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)

The nanometre-scale, domain-specific immobilization of horseradish peroxida se (HRP) on binary self-assembled monolayers (SAMs) of dithiobis-N-succinim idyl propionate (DTSP) and 1-tetradecanethiol (TDT) formed on Au(111) has b een confirmed by X-ray photoelectron spectroscopy (XPS) and atomic force mi croscopy. After immersing the Au substrates modified with the binary SAMs i nto an HRP solution, XPS spectra show significant increases in the peak are as of N(1s) and O(1s), indicating the presence of HRP on the surface. After rinsing of the substrate with a KCI solution only covalently immobilized H RP molecules on the domains composed of DTSP remain on the surface. The enz ymatic activity of the immobilized HRP is confirmed using cyclic voltammetr y in the presence of catechol as an electron transfer mediator.