An electrochemical-cantilever hybrid sensor for metal ions

In this work we have demonstrated a peptide-functionalized cantilever sensor with integrated electrochemical capabilities. Silicon nitride cantilevers with gold electrodes are functionalized with the chelating peptide Cys-Gly-Gly-His (CGGH) to capture Cu 2+ ions from solution. Upon binding the copper ion the peptide folds, creating steric hindrance and causing compressive stress in the monolayer, deflecting the cantilever downward. Ethylenediaminetetraacetic acid (EDTA) was used to remove the copper ions from the peptide, regenerating the layer. A Cysteine monolayer deflected the cantilever upward with Cu 2+ ions, indicating tensile stress in the layer, suggesting a different coordination scheme than the CGGH peptide layer.