Coimmobilization of Dehydrogenases and Their Cofactors in Electrochemical Biosensors

• Published in: Analytical chemistry (Washington) Vol. 79; no. 6; pp. 2446 - 2450
• Main Authors: Zhang, Maogen, Mullens, Conor, Gorski, Waldemar
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-03-2007
• Subjects: Analytical chemistry; Biological and medical sciences; Biosensing Techniques - methods; Biosensors; Biotechnology; Chemical compounds; Chemistry; Chitosan - metabolism; Chromatographic methods and physical methods associated with chromatography; Electrochemical methods; Electrochemistry; Electrodes; Enzymes; Enzymes, Immobilized - metabolism; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gas chromatographic methods; Glucose - analysis; Glucose - metabolism; Mass Spectrometry; Methods. Procedures. Technologies; Molecular Structure; NAD - metabolism; Nanotubes; Oxidoreductases - metabolism; Sensitivity and Specificity; Thin films; Various methods and equipments; Water; Water; Electrochemical analysis; Oxygen; Molecular structure; Enzyme; Electrochemical method; Coimmobilization; Adenine; Dialdehyde; Carbon electrode; Carbon nanotubes; Selectivity; Glucose; Dehydrogenase; Cofactor; Gas chromatography; Enzymatic method; Sensitivity; Biosensor; Nicotinamide; Oxidoreductases; Chitosan; Aqueous solution; Molecular imprinting
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac061698n

Enzyme-based reagentless biosensors were developed using the model system of glucose dehydrogenase (GDH) and its nicotinamide adenine dinucleotide cofactor (NAD+). The biosensors were prepared following an approach similar to the concept of molecular imprinting. To this end, the N1-carboxymethyl−NAD+ species were covalently attached to polyamino−saccharide chains of chitosan (CHIT) and allowed to interact with GDH in an aqueous solution. The bioaffinity interactions between the NAD+ and GDH were secured by cross-linking the system with the glutaric dialdehyde (GDI)-modified CHIT. Electron conductive films of such CHIT−NAD+−GDH−GDI−CHIT macrocomplexes (MC) were prepared on glassy carbon (GC) electrodes by adding carbon nanotubes (CNT) and evaporating water. Electrochemical analysis of the GC/CNT−MC electrodes revealed that, in contrast to the oxidase-based electrodes, they acted as oxygen-independent reagentless biosensors. The application of Nafion to such biosensors predictably improved their selectivity and, unexpectedly, enhanced their sensitivity by an order of magnitude.