Design considerations in the development and application of microdisc electrode arrays (MDEAs) for implantable biosensors

Abdur Rub Abdur Rahman, Anthony Guiseppi-Elie

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The use of microlithographically fabricated Microdisc Electrode Arrays (MDEAs) in the development of implantable voltammetric biosensors necessitates design criteria that balances the overall footprint of the device with the advantages to be derived from large separation distances between non-interacting microdisc elements. Using the dynamic electroanalytical techniques of Multiple Scan Rate Cyclic Voltammetry (MSRCV) experiments with finite element simulations and Electrochemical Impedance Spectroscopy with equivalent circuit modeling, three unique MDEA designs; MDEA 050 (r = 25 μm, 5,184 discs), MDEA 100 (r = 50 μm, 1,296 discs) and MDEA 250 (r = 125 μm, 207 discs) of constant critical dimensions (center-to-center d/r = 4) and area (A = 0.1 cm2) were studied in 1.0 mM ferrocene monocarboxylic acid (FcCO2H) solution (in 0.1 M Tris/0.1 M KCl buffer, pH = 7.2). The critical disc-to-disc spacing (d/r) required to archive 67% of maximal current response was defined as optimal. Based on the predictive model, new MDEA designs; MDEA 001 (r = 0.5 μm, 127,324 discs), MDEA 002.5 (r = 1.25 μm, 20,372 discs), MDEA 005 (r = 2.5 μm, 5,093 discs), MDEA 010 (r = 5 μm, 1,273 discs), MDEA 015 (r = 7.5 μm, 566 discs), MDEA 020 (r = 10 μm, 318 discs) were simulated at 10 and 100 mV/s. The final disc count of each MDEA was dictated by the need to maintain a comparable electroactive area between the MDEAs, which was chosen to be 0.001 cm2, which in turn was dictated by the need to generate sufficient electrochemical current to be comfortably measured by common electrochemical detectors.

Original languageEnglish (US)
Pages (from-to)701-710
Number of pages10
JournalBiomedical Microdevices
Volume11
Issue number3
DOIs
StatePublished - May 11 2009

Keywords

  • Biosensors
  • Impedance
  • Microelectrode arrays
  • Simulation
  • Ultramicroelectrodes
  • Voltammetry

ASJC Scopus subject areas

  • Biomedical Engineering
  • Molecular Biology

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