Analytical and Bioanalytical Chemistry

, Volume 405, Issue 20, pp 6425–6436

Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices

  • A. Poghossian
  • M. Weil
  • A. G. Cherstvy
  • M. J. Schöning
Research Paper

DOI: 10.1007/s00216-013-6951-9

Cite this article as:
Poghossian, A., Weil, M., Cherstvy, A.G. et al. Anal Bioanal Chem (2013) 405: 6425. doi:10.1007/s00216-013-6951-9

Abstract

The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte–insulator–semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance–voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.

Figure

Label-free electrical monitoring of polyelectrolyte multilayer formation by means of a capacitive field-effect sensor consisting of Al-p-Si-SiO2 structure. The consecutive adsorption of oppositely charged polyelectrolyte layers leads to alternating shifts of the capacitance-voltage and constant-capacitance curves, whereas the direction of these shifts correlates with the charge sign of the terminating polyelectrolyte layer

Keywords

Field-effect Capacitive sensor Polyelectrolyte multilayer Electrical monitoring ConCap 

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • A. Poghossian
    • 1
    • 3
  • M. Weil
    • 1
    • 2
  • A. G. Cherstvy
    • 4
    • 5
  • M. J. Schöning
    • 1
    • 3
  1. 1.Institute of Nano- and Biotechnologies (INB)Aachen University of Applied Sciences, Campus JülichJülichGermany
  2. 2.Department of Informatics and Microsystem TechnologyUniversity of Applied Sciences Kaiserslautern, Campus ZweibrückenKaiserslauternGermany
  3. 3.Peter Grünberg Institute (PGI-8), Research Centre Jülich GmbHJülichGermany
  4. 4.Max-Planck Institute for the Physics of Complex SystemsDresdenGermany
  5. 5.Institute for Physics and AstronomyUniversity of PotsdamPotsdamGermany

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