Concentrations Of Diethylstilbestrol Research Articles

Embedded ZnO nanorod in ZIF-8 as a high-efficiency core–shell structural electrocatalyst for subnanomole level sensing of diethylstilbestrol

In view of the core–shell nanocomposites can complement the functions of the core and shell components, we here demonstrate a facile self-template strategy for synthesizing a one-dimensional rod-like hierarchical ZnO@ZIF-8 core–shell structure composed of a stabilized core and an active shell. The ZnO nanorods not only served as the template, but also as source of Zn ions for the in situ formation of zeolitic imidazolate framework-8 (ZIF-8) crystal shell, and the well-stabilized ZnO core preserved its own nature during the growth of the ZIF-8 shell. Furthermore, a sensing platform using ZnO@ZIF-8 as electrocatalyst was developed, which demonstrated salient electrocatalytic activity for diethylstilbestrol (DES) oxidation. The concentration of DES was directly proportional to its anodic peak current in the range of 2 nmol/L to 2 µmol/L, and ultralow detection limit of 0.73 nmol/L ( S/ N = 3) was achieved. The proposed method also gave excellent selectivity, reproducibility, and stability, showing promising analytical performance for the measurement of DES in food samples of animal origin.

Determination of diethylstilbestrol in environmental water based on electrochemical senser modified with vanadium based metal organic framework material composite

In this research, the MIL-47/ACET/Nafion/GCE electrochemical senser for the determination of diethylstilbestrol (DES) was prepared with vanadyl sulfate (VOSO4·nH2O) and terephthalic acid (H2BDC) as the main raw materials, compounded with acetylene black (ACET) and perfluorosulfonic acid polymer (Nafion). The compound DES belongs to the category of estrogens, and prolonged exposure to the environment can have detrimental effects on the physiological functioning of both humans and animals. Due to the strong DES enrichment performance of MIL-47(V-MOFs) with large specific surface area, in addition to the excellent conductivity and electrocatalysis of composite materials, this modified senser had good electrochemical response to DES. With differential pulse voltammetry, in optimum condition of 0.1 M NaH2PO4–Na2HPO4 at pH = 7.0, potential interval of −1.0 to 1.0 V, enrichment time of 120 s and enrichment potential of 0.2 V, there was a good linear relationship between peak current and the concentration of DES over the range of 0.1 and 50 μM, and the limit of detection was 0.008 μM. The sensor accurately detected DES in actual water samples, with recovery rates ranging from 89.21% to 105.3%. The electrochemical sensor was simple to prepare and had practical significance for the detection of DES in water. The research results of the sensor provide another alternative analytical means for the sensitive detection of DES in the environment, which is important for maintaining public health.

A novel photothermal sensing probe based on violet phosphorus for sensitive immunochromatographic sensing detection

Photothermal immunochromatographic sensor is an emerging detection technology, and it is important to develop new sensing probes with excellent photothermal performance to improve its detection performance. In the present study, a novel photothermal sensing probe based on violet phosphorus nanosheets with satisfactory photothermal conversion efficiency (31.1 %) was reported for the first time. A photothermal immunochromatographic sensor using the above probe was applied for visual and photothermal detection of diethylstilbestrol. The diethylstilbestrol concentration was inversely proportional to photothermal sensing signal and showed a good linear correlation in the range of 0.75 ∼ 50 μg·L−1. After optimizing, the visual and photothermal detection limits were 6 μg·L−1 and 0.56 μg·L−1, respectively. The recovery rates in tap water, milk and pork samples ranged from 82.2 % to 115.2 %, with a coefficient of variation (CV) ranging from 2.0 % to 10.8 %. This work not only structured a new type of photothermal probe, but also expanded the application range of violet phosphorus.

Occurrence and Degradation of Free and Conjugated Estrogens in a River Receiving Feedlot Animal Discharge

This study analyzed concentrations of 17β-estradiol (E2), estrone (E1), estriol (E3), 17α-ethynylestradiol (EE2), diethylstilbestrol (DES), 17β-estradiol-3-sulfate (E2-3S), estrone-3-sulfate (E1-3S), 17β-estradiol-3-glucuronide (E2-3G), and estrone-3-glucuronide (E1-3G) in river water, received from intensive feedlot operations wastewater in WuLo Creek, Taiwan. Moreover, the estrogen degradation in situ was analyzed. The average concentrations were 54.15 ± 31.42, 9.71 ± 6.42 and 3.55 ± 2.41 ng/L for E1, E2 and E3, respectively. The concentrations and order were similar to the polluted river and higher than most rivers’ concentrations. The conjugated estrogen concentrations ranged from ND to 13.2 ng/L (E1-3S), ND to 10.4 ng/L (E2-3S), ND to 10.0 ng/L (E1-3G), and ND to 3.6 ng/L (E2-3G), and the detection rates were 76%, 71%, 56%, and 15%, respectively. In the present study, the high detection rates of conjugate estrogen were more elevated than the water receiving STP effluent, suggesting that the source was the river water close to the animal wastewater discharge. In the degradation test, the DES concentrations slightly declined after 24 h, but E1-3G did not significantly change over time (p > 0.05). The degradation of free estrogen occurred during the first 12 h period, and residual concentration was not further decreased after 24 h. In the environment, E1 had higher concentrations than E2 and E3, suggesting that E1 was more resistant to degradation than E2 and E3 at low concentrations. However, the degradation test in the present study suggested that E1 rapidly degraded at high ambient concentrations due to the high degradation constant.

Determination of Diethylstilbestrol in Environmental Water Based on Co(II)-Sensitized Electrochemical Sensing

In this research, a simple electrochemical sensor (c-MWCNTs/Nafion/GCE) was prepared by carboxylated multi-walled carbon nanotube, perfluorosulfonic acid polymer and glassy carbon electrode using drop coating method, and based on the obvious sensitization effect on the redox peak current of diethylstilbestrol (DES) in the presence of Co2+, a new electrochemical sensing method for the determination of DES in water was established. In a buffered solution of 0.2 mol l−1 NaH2PO4-Na2HPO4 at pH = 7.0, differential pulse voltammetry (DPV) was used when the Co2+ concentration was 20 μmol l−1. Under the optimized conditions of −0.2 ∼ −0.4 V (vs SCE), −0.2 V enrichment potential, and 120 s enrichment time, the concentration of DES showed a good linear relationship with the peak current over the range of 0.3 to 90 μmol l−1, and the detection limit(S/N = 3) was 0.01 μmol l−1. The actual water sample was detected, and the recovery was between 89.17% and 101.23%. This method had the characteristics of simple operation, low analysis cost and fast analysis speed, and had the potential application value of detecting DES in environmental water.

Bifunctional ligand-mediated amplification of polydiacetylene response to biorecognition of diethylstilbestrol for on-site smartphone detection

Polydiacetylene (PDA) is very suited for sensitively detecting large biomolecules, and its unique chromatic properties enable visual read-out. However, application to the selective detection of small molecules remains challenging. Here, bifunctional ligands are studied to amplify the color change of PDA for biorecognition of small molecules for the smartphone-based detection of diethylstilbestrol (DES). PDA is decorated with streptavidin (PDA-SA, blue), and biotin-modified DES (bio-DES) is prepared as a bifunctional ligand to couple with PDA-SA and DES antibody. Since multiple bio-DES can bind to a single SA, then multiple SAs on PDA lead to an increased surface coverage of the vesicle. In samples without DES, PDA-SA-bio-DES-DES antibody complexes will form, leading to a color transition (blue to red); this color transition is greatly amplified by antibody-induced aggregation of the complexes. When DES is present, aggregation is inhibited due to competition for the antibody and PDA-SA-bio-DES retains its blue color. A linear relationship (0.4–1250 ng mL−1) is found between the colorimetric response and the logarithmic DES concentration, with adequate selectivity, accuracy (82.24–118.64%), and precision (below 8.24%). Finally, a paper-based DES PDA biosensor is developed with visual and smartphone-based detection limits of 10 ng mL−1 and 0.85 ng mL−1 in water, respectively.

Electrochemical determination of diethylstilbestrol in livestock and poultry meats by L-cysteine/gold nanoparticles modified electrode

A fast and simple electrochemical method for the determination of diethylstilbestrol (DES) was developed. Gold nanoparticles stabilized by chitosan (AuCS) were prepared and used in combination with L-cysteine (L-Cys) by self-assembly for fabricating the electrochemical sensors. Compared with unmodified electrode, the oxidation peak current of DES could be increased greatly by using the L-Cys/AuCS modified GCE (L-Cys/AuCS/GCE), indicating L-Cys/AuCS had excellent ability to promote electron transfer. Under the optimal conditions, the oxidation peak current was linear to the concentration of DES in the range from 5 × 10−7 to 1 × 10−4 mol/L (r = 0.997) with the detection limit of 1.7 × 10−7 mol/L (S/N = 3). The proposed method was successfully used for the determination of DES in livestock and poultry meats with the satisfying recovery results (75.3–91.9%). The method not only exhibited good accuracy and reproducibility for DES detection, but also had the advantages of low cost, simple preparation method and convenient for batch preparation.

A Better Understanding of Diethylstilbestrol Electro‐oxidation: Towards the Design of an Electrochemical Sensor

AbstractThe obstacle for the development of a reliable electrochemical technique to trace diethylstilbestrol (DES) lies in the complex electrochemical behavior of this illicit hormone. The present study targeted to thoroughly investigate and understand the electro‐oxidation of DES in acetonitrile on gold electrode by cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. DES voltammogram has shown two anodic peaks, implicating two successive and irreversible processes. Adsorption and diffusion properties were studied and characterized using electrochemical, spectroscopic and morphological techniques. Avoiding adsorption, and under diffusion process only, a good linear correlation between peak current and DES concentration in the range of 0.25 to 1000 μmol/L was obtained with a detection and quantification limits of 0.2 μmol/L and 0.7 μmol/L, respectively, and a sensitivity of 0.016 A/mM. Competitivity tests, between DES and its structural analog hexestrol (HS), were carried out by chronoamperometry and SWV. HS even added in excess was found to merely affect DES electrochemical measurement. The established method exhibited high precision and reproducibility, and allows the easy and successful determination of DES in poultry feed sample. With a deep insight into its complex electrochemical behavior, this work paves the way to the development of selective, sensitive and easy‐to‐use electrochemical sensors directed towards this synthetic hormone and the related chemicals such as phenolic compounds.

One-pot synthesis of nitrogen doped graphene-thionine-gold nanoparticles composite for electrochemical sensing of diethylstilbestrol and H2O2

In this work, a facile, one-pot, and green synthetic approach was proposed to prepare a novel nanocomposite of nitrogen doped graphene-thionine-gold nanoparticles (NG-Thi-AuNPs), which was then modified on electrode to fabricate an electrochemical sensor for diethylstilbestrol (DES) accurate and reliable detection based on ratiometric strategy. The synthesized NG-Thi-AuNPswas characterized by transmission electron microscope, scanning electron microscope, Fourier transform infrared spectrum, and X-ray diffraction. Due to the merits of good conductivity and high electroactive surface of NG and AuNPs, as well as the synergistic interaction toward DES, the nanocomposite showed high sensitivity for DES detection. Moreover, the modified Thi exhibited a constant current response regardless how the DES concentration changed, which made Thi to be a good inner reference to improve the accuracy and reliability of the sensor. Thus, a ratiometric signal (ΔiDES/ΔiThi) was measured and calculated for DES detection with a wide linear range and a low limit of detection of 5.0 × 10−8 - 8.0 × 10−5 mol/L and 9.6 × 10−9 mol/L, respectively. Due to the excellent conductivity and high electrocatalytical activity of the nanocomposite, the sensor was employed for the sensitive detection of H2O2 with the linear range of 5.0 × 10−7- 1.0 × 10−2 mol/L. With the good anti-interference, reproducibility, and stability, the prepared sensor was successfully used for real samples determination.

Sandwich magnetically imprinted immunosensor for electrochemiluminescence ultrasensing diethylstilbestrol based on enhanced luminescence of Ru@SiO2 by CdTe@ZnS quantum dots

A molecularly imprinted magnetic sensor with electroluminescent tags (MIP-ECL sensor) was developed for ultrasensing diethylstilbestrol (DES). A strategy is exploited to enhance ECL emission of the [Ru(bpy)3]2 +-tripropyl amine (TPrA) system by CdTe@ZnS quantum-dots (QDs) through energy transfer. Magnetically molecularly imprinted nanoparticles (MMIPs NPs) based on Fe3O4@SiO2 carriers are artificial, easily reproducible, and could replace easily inactivated first antibodies for capturing more DES molecules. Functionalized bio-conjugates of single antibody-CdTe@ZnS (Ab-CdTe@ZnS) are for the first time loaded on signal labels of Ru(bpy)32 +-doped silica nanocomposites (Ru@SiO2) for signal amplification. The final bio-conjugated signal probes are denoted as Ab-DES/CdTe@ZnS–Ru@SiO2. MMIPs beads that have captured antigens are bio-conjugated with antibody-labeled luminescent probes by specific immunoreactive reaction, and then the luminescent immunocomplex generates ECL signal on the magnetic electrode. The logarithm of ECL intensities depend linearly on the logarithm of DES concentrations in the range from 4.8 × 10− 4 to 36.0 nM with a detection limit of 0.025 pM. This novel assay is much more sensitive than other MIP sensors, and achieves lower cost and more enhanced stability than other immunosensors. The sensor is significantly potential and has been applied to DES detection in actual environment.

Electrochemiluminescence solid-state imprinted sensor based on graphene/CdTe@ZnS quantum dots as luminescent probes for low-cost ultrasensing of diethylstilbestrol

A novel molecularly imprinted electrochemiluminescence (MIP-ECL) sensor was fabricated for diethylstilbestrol (DES), which exploited the strategy of specific identification by molecularly imprinted polymers (MIPs) instead of expensive biomolecules. Core-shell quantum-dots (QDs) of CdTe@ZnS were utilized to enhance ECL emission. The sensor was assembled as a solid-state electrode by immobilizing CdTe@ZnS/reduced-graphene oxide (r-GO) composite on a glassy carbon electrode (GCE) surface, and then being covered with MIPs film with specific cavities. The fabricated sensor (denoted as MIP/CdTe@ZnS/r-GO/GCE) was based on the obstruction of ECL signals by DES molecules enriched on MIP film. The ECL intensity of the QDs-K2S2O8 system was reduced when the DES molecules were selectively rebound onto the MIP film by molecularly imprinted solid phase extraction (MISPE). Accordingly, the logarithm of the quenched ECL intensity versus the logarithm of the DES concentration was in a good linear relationship over a wide range from 1.8 × 10− 3 to 25.0 nmol/L with the limit of detection (LOD) of 0.25 pmol/L (S/N = 3). The sensor also exhibits excellent selectivity with fast response and good accuracy. Lake water and milk samples were assayed by this sensor, and the recoveries ranging from 92.2%–108.3% were obtained.

Estrogens in municipal wastewater and receiving waters in the Beijing-Tianjin-Hebei region, China: Occurrence and risk assessment of mixtures

The potentially high release of estrogens to surface waters due to high population density and local livestock production in the Beijing-Tianjin-Hebei region may pose adverse effects on reproductive systems of aquatic organisms. This study found that total measured concentrations of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2) and diethylstilbestrol (DES) were 468 ± 27 ng/L in treated wastewater and 219 ± 23 ng/L in river waters in this region. E2, E3 and EE2 were the predominant estrogens in river waters. The restriction of DES for human use should have been enforced, however concentrations of DES were relatively high compared to other studies. Haihe and Yongdingxin Rivers delivered approximately 1.8 tonnes of estrogens to the Bohai Bay annually. Concentrations of individual estrogens were significantly higher in river waters in the dry season, however, mass loadings were significantly higher in the wet season. The average E2-equivalent concentrations reached 1.2 ± 0.2 and 0.64 ± 0.08 μg-E2/L following long-term and short-term exposure estimates, respectively, in river waters with an EE2 contribution of over 90 %. This could give rise to high risks to fish. Estrogens in river waters largely derived from human excretion. Field studies on estrogenic effects on fish reproductive systems are required locally considering high estrogen contamination levels.

Isolation and Characterization of a Novel Diethylstilbestrol-Degrading Bacillus subtilis JF and Biochemical Degradation Metabolite Analysis.

Diethylstilbestrol (DES) can adversely affect the immune system of developing fetuses or even elicit toxic responses such as nerve toxicity and genotoxicity in human beings, thereby warranting methods to remove DES from the environments. The present study characterized a novel DES-degrading Bacillus subtilis JF and analyzed the degradation metabolites. The strain was collected at the China General Microbiological Culture Collection Center (Collection number: CGMCC 7950). The environmental effects, such as DES concentrations, pH levels, and temperature, on the strain’s degradation ability were tested. Degradation metabolites of DES by strain JF were analyzed via high performance liquid chromatography (HPLC) and liquid-chromatography time of flight mass spectrometry (LC-TOF-MS). Results indicated that B. subtilis JF can effectively degrade DES within a concentration of 25–200 mg/L. Increasing pH levels (pH > 7) are reported to increase the degradation rate of DES by the strain. The optimal temperature for strain JF to degrade DES was identified as 45°C. In this study, 4, 4′-hexene estrogen quinones (DESQ) and DES-4-semiquinone were speculated as two degradation metabolites of DES, and both can be completely degraded by strain JF. A slight reduction of DES in the blank system [DES cultured in Luria-Bertani (LB) medium without strain JF] was observed in this study. The reduction trend in the blank system only occurred during the first few days (about 4 days) and was considerably lesser than the decomposition and transformation effect of DES via strain JF. Furthermore, the metabolite DESQ could not be further decomposed in blank LB medium without strain JF. All the results demonstrate that complete degradation of DES in the fermentation broth occurs due to the function of strain JF rather than organic decomposition. In conclusion, the high efficiency of degradation and the potential to degrade DES completely indicates that strain JF has potential for the bioremediation of DES-contaminated environments (soil, river, and so on) and fermented foods.

Diethylstilbestrol inhibits human and rat 11β-hydroxysteroid dehydrogenase 2.

Glucocorticoid hormone might cause intrauterine growth restriction. The glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase 2 (HSD11B2) in the placenta eliminates excess levels of glucocorticoids during pregnancy. The aim of the current study was to define the effects of diethylstilbestrol (DES) on HSD11B2 activity in the mammalian placentas and identify its mode of action. Rat and human placental microsomal HSD11B2 were incubated with different concentrations of DES, and IC50 values were determined. The mode of action was analyzed by incubation of DES together with substrates, glucocorticoid and NAD+. DES suppressed rat and human HSD11B2 with IC50 values of 5.33 and 12.62 μM, respectively. DES was a competitive inhibitor of rat and human HSD11B2 when steroid substrates were added, while it was an uncompetitive inhibitor when cofactor NAD+ was exposed. Oral administration of DES (0.5 mg/kg) to the rat delayed the cortisol metabolism in adult female Sprague–Dawley rats, as indicated by the increases in cortisol’s elimination half-life, maximum concentration and area under the curve. In conclusion, DES is a potent HSD11B2 inhibitor, possibly contributing to the intrauterine growth restriction.

Turn-on fluorometric immunosensor for diethylstilbestrol based on the use of air-stable polydopamine-functionalized black phosphorus and upconversion nanoparticles.

The preparation of air-stable black phosphorus (BP) is challenging because atomic layers of BP degrade rapidly on exposure to oxygen. A strategy is presented for the synthesis of BP functionalized with polydopamine (PDA/BP). Dopamine was self-polymerized to yield polydopamine (PDA) which then was used to coat the surface of BP. PDA can be easily reduced and this prevents BP degradation. PDA/BP also is a viable matrix for the adsorption of proteins due to the presence of functional groups. Without any chemical activation, diethylstilbestrol (DES)-specific monoclonal antibody was adsorbed on the PDA/BP surface. PDA/BP quenches the fluorescence antigen-modified NaYF4:Yb,Ho,Nd upconversion nanoparticles (UCNPs; photoexcited at 808 nm) via specific immuno recognition. Exposure to DES causes the dissociation of UCNP from the PDA/BP surface and fluorescence at 475, 525, 545 and 660nm to recover. This is due to the DES competition with antigen for binding to theantibody. Based on thiscompetitive immuno mechanism, a turn-on fluorometric immunoassay was constructed. It has a response that covers the 0.1 to 1000ngmL-1 DES concentration range with a detection limit of 83pgmL-1. This method was successfully applied to the determination of DES in spiked food and human urine samples. Graphical abstract Air-stable polydopamine-functionalized black phosphorus was obtained by modification of black phosphorus with polydopamine and then was coupled with specific monoclonal antibody. Combined with antigen-modified upconversion nanoparticles, a turn-on fluorometric immunoassay was constructed to detect diethylstilbestrol.

A competitive photoelectrochemical immunosensor for the detection of diethylstilbestrol based on an Au/UiO-66(NH2)/CdS matrix and a direct Z-scheme Melem/CdTe heterojunction as labels

A novel photoelectrochemical (PEC) bioassay protocol for diethylstilbestrol (DES) was systematically proposed. The Au/UiO-66(NH2) hybrid with countless active sites was fabricated using an in situ reduction strategy and was subsequently decorated with CdS nanoparticles (NPs) by a sequential chemical bath deposition process. The resulting Au/UiO-66(NH2)/CdS composites were exploited as a sensing matrix for the first time. The excellent photocurrent response of the as-prepared hybrid under visible light is attributed to its improved photo-electric conversion efficiency due to the local surface plasma resonance (LSPR) effect of Au and the matching energy-level structure between UiO-66(NH2) and CdS. In addition, the competitive strategy for the detection of DES was devised by employing the direct Z-scheme Melem/CdTe heterojunction covalently conjugated with bovine serum albumin (BSA)-DES as signal tags. As a consequence, a cascade-like band-edge level was obtained, which could effectively promote the transfer of photogenerated charges and markedly improve the photocurrent. On the basis of the above strategy, the concentrations of DES could be detected through the competitive binding of DES antibodies (Anti-DES) with either Melem/CdTe/BSA-DES or free DES. Under optimal conditions, the linear range for the detection of DES was 0.1 pg mL−1 to 20 ng mL−1. The detection limit was as low as 0.06 pg mL−1 (S/N = 3). Furthermore, the designed PEC DES-sensing approach has acceptable selectivity, reproducibility, and stability and offers great promise for the detection of small molecules in biomedical, food and environmental samples.

Electrochemical magnetic imprinted sensor based on MWCNTs@CS/CTABr surfactant composites for sensitive sensing of diethylstilbestrol

A selective and simple method for electrochemical determination of diethylstilbestrol (DES) was developed based on novel magnetic molecularly imprinted nanoparticles (MMIPs NPs) in this paper. Multilayer core-shell type superparamagnetic and water-compatible MMIPs (WMMIPs) NPs were prepared in aqueous media using 3‑aminophenylboronic acid (APBA) as the water-soluble functional monomer. Moreover, WMMIPs, surfactant hexadecyl trimethyl ammonium bromide (CTABr) and a composite of multi-walled carbon nanotubes coated with chitosan (MWCNTs@CS) were stepwise modified on the surface of a magnetic glassy carbon electrode (MGCE) in order to enhance the electron transfer rate, increase electrode surface area for more loaded capture probes of WMMIPs and effectively improve the detection sensitivity of the sensor. The prepared sensor was denoted as WMMIPs/MWCNTs@CS/CTABr/MGCE. Scanning electron microscopy (SEM), ultraviolet–visible (UV–vis) spectrophotometry, Fourier transform infrared spectroscopy (FT–IR) and vibration sample magnetometry (VSM) were used to characterize the nanocomposite. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical behaviors of the modified electrode. Square wave voltammetry (SWV) was employed for the determination of DES, and the oxidation peak currents showed a well linear relationship with the logarithmic values of DES concentrations in the wide range of 1.5 × 10−9 to 1.5 × 10−4 mol L−1 with correlation coefficient of 0.9986. The detection limit was 2.5 × 10−10 mol L−1 (S/N = 3). The developed sensor exhibited good reproducibility, stability and selectivity, and was successfully applied to DES determination in actual milk and lake water samples.

Ultrasensitive competitive method-based electrochemiluminescence immunosensor for diethylstilbestrol detection based on Ru(bpy)32+ as luminophor encapsulated in metal–organic frameworks UiO-67

In this work, Ru(bpy)32+ encapsulated in metal–organic frameworks (MOFs) UiO-67 (Ru(bpy)32+/UiO-67) as luminophor was easily prepared and firstly applied in constructing an electrochemiluminescence (ECL) immunosensor to efficiently estimate diethylstilbestrol (DES). The competitive method-based ECL immunosensor platform was fabricated by amino-silicon dioxide which possesses large surface area. The poriness of UiO-67 was splendid so that Ru(bpy)32+ could be easily encapsulated. Ru(bpy)32+/UiO-67 with excellent ECL luminescence signal existed large specific surface area for easily labeled with antibodies. DES competed with bovine serum albumin-diethylstilbestrol (BSA-DES) for binding to antibody-specific sites in the constructed immunosensor. However DES was micromolecule, which was easier to bond to antibodies than BSA-DES. The ECL signal was gradually decreases with the increase of the concentration of DES. Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.01 pg mL−1 to 50 ng mL−1 with a low detetion limit of 3.27 fg mL−1 (S/N = 3). The novel fabricated immunosensor with interference immunity and high stability may cause an attractive approach for the other targets determination.

Diethylstilbestrol impaired oogenesis of yellow catfish juveniles through disrupting hypothalamic-pituitary-gonadal axis and germ cell development.

Diethylstilbestrol (DES), a non-steroidal estrogen, has been found to cause altered germ cell development and disordered ovarian development in fish females. However, the mechanisms that might be involved are poorly understood. In this study, female juveniles of yellow catfish (Pelteobagrus fulvidraco) (120days post-hatching) were exposed to two doses (10 and 100ng l-1 ) of DES for 28days. After the endpoint of exposure, decreased ovary weight and gonadosomatic index, as well as various ovarian impairments were observed in response to DES. Besides, DES elevated the mRNA levels of vitellogenin 1 (vtg 1) and estrogen receptor 1 (esr 1) in liver and decreased 17β-estradiol level in plasma. Correspondingly, suppressed mRNA levels of the key genes in the hypothalamic-pituitary-gonadal axis (such as cyp19a1b, gnrh-II, fshβ and lhβ in brain and fshr, lhr and cyp19a1a in ovary) after DES exposure were also observed. The declined level of plasma 17β-estradiol and altered gene expressions of genes in the hypothalamic-pituitary-gonadal axis were thus supposed to be closely related to the disrupted oogenesis in DES-treated fish. Analyses further demonstrated that, higher concentration of DES elevated the expression ratio of bax/bcl-2, indicating the enhanced apoptosis occurred in ovary. Moreover, DES upregulated the expressions of genes involved in proliferation (cyclin d1 and pcna), meiotic entry (cyp26a1 and scp3) and meiotic maintenance (dmc1), resulting in arrested oogenesis in catfish. The present study greatly extended our understanding on the mechanisms underlying of reproductive toxicity of DES on fish oogenesis.

Synthesis of a nanocomposite consisting of Cu2O and N-doped reduced graphene oxide with enhanced electrocatalytic activity for amperometric determination of diethylstilbestrol

The authors report on a low temperature method for large-scale fabrication of cuprous oxide nanocubes deposited on nitrogen-doped reduced graphene oxide (Cu2O/N-RGO). The material was deposited in a glassy carbon electrode (GCE) where it is found to display enhanced electrocatalytic activity for oxidation of diethylstilbestrol (DES). The morphology and composition of Cu2O/N-RGO were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and energy-dispersive spectroscopy. The results demonstrate that the RGO is doped with 3.5% of nitrogen (atomic ratio), and that nanostructured Cu2O particles with controlled cubical morphology and an average size of about 450 nm have been homogeneously deposited on the surface of N-RGO sheets. The oxidation peak of DES was recorded at 0.315 V (vs. saturated calomel electrode) using differential pulse voltammetry. Under the optimal conditions, the modified GCE displays a linear response in the 0.3 to 150 μM DES concentration range, and the limit of detection is 10 nM. The method was applied to the determination of DES in spiked milk, meat and urine samples and gave excellent selectivity, stability and reproducibility.