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Detection of Molecular Interactions with Modified Ferrocene Self-Assembled Monolayers

2010; American Chemical Society; Volume: 114; Issue: 32 Linguagem: Inglês

10.1021/jp104560e

1520-6106

Man Yi Ho, Peng Li, Pedro Estrela, Sarah A. Goodchild, P. Migliorato,

Advanced biosensing and bioanalysis techniques

Ferrocene-terminated self-assembled monolayers (Fc-SAMs) are one of the most studied molecular aggregates on metal electrodes. They are easy to fabricate and provide a stable and reproducible system to investigate the effect of the microenvironment on the electron transfer parameters. We propose a novel application for Fc-SAMs, the detection of molecular interactions, based on the modification of the SAM with target-specific receptors. Mixed SAMs were fabricated by coimmobilization on Au electrodes of thiolated alkane chains with three different head groups: hydroxy terminating head group, ferrocene head group, and a functional head group such as biotin. Upon binding, the intrinsic electric charge of the target (e.g., streptavidin) modifies the electrostatic potential at the plane of electron transfer, causing a shift in the formal potential E°′. The SAMs were characterized by AC voltammetry. The detection mechanism is confirmed by measurements of formal potential as a function of electrolyte pH.