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

摘要

An extremely sensitive enzyme sensor for detection of 17 beta-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 17 beta-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 x 10(-13) - 5.7 x 10(-11) M and a limit of detection as low as 1.3 x 10(-13) M. Moreover, the enzyme sensor exhibited good reproducibility, stability and high selectivity to 17 beta-estradiol. Excellent performance was showed in the human urine samples analysis, thus confirming great prospect for further application in clinic diagnosis and biological research.