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Surface Functionalization of Silicon Oxide at Room Temperature and Atmospheric Pressure
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Surface Biotechnology.
2002 In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 254, no 1, 200-203 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2002. Vol. 254, no 1, 200-203 p.
URN: urn:nbn:se:uu:diva-90666OAI: oai:DiVA.org:uu-90666DiVA: diva2:163109
Available from: 2003-09-01 Created: 2003-09-01Bibliographically approved
In thesis
1. Spatially Controlled Covalent Immobilization of Biomolecules on Silicon Surfaces
Open this publication in new window or tab >>Spatially Controlled Covalent Immobilization of Biomolecules on Silicon Surfaces
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The work described in this thesis aims to achieving surface patterning through chemical activation of thiolated silicon oxide surfaces, resulting in a spatially controlled covalent immobilization of biomolecules with high resolution.

Existing chemical methods to immobilize molecules on surfaces do not reach below the micrometer scale while the ones allowing for spatial control mostly lead to non-covalent adsorption of molecules on surfaces, or require several successive chemical reactions to obtain the final covalent immobilization. Methods with improved chemical processes and novel surface modification techniques had to be developed.

A basic need for studying interactions of biomolecules on chemically modified surfaces with high resolution is the ability to obtain a simple, inexpensive method resulting in ultraflat densely packed and reproducible organic monolayers. Therefore, a new method for silicon oxide chemical derivatization, fulfilling these requirements, was developed.

Thiol derivatized silicon oxide surfaces allow for a diversity of activation reactions to occur, resulting in thiol-disulfide exchange. The electrooxidation of surface-bound thiol groups was investigated as a way of generating reactive thiolsulfinates/thiolsulfonates, by application of a positive potential difference to the silicon surfaces. Peptide molecules containing thiol groups were successfully immobilized to the electroactivated surfaces. In addition, this new chemical activation method offers the possibility to release the bound molecules in order to regenerate the surfaces. Subsequently, the thiolated surfaces can be reactivated for further use.

Since the activated area depends directly on the size of the electrodes used for the oxidation, nanoscale activation of the thiolated surfaces was performed by use of an AFM tip as counter-electrode. Electrooxidized patterns, with a line width ranging from 70 nm to 200 nm, were obtained. A thiol-rich protein, b-galactosidase, was selectively immobilized onto the electroactivated patterns.

An electrochemical version of microcontact printing was developed in order to activate large surface areas with micrometer scale patterns. Conductive soft polymer stamps were produced using an evaporated aluminum coating. Patterned electroactivation of thiols was achieved, and polystyrene beads were subsequently specifically immobilized onto the patterns.

As a conclusion, these different projects resulted in a strategy enabling the achievement of nanoscale and microscale positioning and immobilization of biomolecules on silicon surfaces, with potential reversibility and reuse of the surfaces.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2003. 57 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 867
Biotechnology, silicon oxide, electrooxidation, sulfur, nanotechnology, self-assembled monolayers, atomic force microscopy, electron spectroscopy for chemical analysis, biomolecules, covalent immobilization, reversibility, Bioteknik
National Category
Industrial Biotechnology
urn:nbn:se:uu:diva-3523 (URN)91-554-5691-X (ISBN)
Public defence
2003-10-03, B 22, Biomedical Center, Husargatan 3, Uppsala, 12:00
Available from: 2003-09-01 Created: 2003-09-01Bibliographically approved

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