Interdigitated array microelectrodes for the determination of enzyme activities

An array of closely spaced interdigitated microelectrodes was applied to the sensitive detection of reversible redox couples. The measurement is based on the redox cyclization between the adjacent microband electrodes of the interdigitated array (IDA), when both the respective oxidation and reduction potential are applied at the electrode pairs. The multiple oxidation and reduction result in an increased generation of current. The steady-state current of mediators, such as phenazine methosulfate, hexacyanoferrate(II), pyrocatechol, benzoquinone and p-aminophenol, was amplified by a factor of 10–20 compared with the current of single electrodes. The high collection efficiency enabled this signal amplification rate to be obtained. The detection limit for p-aminophenol was 100 nmol l–1. The IDA sensor was applied to the determination of alkaline phosphatase and β-galactosidase activity by detecting enzymatically generated p-aminophenol.

[1]  L. Faulkner,et al.  Relationships between measured potential and concentrations of redox centers in polymer networks , 1992 .

[2]  J. Frew,et al.  Measurement of alkaline phosphatase activity by electrochemical detection of phosphate esters: application to amperometric enzyme immunoassay , 1989 .

[3]  Hisao Tabei,et al.  Electrochemical behavior of reversible redox species at interdigitated array electrodes with different geometries: consideration of redox cycling and collection efficiency , 1990 .

[4]  R. Murray,et al.  An electrochemical time-of-flight experiment , 1987 .

[5]  R. Murray,et al.  Interdigitated Array Electrode Diffusion Measurements in Donor/Acceptor Solutions in Polyether Electrolyte Solvents , 1991 .

[6]  Koichi Aoki,et al.  Quantitative analysis of reversible diffusion-controlled currents of redox soluble species at interdigitated array electrodes under steady-state conditions , 1988 .

[7]  M. Batchelor,et al.  Amperometric determination of total amylase , 1988 .

[8]  R. Murray,et al.  Micrometer-spaced platinum interdigitated array electrode: fabrication, theory, and initial use , 1985 .

[9]  J. Kulys,et al.  Kinetic amperometric determination of hydrolase activity , 1980 .

[10]  J. Rishpon,et al.  Alkaline phosphatase as a label for a heterogeneous immunoelectrochemical sensor: An electrochemical study , 1989 .

[11]  L. Faulkner,et al.  Use of microelectrode arrays to determine concentration profiles of redox centers in polymer films , 1992 .

[12]  Allen J. Bard,et al.  Digital Simulation of the Measured Electrochemical Response of Reversible Redox Couples at Microelectrode Arrays: Consequences Arising from Closely Spaced Ultramicroelectrodes , 1986 .

[13]  R. Murray,et al.  Measurement of electron diffusion coefficients through Prussian Blue electroactive films electrodeposited on interdigitated array platinum electrodes , 1986 .

[14]  U. Lövgren,et al.  Determination of drugs in biosamples at picomolar concentrations using competitive ELISA with electrochemical detection: application to steroids. , 1993, Journal of pharmaceutical and biomedical analysis.

[15]  S. Licht,et al.  Time and Spatial Dependence of the Concentration of Less Than 105 Microelectrode-Generated Molecules , 1989, Science.

[16]  William R. Heineman,et al.  p-aminophenyl phosphate: an improved substrate for electrochemical enzyme immnoassay , 1988 .

[17]  C. Meares,et al.  Synthesis of mono- and dinucleotide photoaffinity probes of ribonucleic acid polymerase. , 1981, Biochemistry.