Herein, we investigated the analytical features of potentiometric immunosensors for detection of alpha-fetoprotein (AFP) in hepatocellular carcinoma at different electrodes, such as carbon fiber microelectrode (CFME) and carbon-disk electrode (CDE), respectively. To construct such an immunosensor, anti-AFP capture antibodies were first conjugated covalently onto the activated electrodes through typical carbodiimide coupling. Thereafter, one-step immunoreaction protocol was successfully introduced to develop a new potentiometric immunoassay upon addition of AFP. Accompanying the antigen-antibody reaction, the surface charges of the modified electrodes were changed for the readout of electric potential. Results indicated that the linear range of CDE-based immunosensor was 0.1–100 ng mL−1 AFP, whereas the assay sensitivity by using CFME could be further increased to 3.2 pg mL−1 with the linear range from 0.01 to 500 ng mL−1 AFP. Meanwhile, CFME-based immunosensor showed high sensitivity, good reproducibility and specificity, and could be utilized for the analysis of human serum specimens with consistent results relative to commercialized ELISA kit. 相似文献
The flexible stretchable sensors have great potential for implementation in various applications, such as intelligent soft robots, health monitoring, and motion detection. However, most of the flexible stretchable sensors with microstructures and high sensitivities are fabricated by expensive templates and complex processes. In consideration of large-scale fabrication, a low cost and efficient way is in great demand. Herein, electroless plating on Nafion films with decent swelling ratios are proposed to fabricate stretchable sensors with wrinkle-structured electrodes. By adding isopropanol (IPA) to the electroless plating process, the H2O-IPA sensor with larger swelling ratio shows deeper surface wrinkles, higher surface roughness, and better sensitivity to strain. At the same time, the H2O-IPA sensor exhibit good durability (500 cycles). By mounting the sensor on the joint of human finger, the motion of the finger bending and even the bending degree can be accurately detected, indicating the potential use in the field of wearable devices and soft electronic skins. 相似文献
Ephedrae Herba is one of the most commonly used herbal medicines, and it has been shown that most of the clinical efficacy for cold and asthma is exerted by its alkaloidal components. A simple and sensitive high-performance liquid chromatography method was developed using a perfluorooctyl column for the simultaneous determination of five alkaloids (norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, and methylephedrine) in Ephedrae Herba. The mobile phase comprising acetonitrile and 15 mM ammonium trifluoroacetate was used to elute the targets in isocratic elution mode. The method was validated for linearity (R2 > 0.999), repeatability, intraday and interday precision, recoveries with trueness (93.87–110.99%), limits of detection (5.35–5.76 µg/mL), and limits of quantification (20 µg/mL). The quantitative results revealed that the developed method was precise and accurate. Then it was successfully applied to determine the difference in the contents of three batches of Ephedrae Herba from three pharmaceutical companies. 相似文献
Zinc molybdate (ZnMoO4), a layer perovskite material, has the advantages of high stability, excellent optical and charge properties. However, its high band gap and high electron–hole recombination efficiency limit its application in the photocatalytic reduction field like hydrogen production. In this study, we used CdS as a co-catalyst and successfully prepared CdS/ZnMoO4 composite photocatalysts with different loadings. The hydrogen evolution rate of CdS/ZnMoO4 reached 530.2 µmol h?1 g?1, which was approximately 11 and 100 times more than rates of pure CdS and ZnMoO4 under the same conditions, respectively. It is the presence of CdS that contributed to this improved performance, which acted as an electron acceptor to separate electrons and holes. Besides, a reasonable mechanism was provided based on photoelectrochemical characterizations. CdS loading greatly improved the hydrogen evolution performance of ZnMoO4 under visible light, providing a direction to improving the performance of perovskite based photocatalysts.