Gold nanoparticle‐modified capacitive field‐effect sensors: Studying the surface density of nanoparticles and coupling of charged polyelectrolyte macromolecules

Electrochemical Science Advances, vol. 2

Abstract

Abstract The coupling of ligand‐stabilized gold nanoparticles with field‐effect devices offers new possibilities for label‐free biosensing. In this work, we study the immobilization of aminooctanethiol‐stabilized gold nanoparticles (AuAOTs) on the silicon dioxide surface of a capacitive field‐effect sensor. The terminal amino group of the AuAOT is well suited for the functionalization with biomolecules. The attachment of the positively‐charged AuAOTs on a capacitive field‐effect sensor was detected by direct electrical readout using capacitance‐voltage and constant capacitance measurements. With a higher particle density on the sensor surface, the measured signal change was correspondingly more pronounced. The results demonstrate the ability of capacitive field‐effect sensors for the non‐destructive quantitative validation of nanoparticle immobilization. In addition, the electrostatic binding of the polyanion polystyrene sulfonate to the AuAOT‐modified sensor surface was studied as a model system for the label‐free detection of charged macromolecules. Most likely, this approach can be transferred to the label‐free detection of other charged molecules such as enzymes or antibodies.

Authors 5

1. Tobias Karschuck Aachen

   FH Aachen

   Affiliation as printed

   Institute of Nano‐ und Biotechnologies Aachen University of Applied Sciences Jülich Germany

2. Corinna Kaulen Aachen

   FH Aachen

   Affiliation as printed

   Institute of Nano‐ und Biotechnologies Aachen University of Applied Sciences Jülich Germany

3. Arshak Poghossian corresponding
   Affiliation as printed

   MicroNanoBio Düsseldorf Germany

4. Patrick Hermann Wagner

   KU Leuven

   Affiliation as printed

   Laboratory for Soft Matter and Biophysics KU Leuven Leuven Belgium

   Laboratory for Soft Matter and Biophysics, KU Leuven, Leuven, Belgium

5. Michael Josef Schöning corresponding Aachen

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Institute of Biological Information Processing (IBI‐3) Forschungszentrum Jülich Jülich Germany

   Institute of Nano‐ und Biotechnologies Aachen University of Applied Sciences Jülich Germany