ABSTRACT
Precise detection of 3-hydroxybutyrate (HB) in biological samples is of great importance for management of diabetic patients. In this study, an HB biosensor based on single-walled carbon nanotubes (SWCNTs)-modified screen-printed electrode (SPE) was developed to determine the concentration of HB in serum. The specific detecting enzyme, HB dehydrogenase, was physically immobilised on SWCNTs deposited on the surface of SPEs. The electrochemical measurement of HB that involved cyclic voltammetry was based on the sAgnal produced by j3-nicotinamide adenine dinucleotide (NADH), one of the products of the enzymatic reaction. The application of SWCNT reduced the oxidation potential of NADH to about -0.05 V. Electrochemical measurements showed that the response of this biosensor had relevant good linearity in the range of 0.1-2 mM with a low detection limit of 0.009 mM. Investigation of biosensor response in the presence of interfering molecules verified its specificity. Furthermore, the study of long-term stability demonstrated the acceptable efficiency of this biosensor for about 100 days.
Subject(s)
3-Hydroxybutyric Acid/analysis , Biosensing Techniques/instrumentation , Enzymes, Immobilized/chemistry , Hydroxybutyrate Dehydrogenase/chemistry , Nanotubes, Carbon/chemistry , 3-Hydroxybutyric Acid/blood , 3-Hydroxybutyric Acid/metabolism , Biosensing Techniques/methods , Electrochemical Techniques/instrumentation , Electrodes , Enzyme Stability , Enzymes, Immobilized/metabolism , Humans , Hydroxybutyrate Dehydrogenase/metabolism , Limit of Detection , NAD/analysis , NAD/chemistry , NAD/metabolismABSTRACT
Molecular imprinting is a useful technique for the preparation of functional materials with molecular recognition properties. In this work, a biomimetic potentiometric sensor, based on a non-covalent imprinted polymer, was fabricated for the recognition and determination of hydroxyzine in tablets and biological fluids. The molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization, using hydroxyzine dihydrochloride as a template molecule, methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylat (EGDMA) as a cross-linking agent. The sensor showed a high selectivity and a sensitive response to the template in aqueous system. The MIP-modified electrode exhibited a Nernstian response (29.4+/-1.0 mV decade(-1)) in a wide concentration range of 1.0x10(-6) to 1.0x10(-1) M with a lower detection limit of 7.0x10(-7) M. The electrode demonstrated a response time of approximately 15s, a high performance and a satisfactory long-term stability (more than 5 months). The method has the requisite accuracy, sensitivity and precision to assay hydroxyzine in tablets and biological fluids.
