Immobilization of horseradish peroxidase on nanometre-scale domains of binary self-assembled monolayers formed from dithiobis-N-succinimidyl propionate and 1-tetradecanethiol on Au(111)

Abstract

The nanometre-scale, domain-specific immobilization of horseradish peroxidase (HRP) on binary self-assembled monolayers (SAMs) of dithiobis-N-succinimidyl propionate (DTSP) and 1-tetradecanethiol (TDT) formed on Au(111) has been confirmed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy. After immersing the Au substrates modified with the binary SAMs into an HRP solution, XPS spectra show significant increases in the peak areas of N(1s) and O(1s), indicating the presence of HRP on the surface. After rinsing of the substrate with a KCl solution only covalently immobilized HRP molecules on the domains composed of DTSP remain on the surface. The enzymatic activity of the immobilized HRP is confirmed using cyclic voltammetry in the presence of catechol as an electron transfer mediator.