Analytical and Bioanalytical Chemistry

, Volume 397, Issue 4, pp 1493–1502

3D nanogap interdigitated electrode array biosensors

  • Kanwar Vikas Singh
  • Allison M. Whited
  • Yaswanth Ragineni
  • Thomas W. Barrett
  • Jeff King
  • Raj Solanki
Original Paper

DOI: 10.1007/s00216-010-3682-z

Cite this article as:
Singh, K.V., Whited, A.M., Ragineni, Y. et al. Anal Bioanal Chem (2010) 397: 1493. doi:10.1007/s00216-010-3682-z

Abstract

Three-dimensional interdigitated electrodes (IDEs) have been investigated as sensing elements for biosensors. Electric field and current density were simulated in the vicinity of these electrodes as a function of the electrode width, gap, and height to determine the optimum geometry. Both the height and the gap between the electrodes were found to have significant effect on the magnitude and distribution of the electric field and current density near the electrode surface, while the width of the electrodes was found to have a smaller effect on field strength and current density. IDEs were fabricated based on these simulations and their performance tested by detecting C-reactive protein (CRP), a stress-related protein and an important biomarker for inflammation, cardiovascular disease risk indicator, and postsurgical recuperation. CRP-specific antibodies were immobilized on the electrode surface and the formation of an immunocomplex (IC) with CRP was monitored. Electrochemical impedance spectroscopy (EIS) was employed as the detection technique. EIS data at various concentrations (1 pg/mL to 10 μg/mL) of CRP spiked in buffer or diluted human serum was collected and fitted into an equivalent electrical circuit model. Change in resistance was found to be the parameter most sensitive to change in CRP concentration. The sensor response was linear from 0.1 ng/mL to 1 μg/mL in both buffer and 5% human serum samples. The CRP samples were validated using a commercially available ELISA for CRP detection. Hence, the viability of IDEs and EIS for the detection of serum biomarkers was established without using labeled or probe molecules.

Keywords

Interdigitated electrodesCRPImpedimetric biosensorEISImpedance spectroscopyDevice simulationLabel-free

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Kanwar Vikas Singh
    • 1
  • Allison M. Whited
    • 1
  • Yaswanth Ragineni
    • 1
  • Thomas W. Barrett
    • 2
  • Jeff King
    • 3
  • Raj Solanki
    • 1
  1. 1.Department of PhysicsPortland State UniversityPortlandUSA
  2. 2.Veterans Affairs and MedicineOregon Health and Science University (OHSU)PortlandUSA
  3. 3.Flash SensortechVirogenomics TigardTigardUSA