title: A high-performance glucose biosensor based on monomolecular layer of glucose oxidase covalently immobilised on indium-tin oxide surface.
abstract: In this paper, a mediatorless amperometric glucose biosensor based on direct covalent immobilisation of monomolecular layer of glucose oxidase (GOx) on a semiconducting indium-tin oxide (ITO) is demonstrated. The abundance of surface hydroxyl functional group of ITO allows it to be used as a suitable platform for direct covalent immobilisation of the enzyme for sensor architecture. The anodic current corresponding to electrochemical oxidation of the enzymatic product, hydrogen peroxide, at a sputtered Pt electrode at 0.500 V (vs. SCE) was obtained as the sensor signal. It was found that the biosensor based on the direct immobilisation scheme shows a fast biosensor response, minimum interference from other common metabolic species and ease of biosensor miniaturisation. A linear range of 0-10 mM of glucose was demonstrated, which exhibits a high sensitivity as far as performance per immobilised GOx molecule is concerned. A detection limit as low as 0.05 mM and long-term stability were observed. Even more important, the biosensor design allows fabrication through a dry process. These characteristics make it possible to achieve mass production of biosensor compatible with the current electronic integrated circuit manufacturing technologies.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Aiping
authors.initials: A
authors.lastname: Fang
authors.forename: Hou Tee
authors.initials: HT
authors.lastname: Ng
authors.forename: Sam Fong Yau
authors.initials: SF
authors.lastname: Li
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001786:Blood Glucose / Q000032:analysis; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005947:Glucose / Q000032:analysis* / Q000737:chemistry*; D005949:Glucose Oxidase / Q000737:chemistry*; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D001786:Blood Glucose; D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D017971:Tin Compounds; C109984:indium tin oxide; D005949:Glucose Oxidase; D005947:Glucose