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Bioactive Hydrogel Layers on Microdisk Electrode Arrays: Impedimetric Characterization and Equivalent Circuit Modeling
Author(s) -
Rahman Abdur Rub Abdur,
Justin Gusphyl,
GuiseppiElie Anthony
Publication year - 2009
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200804540
Subject(s) - dielectric spectroscopy , resistive touchscreen , electrode , equivalent circuit , capacitance , materials science , ferrocene , electrical impedance , electrochemistry , analytical chemistry (journal) , cyclic voltammetry , thermal diffusivity , layer (electronics) , diffusion , chemistry , chemical engineering , nanotechnology , chromatography , voltage , physics , quantum mechanics , electrical engineering , engineering , thermodynamics
Microfabricated microdisk electrode arrays (MDEAs) of 50 μm (5184 disks), 100 μm (1296 disks) and 250 μm (207 disks) ( d / r =4; A= 0.1 cm 2 ) were coated with poly(hydroxyethylmethacrylate)‐based hydrogel membranes and studied by electrochemical impedance spectroscopy (EIS) in 1.0 mM ferrocene monocarboxylic acid (FcCO 2 H). Equivalent circuit modeling showed an approximate three‐fold increase in solution resistance, R sol , and an order of magnitude increase in charge transfer resistance, R ct, resulting from a reduction in apparent diffusivity of FcCO 2 H. Additionally, both resistive parameters decreased while the capacitance ( Q ) increased with decreasing microdisk diameter; consistent with an increase in effective electroactive area. The hydrogel layer did not compromise enhanced mass transport achieved by the MDEA and thus may be used to advantage in biosensors.