title: Electrocatalytic detection of insulin at RuOx/carbon nanotube-modified carbon electrodes.
abstract: A bilayer surface coating, prepared by electrodepositing ruthenium oxide (RuOx) onto a carbon nanotube (CNT) layer, offers dramatic improvements in the stability and sensitivity of voltammetric and amperometric measurements of insulin compared to the individual (CNT or RuOx) coated electrodes. The enhanced electrocatalytic activity towards insulin is indicated from lowering the potential of the oxidation process (starting around 0.35 versus Ag/AgCl) and the substantially higher sensitivity over the entire potential range. A wide linear dynamic range (10-800 nM) was achieved with a detection limit of 1 nM. The marked electrocatalytic activity of the RuOx/CNT coating towards insulin is coupled with a greatly enhanced stability. For example, the insulin amperometric response of the RuOx/CNT-coated electrodes is highly stable, with 97% of the initial activity remaining after 60 min stirring of 2 x 10(-6) M solution (compared to significantly faster current diminutions at the RuOx- or CNT-coated surfaces). The results suggest great promise for miniaturized sensors and detectors for monitoring insulin.
authors: Departments of Chemical and Material Engineering, Chemistry and Biochemistry, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5801, USA. joseph.wang@asu.edu <joseph.wang@asu.edu>
authors: Joseph
authors: J
authors: Wang
authors: Tanin
authors: T
authors: Tangkuaram
authors: Suchera
authors: S
authors: Loyprasert
authors: Terannie
authors: T
authors: Vazquez-Alvarez
authors: Waret
authors: W
authors: Veerasai
authors: Proespichaya
authors: P
authors: Kanatharana
authors: Panote
authors: P
authors: Thavarungkul
mesh_terms: D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D007328:Insulin / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000032:analysis*; D010084:Oxidation-Reduction; D010087:Oxides / Q000032:analysis* / Q000737:chemistry; D017975:Ruthenium Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D007328:Insulin; D037742:Nanotubes, Carbon; D010087:Oxides; D017975:Ruthenium Compounds