Redox Actuation of Microcantilevers Functionalized with Ferrocenyldodecanethiolate Self-Assembled Monolayer: Effect of the Surface Composition and Molecular Clustering

The detection and quantification of trace levels of (bio-)molecules in a complex matrix constitute an important challenge in (bio-)analytical chemistry. Adavances in microfabrication and surface functionalisation chemistry are providing the sensitivity to overcome this challenge. Microcantilevers are highly flexible devices capable of transducing very small physical changes induced by (bio-)chemical reactions into a mechanical motion. Briefly, microcantilever sensors work as follows: the microcantilever is modified with a reactive self-assembled monolayer (SAM). Binding of the analyte to the reactive groups in the monolayer induces intermolecular forces that result in a differential surface stress change and a vertical deflection or bending of the cantilever. The magnitude of the deflection, typically on the nanometer to micron scale, depends on the analyte concentration. Detection limits as low as ppt (10 level) have been reported. These are potentially good candidates for the label-free in-situ detection of biomolecules and biomolecular interactions.