Controlled adsorption of cytochrome c to nanostructured gold surfaces

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Ines Gomes (Author) Other; Maria J Feio (Author) FCUP; Nuno C Santos (Author) Other; Peter Eaton (Author) Other; Ana Paula Serro (Author) Other; Benilde Saramago (Author) Other; Eulalia Pereira (Author) FCUP; Ricardo Franco (Author) Other

Journal

Title: Journal of Nanoparticle Research

Vol. 14 No. 9

Pages: 1-12

ISSN: 1388-0764

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 9 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

Other information

Authenticus ID: P-002-2N2

DOI: 10.1007/s11051-012-1321-7

Abstract (EN): Controlled electrostatic physisorption of horse heart cytochrome c (Cyt c) onto nanostructured gold surfaces was investigated using Quartz-Crystal Microbalance measurements in planar gold surfaces with or without functionalization using a self-assembled monolayer (SAM) of the alkanethiol mercaptoundecanoic acid (MUA). MUA is a useful functionalization ligand for gold surfaces, shedding adsorbed biomolecules from the excessive electron density of the metal. A parallel analysis was conducted in the corresponding curved surfaces of 15 nm gold nanoparticles (AuNPs), using zeta-potential and UV-visible spectroscopy. Atomic Force Microscopy of both types of functionalized gold surfaces with a MUA SAM, allowed for visualization of Cyt c deposits on the nanostructured gold surface. The amount ofCyt c adsorbed onto the gold surface could be controlled by the solution pH. For the assays conducted at pH 4.5, when MUA SAM-functionalized planar gold surfaces are positive or neutral, and Cyt c has a positive net charge, only 13 % of the planar gold surface area was coated with protein. In contrast, at pH 7.4, when MUA SAM-functionalized planar gold surfaces and Cyt c have opposite charges, a protein coverage of 28 % could be observed implying an adsorption process strongly governed by electrostatic forces. Cyt c adsorption on planar and curved gold surfaces are found to be greatly favored by the presence of a MUA-capping layer. In particular, on the AuNPs, the binding constant is three times larger than the binding constant obtained for the original citrate-capped AuNPs.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12