Ultratrace analysis of atrazine in soil using Ice Concentration Linked with Extractive Stirrer and High Performance Liquid Chromatography-Tandem Mass Spectrometry

A highly sensitive and selective photoelectrochemical aptasensor for atrazine based on Au NPs/3DOM TiO2 photonic crystal electrode

A photoelectrochemical (PEC) sensing platform with high sensitivity and selectivity has been fabricated based on Au nanoparticles (Au NPs) modified three dimensionally ordered macroporous (3DOM) TiO₂ nanostructure frame for trace detection of an endocrine disrupting pesticide, atrazine (ATZ). The resultant photoanode (Au NPs/3DOM TiO₂) shows enhanced PEC performance under visible light due to multi signal amplification of the unique structure of 3DOM TiO₂ and surface plasmon resonance (SPR) of Au NPs. ATZ aptamers are used as recognition elements and immobilized on Au NPs/3DOM TiO₂ by Au-S bond in large packing density and dominant spatial orientation. The specific recognition and high binding affinity between aptamer and ATZ provides the PEC aptasensor with excellent sensitivity. The detection limit is 0.167 ng/L. Besides, this PEC aptasensor exhibits outstanding anti-interference ability in 100-fold concentration of other endocrine disrupting compounds and has been applied successfully to analyze ATZ in real water samples. A simple but efficient PEC aptasensing platform has therefore been successfully developed with high sensitivity, selectivity and repeatability for pollutant monitoring and potential risk evaluation in the environment with great application prospect.

Universal and rapid detection of atrazine and bisphenol A using a reusable optical fiber chemiluminescent biosensor

Timely and accurately detection of small molecule pollutants is quite necessary to control environmental pollution and reduce harmfulness. Herein, a reusable optical fiber chemiluminescent biosensor (ROFC) was proposed for universal and rapid detection of two representative pollutants, pesticide atrazine (ATZ) and endocrine disruptor bisphenol A (BPA). The optical fiber modified with hapten-protein conjugates was regarded as both bio-probe and chemiluminescence signal transmission element, which effectively improved the light transmission efficiency and signal-to-noise ratio of the system. High-sensitive chemiluminescence signal detection is realized with a miniaturized ultrasensitive photodiode detector. Good regeneration performance of bio-probe can reduce detection cost and ensure detection reproducibility. Based on indirect competitive immunoassay principle, the chemiluminescence signal decreased with increasing pollutant concentration resulting from the less amount of antibody combined on the bio-probe surface. Under optimal conditions, the whole assay was achieved within 25 min with linear range of 1-100 μg/L and detection limits (LOD) for atrazine and BPA are 0.029 μg/L and 0.025 μg/L, respectively. The immunosensing optical fiber probe can be reused for 150 times at least without losing obvious bioactivity. The method was successfully applied to the detection of ATZ and BPA in three environmental samples, where recoveries between 93.4% and 116.6% were achieved. The ROFC biosensor provides a feasible platform for rapid detection of multiple small molecule pollutants in the environment.

Tannic acid through ROS/TNF-α/TNFR 1 antagonizes atrazine induced apoptosis, programmed necrosis and immune dysfunction of grass carp hepatocytes

Atrazine (ATR) is a commonly used triazine herbicide, which will remain in the water source, soil and biological muscle tissue for a long time, threatening the survival of related organisms and future generations. Tannic acid (TAN), a glucosyl compound found in gallnuts, has previously been shown to antagonize heavy metal toxicity, antioxidant activity, and inflammation. However, it is unclear whether TAN can antagonize ATR-induced Grass carp hepatocytes (L8824 cells) cytotoxicity. Therefore, we treated L8824 cells with 3 μg mL^-1 ATR for 24 h to establish a toxic group model. The experimental data of flow cytometry and AO/EB staining together showed that the ratio of apoptosis and necrosis in L8824 cells after ATR exposure was significantly higher than that in the control group. Furthermore, RT-qPCR showed that inflammatory factors (TNF-α, IL-1β, IL-6, INF-γ) were up-regulated and antimicrobial peptides (hepcidin, β-defensin and LEAP2) were induced down-regulated in L8824 cells, leading to immune dysfunction. The measurement results of oxidative stress-related indicators showed that the levels of ROS and MDA increased after ATR exposure, the overall anti-oxidative system was down-regulated. Western blotting confirmed that TNF-α/TNFR 1-related genes were also up-regulated. This indicates that ATR stimulates oxidative stress in L8824 cells, which in turn promotes the binding of TNF-α to TNFR 1. In addition, TRADD, FADD, Caspase-3, P53, RIP1, RIP3 and MLKL were found to be significantly up-regulated by Western blotting and RT-qPCR. Conditioned after ATR exposure compared to controls. It indicates that ATR activates apoptosis and necrosis of TNF-α/TNFR 1 pathway by inducing oxidative stress in L8824 cells. Furthermore, the use of TAN (5 μM) significantly alleviated the toxic effects of ATR on L8824 cells mentioned above. In conclusion, TAN restrains ATR-induced apoptosis, programmed necrosis and immune dysfunction through the ROS/TNF-α/TNFR 1 pathway.