Molecular recognition is the key feature of bioinspired sensor applications. A profound understanding of recognitive binding events is crucial for the design of highly specific and effective binding molecules. In this paper a series of simple to complex oligopeptides, derived from the Ca2+ chelator ethylenediaminetetraacetic acid (EDTA) and the Ca2+ binding protein calmodulin, were investigated. It was shown, that specifically designed oligopeptides can fulfil protein-like recognition functions but are much easier to immobilize and enable high functional integration. Impedance spectroscopy (IS) could be used to detect binding of Ca2+ to different peptides because the double layer capacitance is highly sensitive to changes in the morphology and dielectric properties of adsorbate layers. Finally, the designed functional oligopeptides were implemented in silicon nanowire field effect transistors (SiNW FETs) as a proof of concept for future problem-optimized molecules in sensor devices.
The graph shows frequency-normalized admittance plots and corresponding schemes of a peptide monolayers layer before and after binding of Ca2+ ions.