Electrochemical biosensor for β-hydroxybutyrate based on NADH oxidase-like mimics of Pt NPs@MWCNTs

By in situ reduction of Pt nanoparticles (Pt NPs) onto the surface of multi-walled carbon nanotubes (MWCNTs), Pt NPs@MWCNTs nanocomposite was successfully synthesized. Experimental results indicate the nanocomposite exhibits good NADH oxidase activity, which can generate •O 2− through O 2 and efficiently catalyze the oxidation of nicotinamide adenine dinucleotide (NADH) to generate biologically active NAD + . Based on this characteristic, we developed an NAD + /NADH dependent dehydrogenase electrochemical cascade biosensor for the detection of β-hydroxybutyric acid (HB) via β-hydroxybutyrate dehydrogenase that does not require additional redox mediators. This biosensor exhibited good performance for HB with high sensitivity and good specificity, and a wide linear range of 10 µM to 10 mM. To verify its practical application, the biosensor was applied to the detection of HB in human serum samples, which indicate the biosensor has potential for clinical diagnosis of diabetes ketoacidosis.