▎ 摘　　要

Regular monitoring of circulating serum p-hydroxybutyrate is vital for dairy cattle health management. Herein, an electrochemical biosensor platform for rapid detection of p-hydroxybutyrate is described that is simple to operate. The biosensor platform is constructed by integrating the covalently functionalized ruthenium (II)-graphene oxide/NAD' composite with subsequent modification of enzyme, 3-hydroxybutyrate dehydrogenase. As-functionalized biosensor platform display enhanced redox behavior at the interface with a current sensitivity of 22 +/- 2.51 mu A mM(-1). Immobilization of enzyme 3-hydroxybutyrate dehydrogenase makes the sensor platform selective to p-hydroxybutyrate, which induces the concentration dependent amperometric response suitable for field -deployable application. Further, practical applicability of the proposed biosensor platform is tested with serum samples of various p-hydroxybutyrate concentrations. In addition to better selectivity, the demonstrated enzyme integrated hybrid nanocomposite biosensor exhibit rapid response time (less than 1 min), providing a promising approach for on -farm diagnostics. (C) 2016 Elsevier B.V. All rights reserved.