uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Instant oxidation of closed microchannels
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
2007 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 17, no 4, N16-N21 p.Article in journal (Refereed) Published
Abstract [en]

A new method for instant oxidation of closed, bonded microchannels is presented and evaluated. By placing the tip-formed electrode of a corona plasma equipment in the reservoir of a PDMS microstructure, the plasma spark can spread into the microchannel and oxidize the inner PDMS channel walls. By applying this process, the non-specific adsorption of hydrophobic affinity analytes is markedly decreased, here evaluated with the fluorescent dye Rhodamine B and standard protein BSA. The results show that the surface adsorption in plasma-treated channels is reduced significantly, e.g. the amount of BSA adsorbed at 35 mm distance from the reservoir is only 35% of the amount of BSA adsorbed in non-treated channels. The surface shows very low adsorption during the first 200 min after oxidation, and has recovered (90%) its hydrophobicity first after 24 h. This method of instant surface oxidation has in our group been widely used to simplify microfluidic studies of microstructure prototypes, since the need of other more complicated surface modifications to lower analyte adsorption is eliminated.

Place, publisher, year, edition, pages
2007. Vol. 17, no 4, N16-N21 p.
Keyword [en]
Hydrophobicity, Proteins, Hydrophobic compound, Adsorption, Plasma, Dimethylsiloxane polymer, Oxidation, Surface treatments, Fluidics, Microfluidics
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-95131DOI: 10.1088/0960-1317/17/4/N02ISI: 000245434200030OAI: oai:DiVA.org:uu-95131DiVA: diva2:169222
Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2016-04-11Bibliographically approved
In thesis
1. Microfluidics in Surface Modified PDMS: Towards Miniaturized Diagnostic Tools
Open this publication in new window or tab >>Microfluidics in Surface Modified PDMS: Towards Miniaturized Diagnostic Tools
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is a strong trend in fabricating miniaturized total analytical systems, µTAS, for various biochemical and cell biology applications. These miniaturized systems could e.g. gain better separation performances, be faster, consume less expensive reagents and be used for studies that are difficult to access in the macro world. Disposable µTAS eliminate the risk of carry-over and can be fabricated to a low cost.

This work focused on the development of µTAS modules with the intentional use for miniaturized diagnostics. Modules for blood separation, desalting, enrichment, separation and ESI-MS detection were successfully fabricated. Surface coatings were additionally developed and evaluated for applications in µTAS with complex biological samples. The first heparin coating could be easily immobilized in a one-step-process, whereas the second heparin coating was aimed to form a hydrophilic surface that was able to draw blood or plasma samples into a microfluidic system by capillary forces.

The last mentioned heparin surface was further utilized when developing a chip-based sensor for performing CD4-count in human blood, an important marker to determine the stage of an HIV-infection.

All devices in this work were fabricated in PDMS, an elastomeric polymer with the advantage of rapid and less expensive prototyping of the microfabricated master. It was shown that PDMS could be considered as the material of choice for future commercial µTAS. The devices were intentionally produced using a low grade of fabrication complexity. It was however demonstrated that even with low complexity, it is possible to integrate several functional chip modules into a single microfluidic device.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 52 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 241
Materials science, µTAS, micro total analysis system, PDMS, poly(dimethylsiloxane), microfluidics, heparin, blood filtration, on-chip, ESI-MS, desalting, QCM-D, biocompatible, CD4, capillary flow, lab-on-chip, microfabrication, enrichment, point-of-care, hydrophilic, oxidation, Materialvetenskap
urn:nbn:se:uu:diva-7270 (URN)91-554-6716-4 (ISBN)
Public defence
2006-12-08, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30
Available from: 2006-11-17 Created: 2006-11-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Thorslund, SaraNikolajeff, Fredrik
By organisation
Solid State ElectronicsApplied Materials Sciences
In the same journal
Journal of Micromechanics and Microengineering
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 325 hits
ReferencesLink to record
Permanent link

Direct link