Instant oxidation of closed microchannels

Sara Thorslund*, Fredrik Nikolajeff

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article numberN02
JournalJournal of Micromechanics and Microengineering
Volume17
Issue number4
DOIs
Publication statusPublished - 1 Apr 2007

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