A novel electrochemical enzyme biosensor for detection of 17ß-estradiol by mediated electron-transfer system.

An extremely sensitive enzyme sensor for detection of 17ß-estradiol based on electropolymerized L-lysine molecules on a glassy carbon electrode (GCE) modified with critic acid@graphene (CA-GR) and cross-linked with laccase enzyme has been developed in this work. As the laccase immobilization, glutaraldehyde was chosen as cross-linker through the groups reactions. The novel enzyme sensor could recognize and determinate 17ß-estradiol effectively. The morphology of the enzyme modified electrode was characterized by transmission electron microscopy (TEM) and electron microscopy (SEM). The amino interaction between cross-linker and enzyme was characterized by Fourier transform infrared spectroscopy (FTIR). Under the optimal experimental conditions, good linear relationships were achieved in the range of 4 × 10-13 - 5.7 × 10-11 M and a limit of detection as low as 1.3 × 10-13 M. Moreover, the enzyme sensor exhibited good reproducibility, stability and high selectivity to 17ß-estradiol. Excellent performance was showed in the human urine samples analysis, thus confirming great prospect for further application in clinic diagnosis and biological research.

Ordered Mesoporous NiCo2O4 Nanospheres as a Novel Electrocatalyst Platform for 1-Naphthol and 2-Naphthol Individual Sensing Application.

The novel ordered mesoporous NiCo2O4 (meso-NiCo2O4) nanospheres were synthesized by the nanocasting strategy followed by a calcination process for 2-naphthol (2-NAP) and 1-naphthol (1-NAP) individual sensing application. The as-obtained meso-NiCo2O4 material possesses mesoporous structure in spinel crystalline type with a larger specific surface area than other structures. The meso-NiCo2O4-modified carbon paste electrode exhibited excellent electrocatalytic performance for NAP detection by amperometry measurement. The fabricated sensor of 2-NAP and 1-NAP has a wide linear detection range (0.02-300 and 0.02-20 µM) with high sensitivity (1.822 and 1.510 µA µM-1 cm-2) and low limit of detection (0.007 and 0.007 µM), respectively. In addition, the NAP sensors possess excellent reproducibility, stability, and selectivity.