The adsorption of the
proteins CD13,
mucin and
bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6](3-/4-). The hydrophobicity of the Au surface was tailored using specific
peptides, blocking agents and diluents. The combination of blocking agents (
ethanolamine or
n-butylamine) and diluents (hexanethiol or
2-mercaptoethanol) was used to prepare various
peptide-modified Au surfaces.
Protein adsorption onto the
peptide-Au surfaces modified with the combination of
n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three
proteins. In contrast, polar
peptide-surfaces induced a minimal change in Rct for all three
proteins. Furthermore, an increase in Rct was observed with CD13 (an
aminopeptidase overexpressed in certain
cancers) in comparison to the other
proteins when the VLGXE-Au surface was modified with
n-butylamine as a blocking agent. The electrochemical data indicated that
protein adsorption may be modulated by tailoring the
peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing
protein adsorption. The
peptide-Au platform may also be used for targeting
cancer biomarkers with designer
peptides.