An electrochemical immunosensor for the detection of carcinoembryonic antigen based on Au/g-C3N4 NSs-modified electrode and CuCo/CNC as signal tag.

Carcinoembryonic antigen levels in the human body reflect the conditions associated with a variety of tumors and can be used for the identification, development, monitoring, and prognosis of lung cancer, colorectal cancer, and breast cancer. In this study, an amperometric immunosensor with CuCo/carbon nanocubes (CuCo/CNC) as the signal label is constructed. The bimetal-doped carbon skeleton structure has a high specific surface area and exhibits good electrocatalytic activity. In addition, Au/g-C3N4 nanosheets (Au/g-C3N4 NSs) are used to modify the substrate platform, facilitating the loading of more capture antibodies. The reaction mechanism was explored through electrochemical methods, X-ray powder diffraction, X-ray photoelectron spectroscopy, and other methods. Kinetic studies have shown that CuCo/CNC have good peroxidase-like activity. In addition, the electrocatalytic reduction ability of CuCo/CNC on hydrogen peroxide can be monitored using amperometric i-t curve (- 0.2 V, vs. SCE), and the response current value is positively correlated with the CEA antigen concentration. The prepared electrochemical immunosensor has good selectivity, precision, and stability. The dynamic range of the sensor was 0.0001-80 ng/mL, and the detection limit was 0.031 pg/mL. In addition, the recovery and relative standard deviation in real serum samples were 97.7-103 % and 3.25-4.13 %, respectively. The results show that the sensor has good analytical capabilities and can provide a new method for the clinical monitoring of CEA.

CeO2- and CaO-Promoted Precipitation Method for One-Step Preparation of Vermiculite-Based Multilayer Mesoporous Ni-Based Catalysts for Dry Reforming of Methane.

In this paper, a molecular sieve (VSiO2) prepared from modified vermiculite is used as a support, and a multilayer mesoporous catalyst, Ni-VSiO2, is prepared while the active components are loaded in one step by the precipitation method. The catalyst is further modified by adding additives Ca and Ce to prepare the catalyst Ni-5x-VSiO2 (x = Ce, Ca) and is used for the dry reforming of methane reaction. The catalyst is characterized by X-ray fluorescence, Brunauer-Emmett-Teller analysis, scanning electron microscopy, hydrogen temperature-programmed reduction test, transmission electron microscopy, thermogravimetric analysis, and other technical means. The result shows that under a normal pressure of 750 °C, the catalyst Ni-Ca-VSiO2 has good stability. The catalyst Ni-Ce-VSiO2 has good activity, stability and carbon deposition resistance, and the conversion rates of CO2 and CH4 are 88% and 78%, respectively. This is because the mesoporous structure allows Ni nanoparticles to enter the pores of the catalyst support, thereby inhibiting the aggregation of the active component Ni and improving its sintering resistance. CeO2 additives provide more oxygen vacancies to inhibit the formation of carbon deposits. At the same time, the strong interaction between the active component Ni and the additive CeO2 is also beneficial to improve its sintering resistance.

Study on the performance of a MOF-808-based photocatalyst prepared by a microwave-assisted method for the degradation of antibiotics.

In this paper, a simple method was used to rapidly prepare MOF-808 with a large specific surface area and high stability. Bi2S3 and MOF-808 were used to design and synthesize high-stability Bi2S3/MOF-808 nanocomposites, which were then used for the photocatalytic degradation of antibiotic tetracyclines. The performance test results showed that the 0.7-808 composite material had good photocatalytic degradation performance for tetracycline under visible-light irradiation, and the degradation rate reached 80.8%, which was 3.21 times and 1.76 times that of MOF-808 and Bi2S3, respectively. This was mainly due to the high photocurrent response and photoluminescence of the Bi2S3/MOF-808 composite material. Therefore, the close contact of n-n Bi2S3/MOF-808 can transfer light-generated electrons and holes to improve the utilization efficiency of photogenerated charges, thereby greatly improving the photocatalytic reaction activity. Particle-capture experiments and ESR confirmed that ˙OH was the main active substance in the photocatalytic degradation.