV) of particles were assessed by dynamic light scattering (DLS), and the existence of oxidation state elements Ce 3d, O 1 s, and C 1 s was identified by employing X-ray photoelectron spectroscopy (XPS). A cubic fluorite polycrystalline structure with a crystallite size of (5.24 nm) NPs was determined using an X-ray Diffractometer (XRD). The developed CS/CeO2 NCs demonstrated excellent antibacterial and antifungal efficacy against foodborne pathogens such as Escherichia coli, Staphylococcus aureus, and Botrytis cinerea with zone of inhibition of 13.5 ± 0.2 and 11.7 ± 0.2 mm, respectively. The results elucidated the potential of biosynthesized CS/CeO2 NCs could be utilized as potent antimicrobial agents in the food and agriculture industries.

Balancing acid and redox sites of phosphorylated CeO2 catalysts for NOx reduction: The promoting and inhibiting mechanism of phosphorus.

The role of phosphorus in metal oxide catalysts is still controversial. The precise tuning of the acidic and redox properties of metal oxide catalysts for the selective catalytic reduction in NOx using NH3 is also a great challenge. Herein, CeO2 catalysts with different degrees of phosphorylation were used to study the balance between the acidity and redox property by promoting and inhibiting effects of phosphorus. CeO2 catalysts phosphorylated with lower phosphorus content (5 wt%) exhibited superior NOx reduction performance with above 90% NOx conversion during 240-420 °C due to the balanced acidity and reducibility derived from the highest content of Brønsted acid sites on PO43- to adsorb NH3 and surface adsorbed oxygen species. Plenty of PO3- over CeO2 catalysts phosphorylated with the higher phosphorus content (≥ 10 wt%) significantly disrupted the balance between the acidity and the redox property due to the reduced acid/redox sites, which resulted in the less active NOx species. The mechanism of different structural phosphorus species (PO43- and PO3-) in promoting or inhibiting the NOx reduction over CeO2 catalysts was revealed. This work provides a novel method for qualitative and quantitative study of the relationship between acidity/redox property and activity of catalysts for NOx reduction.