Elastic bounded diffusion and electron propagation: Dynamics of the wiring of a self-assembly of immunoglobulins bearing terminally attached ferrocene poly(ethylene glycol) chains according to a spatially controlled organization

Molecular monolayers of immunoglobulins bearing terminally attached ferrocene poly(ethylene glycol) chains (IgG-PEG-Fc) were self-assembled at an electrode surface in a step-by-step manner involving antigen-antibody recognition reactions. The total number N of assembled IgG-PEG-Fc monolayers and the number of spacers ni separating two successive IgG-PEG-Fc monolayers were controlled and varied. Electron transport through the protein assembly involves the dynamics of the terminally attached PEG chains and isotopic electron exchange between ferrocene heads belonging to successive IgG-PEG-Fc monolayers. The model of elastic bounded diffusion enabled us to analyze quantitatively the dependence of the rate of electron transport on N, n(i), and the rate constant (k(e)) of isotopic electron exchange. Wiring of a molecular monolayer of redox enzyme is also quantitatively characterized.