Construction of Electrochemical Biosensor Using Thionin-modified Electrode for Detecting Progesterone in Cattle Estrus

In the present study, a progesterone (P4) biosensor was developed to detect cattle estrus. Thionin, which has been reported to oxidize steroid hormones, was immobilized on an electrode via 10-carboxy-1-decanethiol with the aim of continuous measurement of P4 in the cattle body. On the screen -printed electrode, Au nanoparticles were electrodeposited on the surface of the carbon electrode to increase surface area of electrode. Finally, the thionin-modified electrode surface was covered with NafionTM. As a result, the influence of contaminants (BSA, L -ascorbic acid) was avoided. The detection range of the prepared sensor for P4 was 1 nM (= n mol/l)-20 nM. When bovine plasma was used as a biological sample, it was confirmed that the current response in i-t measurement increased due to the addition of P4. The fabricated biosensor was able to detect P4 for 4 days. It is expected that the P4 biosensor used in the present study will enable accurate understanding of cattle estrus.