Head-group charge, modification

Another possibility to keep the distance between an immobilized redox protein and an electrode surface small is seen in using SAMs for modification of mostly Au electrodes. SAM provides an interface with specific functions such as functional head-groups for binding of proteins, suitable charges for anisotropic orientation of proteins, and often they prevent denaturation of the proteins. Astonishingly, even direct electron transfer from SAM-immobilized glucose oxidase has been proved, although the mechanism remains unclear [181]. 

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