Measuring Single-Bond Rupture Forces Using High Electric Fields in Microfluidic Channels and DNA Oligomers as Force Tags

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• 作者：Stefanie Breisch ; Julian Gonska ; Helmut Deissler ; Martin Stelzle
• 刊名：Biophysical Journal
• 出版年：2005
• 出版时间：September 2005
• 年：2005
• 卷：89
• 期：3
• 页码：L19-L21
• 全文大小：190 K

文摘

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 ≈ 30°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 ≈20°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.