Characterization of the substructure and properties of immobilized peptides on silicon surface

• Published in: Materials chemistry and physics Vol. 126; no. 3; pp. 955 - 961
• Main Authors: Shamsi, Fahimeh, Coster, Hans, Jolliffe, Katrina A., Chilcott, Terry
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.04.2011
• Subjects: Attachment; Biosensors; Biotechnology; Esters; Nanotechnology; Peptides; Self-assembled monolayer; Silicon; Spectroscopy; Succinimides; Surface chemistry; X-ray photoelectron spectroscopy; Biotechnology; Self-assembled monolayer; Biosensors; Nanotechnology
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2010.11.058

▶ Self-assembled monolayers were produced of N-decanoic acid covalently linked to the [1 1 1] surface of a silicon wafer. ▶ The acid terminated monolayers were converted to the N-hydroxy succinimide esters and the biologically active peptide, (A-A-A-A-G-G-E_R_G-D) was then attached this functionalized surface. ▶ The structure and composition of these films were determined using very high resolution electrical impedance spectroscopy, XPS and FITR. ▶ Attachment of the peptide at pH 7 yielded films that were densely packed with the peptide oriented normal to the surface. Attachment at pH 4 in contrast yieldedless densely packed, thinner, films, suggesting an orientation of the peptides un the plane of the surface. Immobilization of biomaterials onto solid supports is a means of functionalizing materials for applications such as biosensing. Biologically active peptide (A-A-A-A-G-G-G-E-R-G-D) 1 1 A: Alanine E: Glutamic acid D: Aspartic acid G: Glycine R: Arginine. films were attached to N-hydroxy succinimide ester terminated self-assembled monolayers (SAM) which were covalently linked to a smooth silicon surface via Si–C bonds. The peptide films were characterized using electrical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The film structures were determined from examination of the capacitance and conductance dispersions with frequency. Analysis of XPS, EIS and FTIR after immobilization of the peptide film at pH 4 and 7 provided information on the extent of the activation and overall coupling efficiencies of the peptides to the N-hydroxy succinimide ester surface. The resulting film structure was markedly altered by attachment of the peptide at pH 4.