An electrochemical sensor based on CS-MWCNT and AuNPs for the detection of mycophenolic acid in plasma.

For patients receiving organ transplants, monitoring the blood concentration of MPA can provide timely information on whether MPA has reached the effective therapeutic window to better function while reducing the incidence of rejection or adverse reactions. In this study, an electrochemical sensor for the detection of MPA was built using a nanocomposite made of CS-MWCNT and AuNPs. At the same time, the high performance liquid phase (HPLC) method for MPA was established and compared with this sensor. The surface morphology, structure, and roughness of the material on the electrode were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and atomic force microscopy (AFM). In addition, the electrochemical behavior of the modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The standard curve was obtained in blank plasma, not pure buffer solution. The peak current was linearly related to the MPA concentration in the linear range of 0.001-0.1 mM with a detection limit of 0.05 µM and good anti-interference ability. Moreover, the sensor was employed with success for the determination of MPA in rat plasma with good recovery. The electrochemical sensor presented here is eco-friendly, and sensitive, and offers a great possibility for practical applicability.

Effect of river-lake connectivity on ecological stoichiometry of lake and carbon storage status in Eastern Plain, China.

C, N, and P in lake sediment are the basis of material and energy cycle, reflecting the economic development, ecological function, and environmental effect. Current research on the effect of lake eutrophication on carbon storage and the river-lake connectivity on nutrient diffusion is lack. This work investigated the accumulation, distribution, correlations, and stoichiometric ratios of C, N, and P of 82 lakes (≥ 10 km2) in Eastern China, analyzed the nutrient limitation, sediment carbon sink, and effect of river-lake connectivity, and discussed the relationships between eutrophication and sediment carbon storage. The average concentrations and ranges of total C, N, and P in lake sediments were (23.26 mg/g, 0.08-153.45 mg/g), (2.32 mg/g, 0.29-14.17 mg/g), and (0.86 mg/g, 0.23-2.64 mg/g), respectively. The ecological stoichiometry of C: N: P in lake sediments was 32: 3.2: 1. P can be easily accumulated in lakes connected from the Yangtze River, while C and N can be easily accumulated in disconnected lakes. The soil-water erosion in runoff is an important factor for P diffusion. The C/N and C/N/P weren't affected by the river-lake connectivity but depended on the plant type. The Eastern Plain Lake Region of China is C and N co-depletion, and P enrichment. The lake eutrophication leading to algal bloom is unfavorable to the goal of carbon storage and carbon neutrality. Outcome of this study will provide a significant reference and strategies for carbon sequestration research, eco-environmental protection, and watershed nutrient management.

Multi-media distribution and risk assessment of per- and polyfluoroalkyl substances in the Huai River Basin, China.

The widespread existence, environmental persistence, and risks of per- and polyfluoroalkyl substances (PFASs) have attracted widespread attention. Herein, the distribution and risk assessment of PFASs were investigated from the Huai River Basin. The ranges in different media were 29.83-217.96 (average of 75.82 ± 35.64 ng/L) in water, 0.17-9.55 ng/g (2.56 ± 2.83 ng/g) in sediments, and 0.21-9.76 ng/g (3.43 ± 3.07 ng/g) in biota. Perfluoropentanoic acid (PFPeA) was the most prevalent PFAS in surface water, followed by perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA), accounted for 42.62 %, 22.23 % and 17.72 % of the total concentrations of the PFASs analyzed, respectively. PFBA was dominant in sediments, accounting for 60.37 % of the total concentrations of the PFASs analyzed. Perfluorooctane sulfonate (PFOS) was the main pollutant in biota, and the highest concentration (5.09 ng/g) was found in Channa argus. Considering the measured concentrations in water, sediments and biota, the sediment-water partition coefficients (log Kd) and bioaccumulation factors (BAF) of PFASs were determined. The log Kd of the PFASs differed among those with a different carbon chain length, C7-C11 PFASs were more likely to be adsorbed onto sediments as the carbon chain length increases, and PFUnDA and PFDA showed the higher BAF value in Channa argus. PFASs in the Huai River Basin posed an acceptable ecological risk, and long-chain PFAS contamination provided green algae with a higher potential ecological risk. Compared to drinking water, aquatic products constituted a higher PFASs threat to human health, especially for children. The highest HQ was found in PFOS, with an HQmax of 0.97-4.32. Residents in the Huai River Basin should reduce their intake of Channa argus, Coilia nasus, and Carassius auratus, children aged 2 to 4 are limited to consuming no more than 6.9 g/d, 9.7 g/d, and 16.6 g/d, respectively.

Development and Validation of a New High-Performance Liquid Chromatography-Ultraviolet Assay for Quantification of Mitoxantrone in Plasma of BALB/c-nu Mice.

The concentration of mitoxantrone in the blood of mice was determined by a high-performance liquid chromatography-ultraviolet method with aloe-emodin as the internal standard. The separation was performed on a Hypersil BDS2 column (4.6 × 250 mm, 5 µm) as the analytical column, the mobile Phase A was acetonitrile, and B was 20-mM potassium dihydrogen phosphate (adding 1% triethylamine and adjusting the pH to 2.8 with phosphoric acid) and 4.6-mM sodium octyl sulfonate. The flow rate was 1.0 mL·min-1, the detection wavelength was 243 nm, the column temperature is 25 ± 5°C and the injection amount was 20 µL. Finally, the linear range of mitoxantrone was 5-200 µg·mL-1, and the correlation coefficient was r = 0.9999. The recovery rate of the method was 91.93-105.5%, and the extraction recovery rate was 91.45-105.5%. The intraday precision and interday precision were <3.29% (limit of detection = 0.3 µg·mL-1). The HPLC method established in this paper was simple, rapid, sensitive and accurate, and can be used to determine the content of mitoxantrone in mouse plasma after tail vein injection.

Aging properties and cadmium remediation mechanism of biochar in sediment from phosphorus-rich water.

Cadmium (Cd) is the main heavy metal pollutant in sediments from East China. The biochar-sediment nexus can provide carbon sequestration and pollution control. In this work, an in situ study was conducted to investigate the long-term effects and control mechanism of biochar and the effect of biochar aging on Cd stabilization in overlying water-pore water-sediment. The Cd2+ concentration in the overlying water was positively correlated with total nitrogen (0.960, P < 0.05), total organic carbon (0.983, P < 0.05), and total phosphorus (0.993, P < 0.01) in pore water. Biochar stabilized Cd2+ by increasing the pH and oxidation-reduction potential of the sediment environment and promoting the formation of Cd1.25Ca0.75(P2O7) on the biochar surface in sediment from phosphorus-rich water. These changes were closely related to the Brunauer-Emmett-Teller surface area and average pore size of the biochar. Within 60 days, the biochar in the sediment underwent aging, which was closely related to the preparation temperature of the biochar. The organic composition of biochar prepared at a low temperature (≤ 300 °C) and the surface structure of biochar prepared at a high temperature (≥ 500 °C) were altered. The biochar parameter changes were in the order of pore volume > Brunauer-Emmett-Teller surface area > pore size. Our results show that biochar modification can enhance the remediation capacity of biochar, but may be unfavorable to biochar anti-aging. This knowledge will support policymakers and researchers when exploring long-term biochar use in contamination control and strengthen future research.

An up-conversion fluorescence lateral-flow immunoassay for rapid detection of Daratumumab in serum protein electrophoresis clinical samples.

BACKGROUND: Daratumumab (DARA) is a commonly used monoclonal antibody (mAb) drug for the treatment of multiple myeloma (MM). Its appearance as a visible abnormal band in the γ-region of a serum protein electrophoresis (SPEP) gel may interfere with the SPEP result interpretation. With the advantages of portability and rapid testing capabilities, up-conversion fluorescence lateral-flow immunoassay (LFA) can be an ideal solution to detect DARA interference. METHODS: An up-conversion fluorescence LFA strip was designed and constructed to perform semi-quantitative DARA testing in clinical samples. The LFA strip test was evaluated for limit of detection (LOD), dynamic range, and analytical interference. RESULTS: To demonstrate the clinical utility of the LFA strip, 43 SPEP-positive patient serum samples were tested for the presence of DARA, and the results exactly matched the DARA usage history in patient medical records. CONCLUSIONS: The performance of the up-conversion fluorescence LFA strip meets the purpose of clarifying DARA interference in SPEP results. It may be used as an independent and objective confirmation of the presence of DARA in clinical samples. The LFA strip offers a cost-effective rapid on-site test to check for DARA interference alongside standard SPEP equipment, which significantly improves the interpretation of ambiguous SPEP results involving DARA, and does not intervene the current SPEP workflow in clinical laboratory practice.

Understanding the Role of Low-Dose Polystyrene Microplastic in Copper Toxicity to Rice Seed (Oryza sativa L.).

There is still much to learn with respect to the potential for microplastics (MPs) to interact with environmental toxins and biota. In the present study, we investigated the effect of MPs on the toxicity of copper (Cu) to rice seeds (Oryza sativa L.). The 7-day median effective concentration (EC50) value of MPs on rice seed germination was 864 mg/L (95% confidence interval [CI] 839 to 897 mg/L). We found that MPs slightly reduced Cu toxicity to rice seeds. The 7-day EC50 of Cu on rice seed germination increased from 7.29 mg/L (95% CI 7.10-7.52 mg/L) to 7.93 mg/L (95% CI 7.58-8.08 mg/L) in the presence of 20 mg/L MPs. We examined this toxicity reduction phenomenon by investigating the role of MPs in the process of Cu transport, Cu accumulation, and metabolic responses. Further investigation found that the MPs used in the present study hardly adsorbed Cu, but these MPs accumulated on the coats of rice seeds and significantly reduced Cu accumulation in rice seedlings. When Cu concentration was 10 mg/L, the presence of MPs reduced the accumulation of Cu in rice seedlings by 34%. We also found that, compared with only Cu present, the addition of MPs resulted in lower reactive oxygen species accumulation and higher catalase activity and glutathione levels in rice seedlings, which also contributed to Cu toxicity reduction. Collectively, the present study shows that polystyrene MPs have the potential to form associations with plant structures which can ultimately impact heavy metal bioaccessibility and therefore toxicity. Environ Toxicol Chem 2024;43:1870-1879. © 2024 SETAC.

A semi-quantitative upconversion nanoparticle-based immunochromatographic assay for SARS-CoV-2 antigen detection.

The unprecedented public health and economic impact of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been met with an equally unprecedented scientific response. Sensitive point-of-care methods to detect SARS-CoV-2 antigens in clinical specimens are urgently required for the rapid screening of individuals with viral infection. Here, we developed an upconversion nanoparticle-based lateral flow immunochromatographic assay (UCNP-LFIA) for the high-sensitivity detection of SARS-CoV-2 nucleocapsid (N) protein. A pair of rabbit SARS-CoV-2 N-specific monoclonal antibodies was conjugated to UCNPs, and the prepared UCNPs were then deposited into the LFIA test strips for detecting and capturing the N protein. Under the test conditions, the limit of detection (LOD) of UCNP-LFIA for the N protein was 3.59 pg/mL, with a linear range of 0.01-100 ng/mL. Compared with that of the current colloidal gold-based LFIA strips, the LOD of the UCNP-LFIA-based method was increased by 100-fold. The antigen recovery rate of the developed method in the simulated pharyngeal swab samples ranged from 91.1 to 117.3%. Furthermore, compared with the reverse transcription-polymerase chain reaction, the developed UCNP-LFIA method showed a sensitivity of 94.73% for 19 patients with COVID-19. Thus, the newly established platform could serve as a promising and convenient fluorescent immunological sensing approach for the efficient screening and diagnosis of COVID-19.

Multiple Risk Assessment of Heavy Metals in Surface Water and Sediment in Taihu Lake, China.

Taihu Lake is the third-largest freshwater lake in eastern China. The contamination of heavy metals (HMs) in Taihu Lake resulting from rapid economic development and population growth has raised significant concerns in recent years. In this study, the contents and spatial distributions of eight typical HMs (Hg, Cr(VI), As, Cd, Cu, Ni, Pb, and Zn) in the fresh surface water and sediments from Taihu Lake were investigated. The potential ecological and health risks posed by HMs were evaluated using multiple assessment methods. Risk quotients were used to assess the ecological risks of HMs, and chronic risk quotients of Cu, Ni, and Pb (>1.0) were found in the surface water of Taihu Lake. According to the geo-accumulation index (Igeo) and pollution load index (PLI) values, the lake sediments exhibited moderate risks of Cd and Hg. In general, the sediments were moderately contaminated by HMs based on the average risk index (RI < 300). Spatially, a high ecological risk posed by the HMs existed in the sediments of northern Taihu Lake (RI > 300), while the sediments in the southwestern and eastern regions had moderate risk levels. The non-carcinogenic risk levels of Hg, Cd, Cu, and Zn were acceptable based on the exposure characteristics of residents living around Taihu Lake. The carcinogenic risk levels of Cr(VI), As, Pb, and Ni through drinking water were acceptable. However, the ingestion of Cr(VI), As, and Ni through drinking water and fish consumption may pose certain health risks. Therefore, the levels of toxic metals, in particular, Cr(VI), As, and Ni, in edible organisms should be monitored periodically and controlled to alleviate the potential carcinogenic risks through food ingestion. Our work provides valuable information concerning the ecological risk distribution of HMs in Taihu Lake, which is essential for protecting the safety of aquatic organisms and human health and minimizing HM pollution in the lake.

Pollution levels and risk assessment of thallium in Chinese surface water and sediments.

Thallium (Tl) is one of the most toxic metals and can cause chronic and acute damage to humans. Due to occurrences of incidents involving Tl pollution in China, its potential environmental impacts are receiving increased attention. However, there is still limited information on Tl concentrations in the environment and their risks to human health and wildlife. This paper provides an overview of the contamination of surface water and sediments by Tl across China and assesses the potential risks using several methods. The acute and chronic aquatic life criteria for Tl were determined to be 13.25 and 1.65 µg/L, respectively. The acute and chronic risk quotients (RQs) of Tl in surface water near mining areas were 0.01-41.51 and 0.20-666.67, respectively, indicating medium to high ecological risks to aquatic organisms. Tl in sediments of Pearl and Gaofeng rivers pose a high risk based on the higher geo-accumulation index (Igeo) and potential ecological risk index (EI) values. Exposure parameters for the Chinese population were used to derive health criteria and assess non-carcinogenic risk posed by Tl in centralized drinking water sources. Tl criteria for protection of human health were calculated to be 0.18 µg/L for water+organisms and 0.30 µg/L for organisms only. The non-carcinogenic risk posed by Tl was acceptable. The human health criteria of Tl for children were the lowest among all age groups. The risks posed by Tl to health of children are greater than those for adults. Therefore, emphasis should be placed on protecting children from exposure to Tl. For the Chinese population, the drinking water guidance value to ensure protection of human health was determined to be 0.44 µg/L. The availability of multiple Tl guidance values for designated water uses will improve the environmental regulation and surveillance of Tl pollution in China and other countries.

Research on the geochemical background values and evolution rules of lake sediments for heavy metals and nutrients in the Eastern China Plain from 1937 to 2017.

For the first time, background quality guidelines have been developed for lake sediments along the Yangtze River. Evolution Rules of watershed environment in Eastern China were analyzed in 1937-2017. These methods of 137Cs and 210Pb radionuclide, 75% cumulative frequency, and background method were applied to calculate the sediment geochemical backgrounds (GB). The average GB values of Cu, Zn, Cd, Pb, Cr, total carbon (TC), total nitrogen (TN) and total phosphorus (TP) are 45.14 mg/kg, 86.99 mg/kg, 0.29 mg/kg, 33.71 mg/kg, 110.90 mg/kg, 17.20 mg/g, 1.60 mg/g, and 665.78 mg/kg, respectively. The radionuclide methods indicated that the sediment rate of 34 cm corresponding to 1963 is 0.63 cm yr-1. The risk and accumulation of the sediment metals and nutrients in Yangtze Plain were uncontaminated levels before 1960, raised since 1980, and increased significantly in 2000. The Cd, TC, and TN in lake sediment were at low to moderate pollution, and few lakes are at high pollution. Sediment background values of the plain are different from soil background values in China and Consensus-Based Sediment Quality Guidelines in Europe/America. Results of sediment quality guidelines provide an important guidance for pollution prevention, environmental management, and risk assessment, especially the formulation of environmental laws.