Characterising the formation of a bioelectrochemical interface at a self-assembled monolayer using X-ray photoelectron spectroscopy

In this paper, we characterise the process of immobilisation of cytochrome c at a gold surface modified with the short chain alkyl-thiol self-assembled monolayer, mercaptopropionic acid. Using high resolution X-ray photoelectron spectroscopy, we reveal detail of the step-by-step construction of the biomolecular structure at a self-assembled monolayer, measured during two different immobilisation protocols involving either a carbodiimide activated intermediate or aminolysis of a succinimide ester by the protein. Finally, we relate the subtle variations in the charged species produced during the immobilisation procedures to differences that we measure in the protein's redox potential. (C) 1997 Elsevier Science S.A.