Some Concluding Observations and Outlooks

The weaker contrast which also displayed contrast fluctuations in time was assigned to the AuNP-azurin hybrid, the stronger robust contrast to individual AuNPs or azurin molecules. 

AuNPs inserted between the electrode surface and redox metalloproteins therefore both work as effective molecular linkers and exert eflfident electrocatalysis. Recent considerations based on resonance turmeling between the electrode and the molecule via the AuNP as a mechanism for enhanced interfadal ET rates suggest that electronic spillover rather than energetic resonance is a hkely origin of the effects (J. Kleis et al., work in progress). Even slightly enhanced spillover compared with a planar Au(lll) surface is enough to enhance the ET rate by the observed amount over a 10-15 A ET distance. 

Single-crystal, atomically planar electrode surfaces have paved the way for introducing the scanning probe microscopies of STM and AFM in the bioelectrochemical sciences. The powerful in situ STM technology has increased the structural resolution of (bio)electrochemical electrode surfaces to the molecular and 

Electronic conductivity of molecules including redox metalloproteins with accessible low-lying redox states in nanogap electrode configurations or in situ STM displays quite different patterns. These are dominated by sequential two-step (or multiple-step) hopping through the redox center, induced both by potential variation and environmental configurahonal fluctuations. Both redox molecules and 

This work was supported financially by the Danish Research Council for Technology and Production Sciences, the Lundbeck Foundation, and the Villum Kann Rasmussen Foundation. 

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