Consecutive microcontact printing - ligands for asymmetric catalysis in silicon channels
2001 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 79, no 1, 78-84 p.Article in journal (Refereed) Published
Consecutive microcontact printing ( mu CP) has been developed to enable multiple functionalization of silicon surfaces, such as the immobilization of chiral ligands. The technique involves two subsequent printing steps using unstructured poly(methylsiloxane) stamps. The pattern is already defined on the substrate, consisting of etched channels. Hence, no precise alignment is needed between the two printing steps. A carboxylic acid group containing reagent was initially printed onto the silicon oxide surface and transformed to an anhydride. hi the second printing step an ester bond was formed with the hydroxy-functionalized ligand. The formed molecular layers were evaluated by contact angle measurements, scanning electron microscopy (SEM) and electron spectroscopy for chemical analysis (ESCA), indicating that the consecutive mu CP was successful. Initially, printing was performed on planar silicon surfaces but to realize a flow-through microfluidic device for high throughput screening a mu CP technique was developed for etched channels. To verify the technique, hydrophobic valves consisting of octadecyltrichlorosilane were formed using mu CP in deep reactive ion etched channels (50 mum wide and 50 mum deep). The printed hydrophobic patches were visualized by SEM and functioned well. Finally, the consecutive mu CP technique was applied to immobilize the ligand in the channels. The channels were then sealed with a low-temperature bonding technique using an adhesive PDMS film, which does not destroy the printed ligand. In this study mu CP is used in a novel manner. It enables a convenient method for performing complex surface modification of etched structures, which is a frequently appearing problem in biochemical microfluidic systems.
Place, publisher, year, edition, pages
2001. Vol. 79, no 1, 78-84 p.
microcontact printing, chiral ligand, catalysis, solid phase screening, hydrophobic valve, self-assembled monolayers, fabrication, deposition
IdentifiersURN: urn:nbn:se:kth:diva-20946ISI: 000171071300011OAI: oai:DiVA.org:kth-20946DiVA: diva2:339643
QC 201005252010-08-102010-08-10Bibliographically approved