Development of an enzyme-functionalized immunosensor for measuring maturation-inducing hormone in fish

Abstract

In modern aquaculture, simple and rapid methods of predicting fish ovulation are needed to produce seedlings in a stable and efficient manner. Ovulation time is variable due to environmental and physiological factors, while 17α,20β-dihydroxy-4-pregnen-3-one (DHP), an indicator of ovulation, increases its concentration rapidly just before spawning. In this paper, we developed a biosensor system in which immune and enzymatic reaction assays were combined to monitor DHP levels with low environmental loads. We attempted to quantify DHP by analyzing the decrease rate in the output current after the immunoreaction using the amperometric method as a transfer inhibition degree of the enzyme-generated electrons generated by the formation of the antigen-antibody complex. DHP standard samples were measured under investigated optimal conditions and a specific response with a good linear correlation was obtained between the current decrease rate of the sensor system and the DHP concentration in a range of 7.81∼500 pg ml−1. Further, DHP levels in goldfish (Carassius auratus) during the ovulation period obtained using the sensor system were compared with those of using the conventional method (ELISA) and a good correlation was obtained. These findings suggest that the proposed sensor system can detect DHP quickly and easily compared with the conventional method.