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

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 aminooctanethiol-stabilized (AuAOTs) on silicon dioxide surface a capacitive sensor. terminal amino group AuAOT is well suited functionalization biomolecules. attachment positively-charged AuAOTs sensor was detected by direct electrical readout using capacitance-voltage and constant capacitance measurements. With higher particle density surface, measured signal change correspondingly more pronounced. results demonstrate ability sensors non-destructive quantitative validation nanoparticle immobilization. addition, electrostatic binding polyanion polystyrene sulfonate to AuAOT-modified studied as model system detection charged macromolecules. Most likely, approach can be transferred other molecules such enzymes or antibodies.