Lookup NU author(s): Dr Ben Horrocks,
Professor Andrew Houlton,
Professor Jeremy Lakey
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We present a straightforward strategy to control the average distance of immobilized biomolecules on silicon surfaces. We exploit the reaction taking place between the amino residues within the biomolecules (lysine groups of proteins or the N-terminus of oligomers of peptide nucleic acid, PNA) and the aldehyde-terminated groups presented in a mixed aldehyde/alkyl organic monolayer on a silicon surface. The mixed monolayers were prepared by a thermal reaction of hydrogen-terminated Si(111) with a mixture of undecene and undecenyl-aldehyde. We quantitatively evaluate the surface concentration of aldehyde in the monolayer by atomic force microscopy and an intensity analysis of core level X-ray photoemission spectroscopy peaks. These complementary techniques show that the surface density of the reactive terminal groups reflects the mole fraction of aldehyde in the reactive solution used to modify the silicon surface. The further immobilization of proteins or peptide nucleic acids on the monolayer shows that the density of biomolecules reproduces the aldehyde surface density, which indicates a specific covalent attachment and a negligible nonspecific adsorption. The proposed procedure makes possible to control the average distance of the immobilized active biomolecules on the silicon surface, which could be of great relevance for applications in the interdisciplinary field of biosensors.
Author(s): Rogero C, Chaffey BT, Mateo-Martí E, Sobrado JM, Horrocks BR, Houlton A, Lakey JH, Briones C, Martín-Gago JA
Publication type: Article
Publication status: Published
Journal: Journal of Physical Chemistry C
ISSN (print): 1932-7447
ISSN (electronic): 1932-7455
Publisher: American Chemical Society
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