title: Measuring single-bond rupture forces using high electric fields in microfluidic channels and DNA oligomers as force tags.
abstract: The disruption force of specific biotin-streptavidin bonds was determined using DNA oligomers as force tags. Forces were generated by an electric field acting on a biotinylated fluorescently labeled DNA oligomer. DNA oligomers were immobilized via biotin-streptavidin bonds on the walls of microfluidic channels. Channel layout and fluid-based deposition process were designed to enable well-defined localized deposition of the oligomers in a narrow gap of the microchannel. Electric fields of up to 400 V/cm were applied and electric field induced desorption of DNA oligomers was observed. At T approximately 30 degrees C, field-induced desorption of both a 12 mer as well as a 48 mer yielded a streptavidin-biotin disruption force of 75 fN. Streptavidin-functionalized surfaces remained intact and could be reloaded with biotinylated oligomers. At approximately 20 degrees C, however, no field-induced unbinding of the oligomers was observed at electric field strength of up to 400 V/cm, indicating a significant temperature dependence of the bond strength.
authors.affiliation: Naturwissenschaftliches und Medizinisches Institut, 72770 Reutlingen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Breisch
authors.forename: Julian
authors.initials: J
authors.lastname: Gonska
authors.forename: Helmut
authors.initials: H
authors.lastname: Deissler
authors.forename: Martin
authors.initials: M
authors.lastname: Stelzle
mesh_terms: D001703:Biophysics / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D019921:Biotinylation; D004247:DNA / Q000737:chemistry*; D004560:Electricity; D008055:Lipids / Q000737:chemistry; D019563:Mechanics; D044085:Microfluidics / Q000379:methods*; D008856:Microscopy, Fluorescence; D011312:Pressure; D055672:Static Electricity; D019809:Streptavidin / Q000737:chemistry; D013696:Temperature
chemical_list: D008055:Lipids; D001710:Biotin; D004247:DNA; D019809:Streptavidin