Ceria Nanoparticles Research Articles

Differential effect of cerium nanoparticles on the viability, redox-status and Ca2+-signaling system of cancer cells of various origins.

The present study aims to understand the molecular mechanism underlying the therapeutic effect of cerium nanoparticles (CeNPs) in oncology. Cancer cells were treated with different concentrations of pure nanocerium of different sizes synthesized by laser ablation. Due to the not insignificant influence of surface defects and oxygen species on the ROS-modulating properties of cerium nanoparticles, the nanoparticles were not coated with surfactants or organic molecules during synthesis, which could potentially inhibit a number of pro-oxidative effects. Reactive oxygen species (ROS) production, expression of genes encoding redox-status proteins, selenoproteins and proteins regulating cell death and endoplasmic reticulum stress (ER-stress) were investigated as indicators of the molecular mechanism of cancer cell death. Studies were conducted on the effects of cerium nanoparticles on the Ca2+ signaling system of cancer cells of different origins. Mouse fibroblasts (L-929cell line) were used as non-cancerous ("normal") cells for which a whole series of experiments were performed, and a comparative analysis of the effects of nanoceria. It was found that 75nm-sized cerium nanoparticles did not affect the redox-status and ROS production of cancer cells. In fibroblast cells, however, this nanoparticle diameter led to a deterioration of the cellular redox status and ROS production in a wide range of nanoparticle concentrations. Larger nanoparticles (100nm-sized and 160nm-sized), on the other hand, showed a different effect on cancer cells of different origins. In mouse fibroblast L-929cells, however, 100nm-sized or 160nm-sized CeNPs acted in a high concentration range to disrupt mitochondrial membrane potential and activate early apoptosis. High concentrations of CeNPs were required to increase ROS production, reduce redox-status and induce apoptosis in human A-172 glioblastoma cells compared to the hepatocellular carcinoma cell line HepG2 and the breast cancer cell line MCF-7. In the A-172 glioblastoma cells, ER-stress was also not activated and their Ca2+ signaling system was activated by a significantly higher concentration of CeNPs, which could also contribute to the formation of tolerance of this cancer cell line to nanoceria. The Ca2+ signaling system of mouse fibroblasts was found to be highly sensitive to activation by nanoceria and the cells produced Ca2+ signals with higher amplitude compared to A-172 and MCF-7cells.

Carvacrol/cyclodextrin/ceria nanoparticle/hyaluronate hybrid microneedle for promoted diabetic wound healing through the modulation of microenvironment.

Delayed healing due to the persistent microenvironment disorder caused by the hyperglycemia and persistent inflammatory reaction is a core pathological characteristic of diabetic wound. Topical microenvironment modulation represents an important avenue to address delayed healing issue. Microneedles are powerful tools for topical microenvironment modulation as they can effectively deliver therapeutic ingredients into the shallow surface layer of the wound based on their depth-limited tissue penetration capability. Herein, a hybrid microneedle composed of carvacrol (CV), cyclodextrin (CD), mesoporous ceria nanoparticles (MCNs) and hyaluronate (HA) is constructed with objective to modulate the microenvironment within the diabetic wound. The hybrid microneedle is constructed via a two-stage process comprising three stepwise embedding procedures in the first stage and four microneedle casting procedures in the second stage. The physical, chemical and antibacterial performances, as well as the in vitro and in vivo therapeutic potentials, of the hybrid microneedle are evaluated. The therapeutic ingredients, mainly CV and MCNs, incorporated in the microneedle can be readily released into the diabetic wound, and effective microenvironment modulation is realized through the designed antibacterial, antioxidant and anti-inflammatory functions. Consequently, the tissue reconstruction processes including cell proliferation and migration, angiogenesis, and collagen deposition are accelerated due to the improved microenvironment.

Hybridizing Fabrications of Gd-CeO2 Thin Films Prepared by EPD and SILAR-A+ for Solid Electrolytes

Thin films of gadolinium-doped ceria (GDC) nanoparticles were fabricated as electrolytes for low-temperature solid oxide fuel cells (SOFCs) by combining electrophoretic deposition (EPD) and the successive ionic layer adsorption and reaction-air spray plus (SILAR-A+) method. The Ce1−xGdxO2−x/2 solid solution was synthesized using hydrothermal (HY) and solid-state (SS) procedures to produce high-quality GDC nanoparticles suitable for EPD fabrication. The crystalline structure, cell parameters, and phases of the GDC products were analyzed using X-ray diffraction. Variations in oxygen vacancy concentrations in the GDC samples were achieved through the two synthetic methods. The ionic conductivities of pressed pellets from the HY, SS, and commercial G0.2DC samples, measured at 150 °C, were 0.6 × 10−6, 2.6 × 10−6, and 2.9 × 10−6 S/cm, respectively. These values were determined using electrochemical impedance spectroscopy (EIS) with a simplified equivalent circuit method. The morphologies of G0.2DC thin films prepared via EPD and SILAR-A+ processes were characterized, with particular attention to surface cracking. Crack-free GDC thin films, approximately 730–1200 nm thick, were successfully fabricated on conductive substrates through the hybridization of EPD and SILAR-A+, followed by hydrothermal annealing. EIS and ionic conductivity (1.39 × 10⁻⁹ S/cm) measurements of the G0.2DC thin films with thicknesses of 733 nm were performed at 300 °C.

Ceria Nanoparticles Improve the Quality of Aging Oocytes in Mice by Enhancing ROS Scavenging Ability

Ceria Nanoparticles Improve the Quality of Aging Oocytes in Mice by Enhancing ROS Scavenging Ability

Cerium oxide nanoparticles decorated on graphene oxide nanosheets as battery-type cathode material for supercapacitors.

Designing advanced materials that effectively mitigate the poor cycle life of battery-type electrodes with high specific capacities is crucial for next-generation energy storage systems. Herein, graphene oxide-ceria (GO-CeO2) nanocomposite synthesized via a facile wet chemical route is explored as cathode for high-performance supercapacitors. The morphological analysis suggests fine ceria (CeO2) nanoparticles dispersed over ultrathin graphene oxide (GO) sheets while structural studies reveal face-centered cubic phase of CeO2 in the nanocomposite. In-depth electrochemical performance investigation of the nanocomposite in 6M KOH aqueous electrolyte demonstrated its excellent battery-type behavior with least ion diffusion resistance and a superior cycle life resulting from the synergistic effect of redox-active CeO2 and 2D GO with abundant oxygen functionalities. Specifically, GO-CeO2 composite electrode delivered a maximum specific capacitance of 625.9F/g (52.2mAh/g) at 3 A/g current density, which is substantially higher than the capacitance values obtained for GO and CeO2 electrodes, and demonstrated an excellent cycling stability with∼100% capacitance retention after 10,000 CV cycles. Furthermore, a novel aqueous asymmetric supercapacitor (ASC) is explored with GO-CeO2 as positive and iron(III) oxyhydroxide (FeOOH) as negative electrode material in 6M KOH electrolyte which has also displayed good energy-power density combination along with excellent cycle stability. The study thus endorses rational design of nanocomposite materials with suitable functionalities as an excellent strategy in augmenting the performance of futuristic energy storage devices.

Cu doped ceria nanoparticles-rhodamine B as a novel chemiluminescence system and its application for nitrite detection in water and food samples.

Fe, Ni, and Cu doped ceria nanoparticles (CeNPs) were prepared with a simple and one-pot hydrothermal synthesis method. We investigated the chemiluminescence (CL) interaction between these NPs and rhodamine B (Rh B) and found that the highest CL intensity was related to the Rh B- Cu doped CeNPs. We assigned that to the higher catalytic property of Cu doped NPs compared to the others. Cu doped CeNPs have been applied for the first time as a catalyst in chemiluminescence reactions. Rh B- Cu doped CeNPs reaction was introduced as a novel CL system, and its mechanism was studied. Considering the sensitivity, simplicity, portability, and rapidness of the CL methods, we applied the introduced reaction to the development of a CL sensor for nitrite monitoring. In the presence of nitrite, the CL intensity of the system decreased, and there was a linear relationship between the CL intensity and nitrite concentration in the range 0.5-100 µM. Based on this fact, a sensitive and selective CL sensor with the detection limit of 0.2µM was established for nitrite detection in various food and water samples.

Autocatalytic Ceria Nanoparticle-Embedded Tilapia Collagen Hydrogels as Enhanced Antioxidative and Long-Lasting Dermal Fillers for Photoaged Skin.

Excessive reactive oxygen species (ROS) generated by ultraviolet (UV) irradiation significantly contribute to photoaging by increasing the level of matrix metalloproteinases (MMPs), accelerating collagen degradation. Commercial dermal fillers offer temporary wrinkle reduction via volume enhancement. In this study, we propose tilapia-derived collagen hydrogels embedded with ceria nanoparticles (Ce@Col gels) as long-lasting dermal fillers for UVB-induced photoaging. Ceria nanoparticles (CeNPs) significantly enhance the stability of the collagen matrix against enzymatic degradation. These gels exhibit mechanical stability and injectability comparable to those of commercial alternatives. Additionally, CeNPs effectively eliminate ROS to suppress MMP production, curbing both collagen degradation and inflammatory responses. In a UVB-induced photoaging mouse model, the Ce@Col gels significantly reduced the level of oxidative stress in the skin, decreased the number of wrinkles, reduced epidermal thickness, and decreased levels of aging-related biomarkers while increasing the level of collagen deposition. These antiaging effects persisted for seven months post-injection, highlighting Ce@Col gels as a promising approach for prolonged collagen regeneration and sustained anti-inflammatory benefits in photoaged skin.

Experimental Investigation and Prediction of Vibrational Characteristics in Diesel Engines with Diphenylamine Antioxidant and Ceria Nanoparticle Enriched Biodiesel

Experimental Investigation and Prediction of Vibrational Characteristics in Diesel Engines with Diphenylamine Antioxidant and Ceria Nanoparticle Enriched Biodiesel

FTIR study of low-temperature CO adsorption on reduced ceria nanoparticles with different morphology: A comparison with oxidized samples

FTIR study of low-temperature CO adsorption on reduced ceria nanoparticles with different morphology: A comparison with oxidized samples

An electrochemical immunosensor based on a nano-ceria integrated microfluidic chip for interleukin-8 biomarker detection.

Interleukin-8 (IL8) is an important cytokine that plays a significant role in tumor growth and angiogenesis across various malignant tumors, including oral squamous cell carcinoma (OSCC). It is an important biomarker for oral cancer; therefore, its early and accurate detection in bodily fluid reduces morbidity and mortality rates in cancer patients. The work presents the development of a label-free microfluidic miniaturized electrochemical immunosensor for IL8 biomarker detection at low concentration in saliva samples. A rapid, sensitive and selective biosensing platform was developed for IL8 detection using a nano-ceria integrated microfluidic system. The synthesized nano-ceria particles (8.13 nm) were employed to enhance the electrochemical biosensing signal and sensitivity of the biosensor due to their high catalytic properties and large surface area. For this, microfluidic chip was prepared by Indium tin oxide (ITO) (3 × 4 cm) containing three electrode patterns of working, reference and counter electrode. These electrode patterns were developed using a maskless photolithography technique and a polydimethylsiloxane (PDMS) mold created a 200 μm wide microchannel which was bound to the susbtrate using plasma treatment. Spectroscopy and microscopy techniques were used to confirm the synthesis of nano-ceria. Furthermore, electrode surface modifications were achieved by immobilization of chemically activated antibodies of IL8, as verified by Fourier transform-infrared spectroscopy (FT-IR). Furthermore, differential pulse voltammetry (DPV) was utilized to investigate electrochemical parameters and conduct biosensing studies. The developed electrochemical microfluidic biosensing platform works for an IL8 antigen in the concentrations ranging from 0.004 to 10 ng mL-1 with a limit of detection (LOD) and limit of quantification (LOQ) of 0.0001 ng mL-1 and 0.0006 ng mL-1, respectively. Moreover, the developed electrochemical biosensing platform was validated using human saliva samples, achieving percentage recovery within an acceptable range.

The Stability Evaluation of Ceria Slurry Using Polymer Dispersants with Varying Contents for Chemical Mechanical Polishing Process.

The chemical mechanical polishing/planarization (CMP) is essential for achieving the desired surface quality and planarity required for subsequent layers and processing steps. However, the aggregation of slurry particles caused by abrasive materials can lead to scratches, defects, increased surface roughness, degradation the quality and durability of the finished surface after milling processes during the CMP process. In this study, ceria slurry was prepared using polymer dispersant with zinc salt of ethylene acrylic acid (EAA) copolymer at different contents of 5, 6, and 7 wt% (denoted as D5, D6, and D7) to minimize particle aggregation commonly observed in CMP slurries. Among them, the D7 sample exhibited smaller particle sizes compared to commercial ceria slurry, which was attributed to the influence of the carboxyl groups (-COOH) of the polyacrylic acid polymer coating the ceria particles. It is believed that the polymer dispersant more effectively adsorbs onto the particle surfaces, increasing electrostatic repulsion between particles and thereby reducing particle size. Furthermore, the stability of the prepared slurry was evaluated under extreme conditions over three months at 25 °C (both open and closed conditions), 4 °C, and 60 °C. The D7 slurry remained stable with no significant changes observed. In addition, the prepared D7 ceria slurry exhibited a slightly higher removal rate (RR) and better uniformity, which can be attributed to the smaller particle sizes of the ceria nanoparticles compared to those in the commercial slurry. This suggests that the colloidal stability of the D7 ceria slurry is superior to that of the commercial ceria slurry.

Controlled Release of Ceria and Ferric Oxide Nanoparticles via Collagen Hydrogel for Enhanced Osteoarthritis Therapy (Adv. Healthcare Mater. 32/2024)

Controlled Release of Ceria and Ferric Oxide Nanoparticles via Collagen Hydrogel for Enhanced Osteoarthritis Therapy (Adv. Healthcare Mater. 32/2024)

Evidence for low bioavailability of dietary nanoparticulate cerium in a freshwater food chain.

Radioactive 141Ce in ionic (I-Ce), nano (N-Ce, 11 ± 9 nm mean primary particle size ± standard deviation) and micron-sized (M-Ce, 530 ± 440 µm) forms associated with natural and artificial diets in natural river water and synthetic freshwater were used to measure the real-time biokinetics of dietary 141Ce assimilation in a freshwater food chain. The model food chain consisted of microalgae (Raphidocelis subcapitata), snails (Potamopyrgus antipodarum) and prawns (Macrobrachium australiense). Pulse-chase experiments showed that 91-100 % of all forms of cerium associated with all diets and water types were eliminated from the digestive system of the snail and prawn within 24 h, with no detectable cerium assimilation. The prawn and snail median elimination times (ET50) and elimination rates (Ke) for all cerium forms ranged from 0.05 to 1.7 d, and 30 to >100 % per d, respectively. The pulse-chase results were supported by the autoradiographic evidence for N-Ce and M-Ce that confirmed no detectable assimilation and translocation within the tissue of the prawn over time. In contrast, the more soluble I-Ce was found to be associated in low quantities with the hepatopancreas in the prawn confirming that the lack of dissolution by N-Ce and M-Ce in the digestive environment of these organisms makes these forms less bioavailable. In addition, hetero-agglomeration of N-Ce and M-Ce resulted in particles that did not dissociate in digestive fluids and were too large to be assimilated thereby making them non-bioavailable. Based on the results from this study and from the literature review, the risk of N-Ce biomagnification and chronic dietary toxicity in freshwater ecosystems is no greater than the risk associated with M-Ce or I-Ce.

Ligand-to-Metal Ratio Governs Radical-Scavenging Ability of Malate-Stabilised Ceria Nanoparticles.

Cerium dioxide sols stabilised with L-malic acid were shown to exhibit significant antioxidant activity towards alkyl peroxyl radicals in the range of ligand:CeO2 molar ratios of 0.2-1 (0.2:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1 and 1:1). The antioxidant activity of cerium dioxide nanoparticles greatly depended on L-malic acid content and increased by 8 times when the ligand:CeO2 molar ratio increased from 0.2:1 to 0.4:1. An estimate of the ligand:CeO2 molar ratio required to ensure complete surface coverage of CeO2 nanoparticles with malate anions resulted in a value of 0.2. Aggregation degree of CeO2 nanoparticles depends on the ligand:CeO2 molar ratio. In the range of ligand:CeO2 molar ratios 0.2-0.4, the size of aggregates decreased by an order of magnitude. The antioxidant capacity of 1 mM malate-stabilised cerium dioxide (0.2:1) relative to sodium ascorbate was 0.012 ± 0.001 mM. The antioxidant activity of cerium dioxide stabilised with L-malic acid at a ligand:CeO2 molar ratio of 0.2:1 was 80 times less than the antioxidant activity of sodium ascorbate. Cerium dioxide nanoparticles stabilised with L-malic acid did not demonstrate a cytotoxic effect against human mesenchymal stem cells, in a wide range of concentrations (10-3-10-5 M), and their proliferation was stimulated after 72 h of cultivation. The results obtained show new possibilities for the design of biocompatible ceria-based nanomaterials with tunable pro- and antioxidant properties; these materials can further be assessed in view of their potential for treating oxidative stress-related disorders.

Effect of Cerium Nanoparticles and/or Lanthanum on Different Physiological activities in Adult Male Albino Rats

Effect of Cerium Nanoparticles and/or Lanthanum on Different Physiological activities in Adult Male Albino Rats

Transport Properties and Morphology of Cerium Oxide Composite Sulfonated(Poly Arylene Ether Sulfone) Membranes for Application in Heavy-Duty Fuel Cell Vehicles

Fuel cells for Heavy Duty Vehicles (HDVs) offer easy scalability and the potential for critical reduction in CO2 emissions. During the drive cycles of HDVs, the fuel cells will operate over a range of temperatures, with increases while climbing up steep gradients. Operating temperatures above 90°C will be necessary, along with low relative humidity (RH) due to the need to avoid pressurization of gases. Therefore, Proton Exchange Membranes (PEMs) for HDV applications need to be suitable over this range of conditions, including functioning at high temperatures and low relative humidity. Moreover, the membranes should not swell extensively when more water is present.In this study, sulfonated poly (arylene ether sulfone) multiblock copolymers were modified with the incorporation of clusters of modified cerium oxide nanoparticles to form composites. These synthesized novel membranes approach operational proton conductivity requirements for HDV vehicles, with conductivity of 15mS/cm at 120°C and 25% relative humidity, remarkably avoiding the typical large decrease in conductivity observed below 70% RH in non-fluorinated PEMs. One purpose of this study is to understand the water, proton, and polymer interactions within these membranes. The cerium nanoparticles and sulfonamide clusters play a critical role in the membrane, affecting conductivity, and water transport, especially at high temperatures and low relative humidity, while also suppressing swelling of the membrane. Membrane proton conductivity is also strongly influenced by physical properties such as water uptake and dimensional swelling behavior, which is further impacted by polymer morphology. To probe the dynamics of the components, the diffusion coefficient and relaxation time of water in the membrane and the protonic conductivity of the membrane as functions of membrane water content are analyzed using nuclear magnetic resonance (NMR) measurements and water uptake measurements. Film property and morphology changes are evaluated using Transmission Electron Microscopy (TEM) and Small-Angle X-ray Scattering (SAXS). This study demonstrates the advantageous and non-linear benefits of closely packed acid clusters with cerium oxide composites on membrane functionality under HDV operating conditions.

Insight into the Modification of the Low-Pt Electrocatalysts By the Defective Metal Oxide Additives: The Effect on the Oxygen Reduction Reaction in Acid Media

The global rise in energy consumption combined with severe environmental issues and climate change has promoted the development of green alternative technologies such as low-temperature proton exchange membrane fuel cells (PEMFCs). However, the performance and operational cost of PEMFC largely depend on the application of highly expensive state-of-the-art Pt-based systems, which are so far the most effective catalysts for the oxygen reduction reaction (ORR) at the fuel cell’s cathode. The widespread commercialization of the PEMFC technology has also been complicated by the limited lifetime of catalytic systems due to the instability of carbon supports as well as Pt catalytic centers. Due to these facts, it is of great significance to gain an in-depth insight into the ORR mechanism to optimize the activity of the ORR catalytic centers and their more efficient utilization while minimizing the Pt content without loss of performance and durability, which are essential features to ensure wider use of the low-temperature hydrogen-oxygen fuel cell systems. One of the reasonable strategies for ameliorating stability, and selectivity of carbon-supported low Pt content electrocatalysts for the ORR in acid media is their functionalization by selected nanostructured non-noble metal oxides (MOx)1. The strong mutual interactions between all components in such hybrid material (Pt, C, MOx) are capable of tuning the Pt electronic structure at the electrocatalytic interface, thus promoting centers for the adsorption of oxygen and the cleavage of O=O bonds as well as the durability of the carbon carriers can be improved under highly aggressive acidic conditions. Additionally, the application of metal oxide co-catalysts which are capable of inducing the decomposition of hydrogen peroxide and/or scavenging of free radicals can make a significant contribution to improving the durability and overall efficiency of fuel cells.Due to the unique structure, redox ability, oxygen vacancies, and other features resulting from the 4f electronic configuration of cerium, in the present studies, we synthesis the reduced CeOx nanostructured and investigate the influence of such additive on the stability and selectivity of low-Pt content electrocatalysts in the oxygen reduction reaction (ORR) in acidic media. The stable oxide phases with the tailored redox properties and the presence of oxygen vacancies were obtained by controlling their morphology and composition. Preparation of small ceria nanoparticles by microwave-assisted hydrothermal method and introduction of various dopants (e.g. Pr, Nb, Cu) into these oxide structures improve its reducibility and non-stoichiometry phase content, optimizing important parameters for catalytic activity. The received results revealed that the CeOx/M-CeOx additive is allowed to obtain a lower amount of undesirable H2O2 produced during the ORR and improve the Pt/C stability. It is assumed that the improved durability and the better selectivity towards 4e– reduction of oxygen of the modified catalyst result from the defective cerium oxide properties and strong interactions between all components. Acknowledgments: This research was funded by the National Science Center (Poland) under Sonatina Project (2022/44/C/ST5/00077) and under the auspices of the European Union EIT Raw Materials ALPE 19247 Project (Specific Grant Agreement No. EIT/RAW MATERIALS/SGA2020/1).

An electrochemiluminescence sensor for ultrasensitive determination of tyrosine based on ceria nanomaterial as a novel luminophor

BackgroudRecently, optical nanomaterials have attracted much attention in the field of electrochemiluminescence (ECL). Nanostructured ceria possessed unique optical properties, and it's always used for constructing ECL sensor as catalyst for improving sensing performance, while the ECL property of ceria is rarely studied. In fact, it could be the potential candidate for applying in ECL sensors based on size and shape dependency optical property caused by the quantum scale effects. Therefore, new simple and efficient ceria nanomaterial used as luminophor for constructing the ECL sensor have aroused more research interest and motivation. (91 words). ResultsIn the work, three kinds of nanostructured ceria, ceria nano-cube (CeO2-NC), ceria nano-rods (CeO2-NR) and ceria nano-particle (CeO2-NP), have been prepared by hydrothermal method, and CeO2-NC with the less oxygen vacancy has the highest ECL signal. Moreover, how the shape affects the ECL property was investigated in detail, especially the oxygen vacancy on the surface of the ceria. The less of oxygen vacancy content of CeO2 nanomaterials is more favorable the ECL reaction. Furthermore, a novel ECL sensor was constructed based on reduced graphene oxide (rGO), Au nano-particle (AuNPs) and CeO2-NC for Tyrosine (Tyr) determination owing to the electron transform between the luminous of ceria and Tyr resulting in the cathodic ECL intensity quenched correspondingly, and it has possessed excellent sensing performance with a linear range of 0.005–20 nmol/L and the limit of detection (LOD) value of 1.7 fmol/L (141 words) Significance and noveltyThe proposed method demonstrated excellent selectivity and ultra-sensitivity toward Tyr, which had been used for the determination of Tyr in human serum successfully, possessing outstanding analytical performance. Therefore, nanostructured ceria is a new category of efficient and promising luminophore, which would open new avenues for the potential application in the field of ECL sensing for clinical diagnosis. (57 words).

Utilizing the superoxide dismutase activity of ceria nanoparticles to endow poly-l-lactic acid bone implants with antitumor function

Currently, numerous bone tumor patients undergo tumor recurrence after surgical resection, which seriously affects their quality of life. In this study, the ceria (CeO2) nanoparticle was added to Poly-L-Lactic Acid (PLLA) bone implants endowing the bone implant with antitumor function. The results showed that the reactive oxygen species increased in U2OS cells while it dropped in HEK293 cells as the CeO2 content increased. Meanwhile, the PLLA-8CeO2 showed a high cell inhibition rate of 53.66 % for U2OS cells and possessed a high cell viability of 76.96 ± 2.20 % for HEK293 cells, meaning that the implant could kill bone tumor cells meanwhile show good cytocompatibility for normal cells. These were mainly due to the fact that the CeO2 nanoparticles acted as a superoxide dismutase in tumor cells reducing superoxide to hydrogen peroxide, inducing an increase in reactive oxygen species levels. The excess reactive oxygen species could result in tumor cell apoptosis by disrupting mitochondrial structure, oxidizing proteins, and promoting DNA denaturation. Moreover, the compressive strength of PLLA was improved by the CeO2 addition due to its particle dispersion strengthening. Besides, the PLLA-CeO2 had a faster degradation rate compared to PLLA. Overall, the PLLA-CeO2 is a promising implant material for bone tumor treatment.

Effects of La/Mn-Ceria&TiO2 heterojunction on titanium implants: Improved regenerative repair of diabetic bone with enhanced antioxidant characteristics

Hyperglycemia-induced oxidative stress (OS) plays a crucial role in implant osseointegration and often results in implant failure in patients with diabetes. Implants modified with cerium nanoparticles (CeO2-NPs) have gained significant attention owing to their remarkable oxidase-mimetic activity and therapeutic potential. Increasing the Ce3+ content and oxygen vacancy concentration in CeO2-NPs enhances the catalytic activity of CeO2-NPs. In this study, we synthesized lanthanide (La)/manganese (Mn) -doped CeO2-NPs composite coatings (La-CNPs and Mn-CNPs) on alkali-etched Ti substrates using a one-step hydrothermal method. Our findings indicate that the integration of La/Mn doping, in conjunction with a titanium dioxide carrier, augmented both the Ce3+ content and the oxygen vacancy concentration in La-CNPs and Mn-CNPs. By analyzing their electronic energy band structures, we found that La-CNPs exhibited superior catalase activity, whereas Mn-CNPs outperformed them in terms of superoxide dismutase activity. Under OS conditions, La-CNPs and Mn-CNPs (especially Mn-CNPs) markedly reduced intracellular reactive oxygen species levels in MC3T3-E1 cells, promoting their proliferation and osteogenic differentiation. Complementing these in vitro observations, in vivo trials underscored the capability of Mn-CNPs to enhance osteointegration in surrounding implants in diabetic rat models. Consequently, Mn-CNPs coatings present a promising avenue for augmenting the efficacy of implant therapies, especially in patients with diabetes.