Peroxide Oxidation Research Articles

Mechanisms of oxidative stress-induced sperm dysfunction

Oxidative stress plays a pivotal role in male infertility by impairing sperm function through various molecular mechanisms. This review explores the impact of excessive reactive oxygen species (ROS) on spermatozoa, particularly focusing on lipid peroxidation, DNA fragmentation, and protein oxidation. Lipid peroxidation damages sperm membranes, reducing fluidity and motility. ROS-induced DNA fragmentation compromises genetic integrity, potentially leading to infertility and adverse offspring outcomes. Protein oxidation alters key structural proteins, impairing sperm motility and the ability to fertilize an egg. The primary sources of oxidative stress in sperm include leukocyte activity, mitochondrial dysfunction, and environmental factors such as smoking and pollution. Despite the presence of natural antioxidant defenses, spermatozoa are particularly vulnerable due to limited repair mechanisms. The review highlights the importance of early intervention through antioxidant therapies and lifestyle changes to mitigate the detrimental effects of oxidative stress on male fertility. Further research is essential to enhance therapeutic approaches and improve reproductive outcomes.

Dual action of non-metal doped C2N and Ti3C2T2 heterojunction enhances the catalytic activity of electrochemical simultaneous oxidation of hydrogen peroxide and peroxymonosulfate:A theoretical study.

Electrochemical advanced oxidation processes (EAOPs) are energy-efficient methods for generating activated radicals like HO• and SO4•-, which enable the degradation of difficult-to-mineralize chlorinated organic compounds. This study explored the catalytic activity and reaction mechanism of EAOPs under a dual strategy involving non-metal doped C2N (X@C2N (X = O, F, Si)) and a heterostructured build(X@C2N/Ti3C2T2) using first principles calculation. The non-metal doping and the heterojunction construction can make H2O2 and PMS spontaneously adsorb (Eads< 0), with negative Gibbs free energy for their oxidation to HO• and SO4•-, significantly enhancing catalytic activity. The catalytic activity of the X@C2N catalysts was in the order of O@, F@, and Si@C2N. The loading of Ti3C2T2 improved the stability and activity of the material, while Ti3C2F2 and Ti3C2O2 proved superior as heterojunction carriers compared to Ti3C2(OH)2. Notably, O@C2N/Ti3C2F2 is proved to be an appropriate catalyst for simultaneous hydrogen peroxide (ΔGmax = -0.90 eV) and peroxymonosulfate (ΔGmax = -0.99 eV) oxidation reactions, achieving non-selective generation of oxidants in electrochemistry. 2,4-D can be effectively degraded by surface-generated HO• and SO4•-, with the reactivity of SO4•- towards 2,4-D greater than that of HO•. This research highlights the potential of combining heteroatom doping with heterojunction catalyst formation to enhance EAOPs for environmental remediation.

The paradoxical effects of beneficial bacteria on Solanum lycopersicum under Cd stress.

This study investigated the complex interactions between a novel consortium and tomato seedlings under cadmium (Cd) stress. The consortium consists of two bacteria, Pseudomonas sp. HS4 and Paenarthrobacter sp. AS8, both with proven plant growth-promoting (PGP) properties, isolated from Cd hyperaccumulators. Our research highlights the paradoxical effects of these bacteria, revealing their dual role in reducing Cd uptake while simultaneously inducing oxidative stress in plants. Hydroponic experiments showed that the consortium reduced Cd accumulation in tomato shoots by 52% compared to uninoculated controls. However, this reduction was accompanied by decreased plant biomass and increased oxidative stress, with malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels up to 80% and 160% higher, respectively, in inoculated plants. Root H₂O₂ production increased by 38% under 50μM Cd without a corresponding rise in catalase (CAT) activity. Despite Cd exposure, the consortium promoted chlorophyll and carotenoid synthesis, restoring pigment levels to those of unstressed controls. Gene expression analysis revealed a complex impact on stress responses, with inoculation suppressing Sl1 gene expression in roots and upregulating the oxidative stress-related GR-1 gene in shoots. These findings highlight the complex and multifaceted relationship between beneficial bacteria and plant fitness under heavy metal stress, with significant implications for sustainable agriculture. The study raises new questions regarding the broader physiological and ecological impacts of applying hyperaccumulator-associated bacteria in crop management, emphasizing the necessity for deeper mechanistic insights into these interactions to fully harness their potential in improving crop resilience and productivity.

Mesoporous Co-Mn ferrites as highly radical-forming catalysts for wet peroxide oxidation of 4-nitrophenol

Mesoporous Co-Mn ferrites as highly radical-forming catalysts for wet peroxide oxidation of 4-nitrophenol

Rapid and effective removal of 2,4-dichlorophenol by peroxidase from potato

ABSTRACT Phenolic compounds discharged in environmental water are required to remove as soon as possible by using the effective methods such as peroxidase catalyzed oxidation to avoid harm to human health. The crude peroxidase is sectionally salted out of potato starch processing wastewater by 40-70% saturated ammonium sulphate, and used to catalyze oxidation of 2,4-dichlorophenol by hydrogen peroxide. Results show that the potato peroxidase has a fine catalytic effect on the oxidation of hydrogen peroxide at 20–50 ℃ and pH 3–10. In just 10 min, 98% of phenol compound can be effectively removed from 1 mL of reaction system containing 1.0 mmol/L 2,4-dichlorophenol, 1.2 mmol/L H2O2 and 50 U/mL peroxidase at pH 6. Obviously, this peroxidase catalyzed oxidation is a green, rapid and effective way, having great potential for removing 2-4-dichlorophenol from polluted water bodies.

Bibliometric analysis and research progress on hydrogen peroxide and persulfate oxidation processes in the remediation of actual oil-contaminated soil.

Oil pollution poses significant harm to both the ecological environment and human health. The primary sources of oil pollutants in soil are leaks that occur during the extraction, transportation, and production phases. In the face of the severe situation of global soil pollution, chemical oxidation technology has shown potential in the remediation of oil-contaminated soil. However, most current research on chemical oxidation technology remains in the laboratory stage, with limited discussion on its characteristics and application conditions in the actual treatment of oil-contaminated sites. To address this gap, this paper applies bibliometric methods to analyze the development trends of chemical oxidation technology and provides a comprehensive review from the perspective of its real-world applications in remediating oil-contaminated soil. It explores commonly used activators, enhancement measures, and key influencing factors of advanced oxidation processes, focusing particularly on those based on hydrogen peroxide and persulfate. The study highlights significant advantages, such as improving remediation efficiency, reducing treatment time, and compatibility with other remediation methods. Nevertheless, challenges remain, including soil acidification, limited pollutant targeting, and high operational costs. To address these issues, this paper proposes innovative directions such as the development of green and efficient activators, optimization of oxidant application strategies, and integration of chemical oxidation with other remediation technologies. These findings aim to establish a robust theoretical foundation and provide strong technical support for future chemical oxidation treatments of such soils. Through this research, we aspire to develop more scientific and effective strategies and methods for the remediation of oil-contaminated soil.

Microplastics in rivers of Gujarat (India) until the Arabian Sea: assessment of the sources, distribution and associated environmental risk.

Microplastics (MPs) have become a notable concern and are released into the environment through the disposal or fragmentation of large plastics. Rivers have been the major pathways for MPs present in the oceans, which significantly affects the marine environment. In the current study, water samples were collected from the upper stream and downstream of Damanganga and Tapi rivers across different sites in the state of Gujarat, India for exploration of MPs contamination. Additionally, samples were also collected from Dumas Beach to detect the presence of MPs. MPs were extracted from the samples through sieving, density separation and wet peroxide oxidation (WPO) techniques which were subsequently analyzed using μ-FTIR, optical microscope, Pyrolysis GCMS (Py-GCMS) and SEM. The concentration of MPs was also quantified from each stretch of Damanganga, Tapi rivers as well as Dumas Beach. Findings revealed that Damanganga showed a higher concentration (3.53 particles/L) of MPs as compared to others. Further, optical microscope and μ-FTIR analysis confirm the presence of MPs like Polypropylene (PP), Polystyrene (PS), Polyethylene terephthalate (PET), Polyethylene (PE) and Polymethyl Methacrylate (PMMA). Pyrolysis products of PP, PS and Polyamide (PA) were detected from Py-GCMS studies. Additionally, SEM images revealed that MPs were subjected to weathering, oxidation and atmospheric deposition over the years. The study additionally confirmed the flux of MPs in both the rivers and beach due to anthropogenic and industrial effects. Risk assessment of MPs was performed using the Pollutant Loading Index (PLI), which indicated that the overall MPs pollution in the studied sites was marginal. Nevertheless, the PLI scores revealed that Damanganga was the most prone to MP pollution among the three study sites.

Bioassays to Assess the Safety of Potassium and Sodium Nitrates and Nitrites

(1) Background: Advances in food processing practices and health care are some of the most significant advances in modern daily life. The goal of this study is to evaluate the safety of potassium and sodium nitrates and nitrites when they are used as fertilizers in agriculture and food additives, as well as the known conversion of nitrate to nitrite in humans. (2) Methods: Various bioassays were conducted to investigate the effects of nitrates and nitrites in the Drosophila melanogaster genetic tester system. These assays focused on the modulation of degenerative processes at the molecular, cellular, individual, and population levels. Additionally, we assessed the chemopreventive potential and the ability to induce DNA strand breaks in HL-60 tumour cells. (3) Results: All nitrate and nitrite concentrations tested were shown to not be toxic or genotoxic in Drosophila since none of the compounds reached the LD50 and significant genetic mutation. A positive or null protective capacity against a toxic agent was found for nitrates, not for nitrites, showing that sodium nitrite has a synergistic effect when combined with the oxidant toxin hydrogen peroxide; and a nutraceutical potential in the lifespan only for sodium nitrate to improve the quality of life in 5 days at ADI concentration. The in vitro results in human leukemia cells showed a chemopreventive potential only for potassium nitrate and sodium nitrite due to reducing the viability of HL-60 cells growth to 18% and 29%, respectively, compared to the controls at ADI (acceptable daily intake) concentrations. However, neither of these showed DNA damage or methylation modifications. (4) Conclusions: The tested compounds were shown to be safe to use during in vivo and in vitro tests when used at the extrapolated ADI concentrations.

Critical review on development of methylene blue degradation by wet catalytic methods

Abstract The development of textile, agriculture, and other related industries has increased the risk of excessive methylene blue (MB) emissions, making efficient treatment of MB an urgent issue in terms of the economy and environment. The most commonly used chemical treatment methods were wet catalytic methods, including catalytic wet air oxidation (CWAO), catalytic wet peroxide oxidation (CWPO), and photocatalysis. CWAO and CWPO both show fast reaction rates and are environmentally friendly. CWAO uses air as an oxidant at a relatively low cost and can effectively solve the leaching problem of the catalyst. CWPO employs inorganic peroxides like hydrogen peroxide (H2O2) as oxidants to form radicals, showing high efficiency. Photocatalytic degradation utilizes light energy to transform pollutants into harmless molecules with fast kinetic. The selection and application of different methods are analyzed basing on the balance among cost, scale, and efficiency. Finally, the perspective of the effective removal of MB is summarized, containing multiple method combinations, catalyst synthesis optimization, and practical application with less side reaction and instrument loss. More promising technology should be considered in the future for better degradation of MB in the industrial field.

Hydrogen-Bonded Di(hydroperoxy)alkane Adducts of the Type Cy3P=O·(HOO)2CHR (R = Alkyl).

Five representatives of a novel type of di(hydroperoxy)alkane adducts of phosphine oxides have been synthesized and fully characterized, including their solubility in organic solvents. The phosphine oxide Cy3PO (1) has been used in combination with the corresponding aldehydes to create the adducts Cy3PO·(HOO)2CHCH3 (2), Cy3PO·(HOO)2CHCH2CH3 (3), Cy3PO·(HOO)2CH(CH2)2CH3 (4), Cy3PO·(HOO)2CH(CH2)3CH3 (5), and Cy3PO·(HOO)2CH(CH2)7CH3 (6). All adducts crystallize easily and contain the peroxide and phosphine oxide hydrogen-bonded in 1:1 ratios. The single crystal X-ray structures of 2-6 and their unique features are discussed. The 31P NMR spectra of the adducts 2-6 show downfield-shifted signals as compared to Cy3PO. In the IR spectra, the ν(P=O) wavenumbers of the adducts have smaller values than the neat phosphine oxide. All spectroscopic results of 2-6 show that the P=O bond is weakened by hydrogen-bonding to the di(hydroperoxy)alkane moieties. Adduct 6 selectively oxidizes PPh3 to OPPh3 within minutes, and nonanal is reformed in the process. The easy synthesis, handling, and administration of these stable, solid, and soluble peroxides with well-defined composition will have a positive impact on synthetic chemistry.

Quantification of microplastics in biowastes including biosolids, compost, and vermicompost destined for land application

The land application of biowastes, including biosolids and compost, is a significant source of microplastics (MP) to terrestrial environments, yet global data on contamination levels are limited. We determined the concentrations of microplastics in biowastes destined for land application in Aotearoa New Zealand. Microplastics were extracted from biosolids, vermicompost, bulk compost, and bagged compost via wet peroxide oxidation digestion and density separations using a modified sediment-microplastics isolation (SMI) unit. The polymer type of each suspected microplastic was confirmed by micro-Fourier-transform infrared (µ-FTIR) spectroscopy, with a minimum detection size of 18 µm. Microplastic concentrations &gt; 0.48 MP/g were identified in every sample, with the highest average abundances in biosolids (2.71 MP/g) and vermicompost (2.69 MP/g), followed by bulk compost (1.94 MP/g) and bagged compost (1.1 MP/g). Fragments (62.7%) were the most frequently detected microplastic morphotype, followed by films (24.7%), fibers (12.2%), and beads (0.4%). Common polymers detected were polypropylene (37.9%), polyethylene (28.6%), and polymethyl methacrylate (PMMA) (11.7%). Identifiable morphotypes included polyurethane foam sponge fragments, polyethylene terephthalate glitter, and PMMA multicolored films. Biodegradable polymers were identified, and their presence in mature compost suggests that compost facilities were unable to provide optimal conditions to support the complete biodegradation of polymers. Annual microplastic contamination in soils from the application of biowaste amendments is projected to be between 1.10 × 107 to 2.71 × 107 MP/ha. The product origin of most microplastics could not be identified, highlighting the ubiquity of microplastics and the urgent need to reduce plastic at the source to reduce instances of pollution in valuable biowastes.

Scanning electrochemical probe microscopy: towards the characterization of micro- and nanostructured photocatalytic materials.

Platinum-black (Pt-B) has been demonstrated to be an excellent electrocatalytic material for the electrochemical oxidation of hydrogen peroxide (H2O2). As Pt-B films can be deposited electrochemically, micro- and nano-sized conductive transducers can be modified with Pt-B. Here, we present the potential of Pt-B micro- and sub-micro-sized sensors for the detection and quantification of hydrogen (H2) in solution. Using these microsensors, no sampling step for H2 determination is required and e.g., in photocatalysis, the onset of H2 evolution can be monitored in situ. We present Pt-B-based H2 micro- and sub-micro-sized sensors based on different electrochemical transducers such as microelectrodes and atomic force microscopy (AFM)-scanning electrochemical microscopy (SECM) probes, which enable local measurements e.g., at heterogenized photocatalytically active samples. The microsensors are characterized in terms of limits of detection (LOD), which ranges from 4.0 μM to 30 μM depending on the size of the sensors and the experimental conditions such as type of electrolyte and pH. The sensors were tested for the in situ H2 evolution by light-driven water-splitting, i.e., using ascorbic acid or triethanolamine solutions, showing a wide linear concentration range, good reproducibility, and high sensitivity. Proof-of-principle experiments using Pt-B-modified cantilever-based sensors were performed using a model sample platinum substrate to map the electrochemical H2 evolution along with the topography using AFM-SECM.

A covalent organic framework-based nanoreactor for enhanced chemodynamic therapy through cascaded Fenton-like reactions and nitric oxide delivery.

Herein, we report a nanoscale composite COF material loaded with copper peroxide (CuO2) and nitric oxide (NO) prodrug via a stepwise post-synthetic modification. The obtained CuO2@COF-SNO can undergo a cascade reaction in the tumor microenvironment to generate reactive oxygen and nitrogen species (ROS/RNS) to enhance chemodynamic therapy of the tumor.

Evaluation of Xanthine Oxidase Inhibitors Febuxostat and Allopurinol on Kidney Dysfunction and Histological Damage in Two-Kidney, One-Clip (2K1C) Rats.

In chronic kidney disease (CKD), hyperuricemia is a common phenomenon, presumably due to reduced renal clearance of uric acid. This study investigated the effect of xanthine oxidase (XO) inhibitors allopurinol and febuxostat to prevent oxidative stress in the kidney of two-kidney, one-clip (2K1C) rats. In this investigation, 2K1C rats were used as an experimental animal model for kidney dysfunction. 2K1C rats were provided with food and drinking water and received febuxostat at a dose of 10 mg/kg or allopurinol at 100 mg/kg, respectively. After the treatment completion, all rats were sacrificed, and tissue samples were collected. 2K1C rats exhibited increased plasma creatinine, uric acid level, and glomerular injury assessed based on microscopic findings. Both allopurinol and febuxostat significantly normalized creatinine and uric acid levels. Furthermore, 2K1C rats showed increased lipid peroxidation (LPO), nitric oxide (NO), and advanced oxidation protein products (AOPP) alongside decreased superoxide dismutase (SOD) and catalase activity. Again, both drug treatments ameliorated these elevated oxidative stress parameters in 2K1C rats. The antioxidant genes such as Nrf-2, HO-1, and SOD were also restored in the kidneys of 2K1C rats by allopurinol and febuxostat treatment. 2K1C rats also showed increased IL-1β, IL-6, TNF-α, and NF-кB mRNA expression in the kidneys which were normalized by allopurinol and febuxostat treatment. Thus, the data suggest that XO inhibition protects kidney function potentially by restoring antioxidant enzyme function and suppressing inflammation.

Continuous-flow synthesis of carboxylic acids from alcohols via platinum and silicon dioxide-catalyzed hydrogen peroxide oxidation.

A continuous-flow method for the direct oxidation of alcohols to carboxylic acids is reported, employing hydrogen peroxide (H2O2) and a platinum (Pt) catalyst within a flow reactor system. This approach allows for precise control over the contact time between the reactants and the catalyst, enabling optimization of reaction conditions. By analyzing the yields of both aldehydes and carboxylic acids as a function of weight hourly space velocity (WHSV), selective synthesis of carboxylic acids was achieved without the formation of corresponding aldehydes. The Pt catalyst exhibited excellent stability, producing 25.2 g of octanoic acid from 1-octanol with a yield exceeding 96% over 210 h at a WHSV of 1.3 h-1 using a 5 mm inner diameter × 100 mm column. This Pt-catalyzed continuous-flow H2O2 oxidation method demonstrates good reactivity for a variety of alcohols, including aliphatic, aromatic, allylic, and heteroaromatic, affording the corresponding carboxylic acids in 19-98% isolated yields with water as the sole byproduct. X-ray photoelectron spectroscopy (XPS) analysis confirmed the preservation of metallic zero-valent Pt (Pt(0)) throughout the reaction.

Do Fe2O3/TiO2 heterojunctions improve the wastewater disinfection process?

This work examines the photocatalytic capacity of Fe2O3-TiO2 catalysts for inactivating Enterococcus faecalis in water and compares it to a peroxide-assisted process. The influence of H2O2, PMS, pH, and temperature is assessed. Material stability and free radical species involved in disinfection are also evaluated. The main findings indicate that Fe2O3-TiO2 photocatalysts do not improve disinfection results compared to mesoporous TiO2, achieving total disinfection after 90min. Using PMS and H2O2 as oxidants in Catalytic Wet Peroxide Oxidation, system 0.15mM PMS/0.5g/L mTiO2 under solar radiation reduced the required time to 10min for total bacterial inactivation (extended to 30min with diclofenac present due to competition for radicals), whereas H2O2 took approximately 70min. The Fe2O3-TiO2 heterojunction catalysts (Cat2 - Cat5) showed no improvement, likely due to bacteria-photocatalyst interactions preventing oxidants from reacting with Fe on the catalyst surface. EPR analyses revealed hydroxyl radicals as the predominant oxidizing species (over 90% abundance). Additionally, higher pH values (>6) decreased inactivation kinetics, while increasing the temperature to 40°C improved it by up to 120%. The photocatalyst showed low stability from the fourth use, with a 40% decrease in bacterial inactivation kinetics.

Microplastics contamination in Coban Kethak and its flow

This study aims to identify the distribution and frequency of microplastics in the sediment and water of Coban Kethak, a water source in the Malang, Indonesia. Recreation, recreation with sanitary facilities, durian plantation, and paddy fields were the four sites from where samples were taken, and each represented a distinct set of human-caused features. Wet peroxide oxidation and density separation procedures were used to extract microplastics, which were seen and identified using stereomicroscopy. PCA and clustering were analyzed using PAST software to identify the main patterns of variation in microplastic density among locations. This study found that microplastics, all smaller than 3 μm in size, were found in four different shapes: fibers, pieces, films, and microbeads. Microplastic concentrations in sediment (84 particles/100g) and water (68 particles/50L) were highest at the recreational location and lowest in the paddy field region (0 microplastic in sediment sample and 44 particles/50L in water sample, respectively). According to principal component analysis and cluster analysis, the study shows that microplastic contamination is associated with human activities, with recreational areas being the most affected. According to these findings, further study and targeted solutions are needed to decrease microplastic contamination in freshwater ecosystems, especially in places with heavy human activity.

Preliminary study on the potential damage of cigarette smoke extract in 3D human chondrocyte culture.

Osteoarthritis (OA) is a chronic degenerative disease characterized by the progressive loss of articular cartilage. The role of cigarette smoke (CS) in OA is debated, with some studies suggesting a protective effect while others indicate it may pose a risk. Our preliminary findings suggest a link between smoking in young adults and severe knee OA, though the extent of this contribution is unclear. This study investigates the impact of cigarette smoke extract (CSE) on human chondrocytes. Human chondrocyte cultures were exposed to varying concentrations (0-10%) of CSE for 7 d. We evaluated cell viability, extracellular matrix (ECM) components, metalloproteinaseexpression and cytokines levels, and antioxidant enzymes (SOD1 and CAT) using calcein staining, immunohistochemistry and ELISA. Oxidative stress (OS) was assessed by measuring hydrogen peroxide (H2O2) and nitric oxide (NO) levels. Results were analyzed using ANOVA with Tukey post hoc tests, and Pearson correlation coefficients were calculated. Cell viability decreased at 10% CSE, and ECM components were diminished. MMP9 and MMP13 expression significantly increased at 5% and 10% CSE. H2O2 levels peaked at 1%, while IL-1β peaked at 2.5%. Antioxidant expression (SOD1 and CAT) decreased at higher concentrations, and heat shock protein 70 (HSP70) was notably expressed. MMPs expression was negatively correlated with both viability and ECM components. CSE induces cellular damage, alters ECM composition, and upregulates MMP expression via OS and IL-1β, while diminishing antioxidant defenses. These findings suggest that smoking may disrupt articular cartilage homeostasis, highlighting the need for further investigation into oxidative stress and inflammatory mediators.

Quality and Oxidative Stability of Tallow Extracted by Dry- and Wet-Rendering

The oxidative stability of oil or fats is an essential parameter to determine the quality of products. Commonly, tallow is extracted by dry- and wet-rendering, both methods depend upon the water requirement. The study aims to examine the quality and oxidative stability of tallow from both methods, along with different temperatures (25°C and 4°C) and storage times. Tallow was analyzed for quality changes such as acid value (AV), peroxide value (PV), thiobarbituric acid (TBA), fatty acid profile, and differential scanning calorimetry (DSC) to indicate oxidative stability. According to research, acid value (AV) and thiobarbituric acid (TBA) were considered acceptable during storage for 180 days, as per the Codex Standard and FAO/WHO for Named Animal Fats CODEX STAN 211–1999 for edible fats and oils. However, peroxide oxide value (PV) did not meet the acceptable limit for dry- and wet-rendering and storage time of 180 days at 25°C, with values of 17.3 and 16.9 meq O2/kg, respectively. This indicates that fat oxidation increases during storage (p&lt;0.05), while temperature and rendering methods do not significantly impact fat hydrolysis inhibition for 180 days (p&gt;0.05). Even at 4°C, both temperatures failed to preserve tallow quality, as confirmed by fatty acid profiles and differential scanning calorimetry. The result indicates that neither method nor temperature can prevent the inhibition of fat hydrolysis from natural oxidation for a longer storage time of 180 days.

Polystyrene Nanoplastics Elicit Multiple Responses in Immune Cells of the Eisenia fetida (Savigny, 1826).

The improper disposal of plastic products/wastes can lead to the release of nanoplastics (NPs) into environmental media, especially soil. Nevertheless, their toxicity mechanisms in soil invertebrates remain unclear. This study investigated the impact of polystyrene NPs on Eisenia fetida (Savigny, 1826) immune cells, focusing on oxidative stress, immune responses, apoptosis, and necrosis. Results showed that 100 nm NPs were internalized into the cells, causing cytotoxicity. NPs were observed to inhibit cell viability by increasing reactive oxygen species, decreasing the levels of antioxidants (e.g., superoxide dismutase, catalase, and glutathione), and inducing lipid peroxidation and DNA oxidation. Additionally, assays on neutral red retention time, lysozyme activity, and Ca2⁺ levels demonstrated that NPs resulted in a loss of lysosomal membrane stability and a reduction in immune resistance. The depolarization of the mitochondrial membrane potential and the results of the apoptosis assays confirmed that the NPs induced the onset of early apoptosis. The difficulty of the NP in causing cell death by disrupting the plasma membrane was demonstrated by the results of the lactate dehydrogenase release assays in relation to cell necrosis. This research provides cellular-level insights into the ecological risks of NP exposure on soil fauna.