Neurobehavioral and neurochemical alterations in female mice following pregestational exposure to SARS-CoV-2 lysate protein

The rapid introduction of new environmental contaminants, including viral agents like SARS-CoV-2, has raised concerns about their indirect effects on non-target terrestrial organisms, especially through contaminated water sources. In this study, we investigated the potential neurotoxic effects of pre-mating and gestational exposure to SARS-CoV-2 lysate protein. Female C57Bl/6 J mice were exposed to a concentration of 20 μg/L for 30 days via drinking water. No significant effects were observed on gestational duration, litter size, or offspring biomass, suggesting no direct impact on reproductive performance. However, exposed females exhibited marked neurobehavioral alterations, including increased anxiety-like behavior in the open field test and altered maternal care dynamics, characterized by hyper-responsiveness and increased nest attendance duration. These behavioral changes were strongly correlated with neurochemical imbalances, including elevated dopamine levels in the olfactory bulb, brain, and hypothalamic-pituitary region. Additionally, cholinesterase activity was significantly altered, with increased acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity in the olfactory bulb and brain, but decreased AChE activity in the hypothalamus-pituitary region, suggesting disrupted cholinergic signaling. Furthermore, oxidative and nitrosative stress markers (ROS and NO) were significantly elevated in mammary and ovarian tissues, indicating a persistent inflammatory response even after exposure cessation. These findings highlight long-term neurochemical and behavioral disruptions following environmentally relevant exposure to SARS-CoV-2 lysate protein, which could compromise neurophysiological homeostasis, stress regulation, and maternal investment in non-target mammals. In natural environments, such alterations may reduce individual fitness and population resilience, emphasizing the need to further investigate the ecotoxicological consequences of viral pollutants on terrestrial organisms.

Development of an Electrochemical Biosensor Based on Polypyrrole-3-carboxylic Acid/Polypyrrole/Au Nanoparticle Composites for Detection of Dopamine

Dopamine (DA) is a neurotransmitter that works in the brain. It plays several important roles in executive functions, including motor control, memory, mood, motivation, and reward. DA imbalances are associated with diseases in the nervous system such as Parkinson's disease, schizophrenia, Alzheimer's disease, and attention deficit hyperactivity disorder (ADHD). Therefore, the development of a biosensor for the detection of precise amounts of DA is of great interest. In this research, polypyrrole-3-carboxylic acid/polypyrrole/gold nanoparticle (PP3C/PPy/AuNPs) composites were developed for the electrochemical detection of DA. Firstly, a PP3C/PPy/AuNPs composite thin film was synthesized by electropolymerization on a fluorine-doped tin oxide (FTO)-coated glass substrate. Subsequently, cyclic voltammetry (CV), scanning electron microscopy (SEM), and differential pulse voltammetry (DPV) were used for the characterization and study of the efficiency of the obtained conducting polymer-gold nanoparticle composite thin film for the detection of DA. The proposed electrochemical sensor showed good sensitivity and selectivity for the detection of DA with a wide detection linear range from 5 to 180 μM (R2 = 0.9913). The limit of detection (LOD) and limit of quantitation (LOQ) values were 9.72 nM and 0.032 μM, respectively. Therefore, it can be concluded that the electrochemically fabricated PP3C/PPy/AuNPs composite thin film can be applied as an electrochemical biosensor for the detection of dopamine for the early diagnosis of various neurological disorders in the future.

Smartphone-assisted fluorescence/colorimetric dual-mode sensing strategy for uranium ion detection using cerium-sulfonyl calix[4]arene

A novel fluorescence/colorimetric dual-mode detection strategy for uranium ions (UO22+) is presented based on a cerium-sulfonyl calix[4]arene (SC4A) platform. The exo- and endo-rim sites of SC4A can coordinate with Ce3+ and Ce4+ ions, respectively, quenching Ce3+ fluorescence and influencing the oxidase-like activity of Ce4+. In the absence of UO22+, the solution of 3,3,5,5-tetramethylbenzidine (TMB) remains blue, but upon UO22+ binding, Ce3+ dissociates from SC4A, restoring fluorescence, while UO22+ interacts with oxTMB, turning the solution from blue to colorless. This dual-mode system provides a linear fluorescence detection range of 30-800 nM with a detection limit of 20.20 nM, and a colorimetric range of 30-800 nM with a detection limit of 27.78 nM. By combining high-sensitivity fluorescence with visual colorimetric analysis, the proposed method possesses high sensitivity, accuracy, and reliability. Notably, smartphone-based color capture facilitates rapid and convenient sample analysis, enabling straightforward quantification at varying UO22+ concentrations. The method has been successfully applied to real water and urine samples, demonstrating its practical utility in environmental and biological monitoring of UO22+.

Necroecological Trophic Transfer of Microplastics: Insights into the Ecotoxicity of Petroleum-Derived and Biodegradable Polymers

Although the toxicity of petroleum-derived microplastics (MPs) has been widely investigated, the impact of biomicroplastics (BioMPs) remains controversial, and the necroecological trophic transfer of both is still poorly understood. Our study reveals that biomicroplastics may pose ecotoxicological risks comparable to or greater than those of petroleum-derived plastics, a finding that should raise concern. We aimed to evaluate the possible translocation of polystyrene (PS) and polylactic acid (PLA) MPs from mice to the necrophagous fly Synthesiomyia nudiseta and their potential effects on the larval stage. Mice were inoculated intraperitoneally with different doses of MPs [9 (I) and 90 mg/kg (II)] and subjected to the decomposition process (for ten days), allowing colonization by larvae. Our results confirmed the translocation of MPs from mice to S. nudiseta larvae, resulting in a greater accumulation of PLA-MPs compared to PS-MPs. We observed that exposure to MPs significantly influenced biomass accumulation, with larvae from the PS-I and PLA-I groups showing increased biomass. In contrast, those from the PLA-II group exhibited lower biomass. AChE activity was modulated in a concentration-dependent manner, with an increase observed in larvae exposed to PLA-MPs, indicating a potential neurotoxic effect. In addition, there was an increased production of reactive oxygen species (ROS), especially in the groups exposed to higher concentrations of MPs, without a proportional response of antioxidant enzymes, suggesting a redox imbalance and oxidative stress. The elevated serotonin levels and reduced dopamine observed in larvae exposed to MPs indicate a possible redirection of energy resources and changes related to a metabolic adaptation to the stress imposed by MPs. Principal component analysis (PCA) showed that PC1 was strongly influenced by biomarkers such as trypsin, chymotrypsin, AChE, ROS, and dopamine activity, highlighting that PLA-MPs (at the highest concentration) induced more pronounced toxic effects than PS-MPs. This finding was corroborated by discriminant analysis, which revealed a clear separation between the experimental groups, and by multiple regression analysis, which confirmed a strong relationship between MP concentration and larval biomarker responses, indicating that the type and concentration of MPs explained approximately 65% ​​of the variation in the biomarkers evaluated. In conclusion, our study demonstrates for the first time the necroecological trophic translocation of MPs between vertebrates and invertebrates, highlighting the potential risks of biomicroplastics.

Beyond the virus: ecotoxicological and reproductive impacts of SARS-CoV-2 lysate protein in C57Bl/6j female mice

Since the establishment of the COVID-19 pandemic, a range of studies have been developed to understand the pathogenesis of SARS-CoV-2 infection, vaccine development, and therapeutic testing. However, the possible impacts that these viruses can have on non-target organisms have been explored little, and our knowledge of the consequences of the COVID-19 pandemic for biota is still very limited. Thus, the current study aimed to address this knowledge gap by evaluating the possible impacts of oral exposure of C57Bl/6 J female mice to SARS-CoV-2 lysate protein (at 20 µg/L) for 30 days, using multiple methods, including behavioral assessments, biochemical analyses, and histopathological examinations. Although we did not have evidence of hematological, mutagenic, or genotoxic effects, we noted that the ingestion of SARS-CoV-2 lysate protein-induced behavioral disorders (hypoactivity, anxiety-like behavior, and short-term memory deficit), which were associated with oxidative stress and dopaminergic and cholinesterase imbalance in the animal brain. Furthermore, the elevation of bilirubin levels and lactate dehydrogenase levels in these animals suggests the occurrence of hepatic changes, and the redox imbalance, nitrosative stress, and elevated production of IFN-γ and inflammatory infiltration in the duodenum, disrupted follicular structure, and presence of vacuoles in granulosa cells, in ovarian, indicate that the SARS-CoV-2-exposed group showed significant toxicity. Principal component analysis (PCA) and cluster analysis confirmed that the groups were clearly separated and showed that the largest changes upon SARS-CoV-2 exposure were related to ROS, MDA, nitrite, IFN-γ/IL-10 levels and SOD and catalase activity in the ovary; IFN-γ/IL-10 production and SOD activity in the duodenum; BChE activity in the brain; bilirubin levels and lactate dehydrogenase activity in the serum; number of primary follicles in the ovary. In conclusion, our study provides new insights into the toxicity of SARS-CoV-2 lysate proteins in a non-target terrestrial organism of infection and, therefore, expands our understanding of the real extent of the ecological/environmental impact of the COVID-19 pandemic.

Nanoplasmonic aptasensor for sensitive, selective, and real-time detection of dopamine from unprocessed whole blood

Neurotransmitters are crucial for the proper functioning of neural systems, with dopamine playing a pivotal role in cognition, emotions, and motor control. Dysregulated dopamine levels are linked to various disorders, underscoring the need for accurate detection in research and diagnostics. Single-stranded DNA (ssDNA) aptamers are promising bioreceptors for dopamine detection due to their selectivity, improved stability, and synthesis feasibility. However, discrepancies in dopamine specificity have presented challenges. Here, we surface-functionalized a nano-plasmonic biosensing platform with a dopamine-specific ssDNA aptamer for selective detection. The biosensor, featuring narrowband hybrid plasmonic resonances, achieves high specificity through functionalization with aptamers and passivation processes. Sensitivity and selectivity for dopamine detection are demonstrated across a wide range of concentrations, including in diverse biological samples like protein solutions, cerebrospinal fluid, and whole blood. These results highlight the potential of plasmonic "aptasensors" for developing rapid and accurate diagnostic tools for disease monitoring, medical diagnostics, and targeted therapies.

Using the High-Entropy Approach to Obtain Multimetal Oxide Nanozymes: Library Synthesis, In Silico Structure-Activity, and Immunoassay Performance

High-entropy nanomaterials exhibit exceptional mechanical, physical, and chemical properties, finding applications in many industries. Peroxidases are metalloenzymes that accelerate the decomposition of hydrogen peroxide. This study uses the high-entropy approach to generate multimetal oxide-based nanozymes with peroxidase-like activity and explores their application as sensors in ex vivo bioassays. A library of 81 materials was produced using a coprecipitation method for rapid synthesis of up to 100 variants in a single plate. The A and B sites of the magnetite structure, (AA')(BB'B'')2O4, were substituted with up to six different cations (Cu/Fe/Zn/Mg/Mn/Cr). Increasing the compositional complexity improved the catalytic performance; however, substitutions of single elements also caused drastic reductions in the peroxidase-like activity. A generalized linear model was developed describing the relationship between material composition and catalytic activity. Binary interactions between elements that acted synergistically or antagonistically were identified, and a single parameter, the mean interaction effect, was observed to correlate highly with catalytic activity, providing a valuable tool for the design of high-entropy-inspired nanozymes.

Fluorometric and colorimetric quantitative analysis platform for acid phosphatase by cerium ions-directed AIE and oxidase-like activity

A facile and sensitive fluorescent and colorimetric dual-readout assay for detection of acid phosphatase (ACP) was developed via Ce(III) ions-directed aggregation-induced emission (AIE) of glutathione-protected gold nanoclusters (GSH-AuNCs) and oxidase-mimicking activity of Ce(IV) ions. Free Ce(IV) ions exhibited a strong oxidase-mimetic activity, catalytically oxidizing colorless 3,3',5,5'-tetramethylbenzidine (TMB) into its blue product oxTMB in the presence of dissolved O2, thus triggering a remarkable color reaction detected visually. ACP can hydrolyze L-ascorbic acid-2-phosphate (AAP) with the production of ascorbic acid (AA). The AA is able to reduce Ce(IV) ions to Ce(III) ions, thus quenching the oxidase-mimetic activity of Ce(IV) ions. Meanwhile, Ce(III) ions induce AIE of GSH-AuNCs, resulting in the enhancement of the fluorescence signal of GSH-AuNCs. Both the fluorescent and colorimetric dual-mode analysis platforms exhibit a sensitive response to ACP, providing detection limits as low as 0.101 U/L and 0.200 U/L, respectively. Besides, this fabricated dual-mode detection platform holds the potential for analysis of ACP in human serum samples and screening inhibitors for ACP. With good performance and practicability, this study shows promising application in the convenient and reliable determination of ACP activity.

Ce(IV)-coordinated organogel-based assay for on-site monitoring of propyl gallate with turn-on fluorescence signal

Propyl gallate (PG) is a commonly used synthetic phenolic antioxidant in foodstuffs and industrial products. Due to the potential health risk of PG, rapid and on-site detection in food and environment samples are important to guarantee human health. Herein, we demonstrated rapid monitoring of PG by a fluorescence turn-on strategy based on a specific fluorogenic reaction between PG and polyethyleneimine (PEI). Specifically, Ce4+ with oxidase-mimicking activity oxidized PG to its oxides, which then reacted with PEI through the Michael addition to generate the fluorescent compound. The proposed fluorogenic reaction had good specificity for PG, which could distinguish PG from other phenolic antioxidants and interferences. Furthermore, portable and low-cost organogel test kits were prepared using poly(ethylene glycol) diacrylate for quantitative and on-site detection of PG via a smartphone-based sensing platform. The organogel-based assay detection limit was 1.0 μg mL-1 with recoveries ranging from 80.2% to 106.2% in edible oils and surface water. Suitability of the developed assay was also validated by high-performance liquid chromatography. Our study provides an effective fluorescent approach to rapid, specific, and convenient monitoring of PG, which is useful for diminishing the risk of PG exposure.

Core-shell Au-Ag nanoparticles as colorimetric sensing probes for highly selective detection of a dopamine neurotransmitter under different pH conditions

Dopamine (DA) is a vital biomarker for the early diagnosis of dopaminergic dysfunction; therefore, it is important to establish a direct and selective detection tool for DA neurotransmitters. This work reports facilely synthesized Au-Ag core-shell nanoparticles (Au@Ag NPs) as colorimetric sensing probes for highly selective detection of the DA neurotransmitter. Our sensing strategy is based on DA-mediated aggregation of the Au@Ag NPs, which can show a distinct color transition from yellow to greenish grey. With the increase of pH from 6 to 10, the response time of colorimetric transition was significantly reduced by a factor of 10 and the limit of detection (LOD) for DA by a spectroscopic device was estimated to be 0.08 μM. Notably, optimized sensing probes of Au@Ag NPs at pH 10 demonstrated an excellent selectivity to DA against various interfering components (including catecholamines (norepinephrine and epinephrine), lysine, glutamic acid, glucose, or metal ions). Our sensing system also exhibited the reliable detection of DA in spiked human serum with the relative standard deviation lower than 4.0%, suggesting its possible application to the direct detection of DA in biological fluids.

Synthesis of Co3O4 Nanoplates by Thermal Decomposition for the Colorimetric Detection of Dopamine

Inorganic nanomaterials with enzyme-like activity have been attracting much attention due to their low cost, favorable stability, convenient storage, and simple preparation. Herein, Co₃O₄ nanoplates with a uniform nanostructure were prepared by the thermolysis of cobalt hydroxide at different temperatures, and the influence of the annealing temperature on the performance of the mimetic enzyme also was reported for the first time. The results demonstrated that Co₃O₄ nanoplates obtained at an annealing temperature of 200 °C possessed strong oxidase activity and efficiently catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) without the addition of hydrogen peroxide to generate the blue color product ox-TMB. Once the annealing temperature was increased to 500 °C and 800 °C, the oxidase activity of Co₃O₄ decreased rapidly, and was even inactivated. This might be attributed to the relatively large specific surface area of Co₃O₄ annealed at 200 °C. Besides this, based on the TMB-Co₃O₄ nanoplate system, a colorimetric analysis method was developed to detect dopamine with a limit of 0.82 μmol/L in a linear range from 1.6 μmol/L to 20 μmol/L.