In present study, stretching dynamics of electrically tethered λ-DNA (48.5kbp) in SiO2 nanochannels has been investigated. At high electrical fields (above 20kV/m), elongations of electrically tethered DNA molecules were observed. At high E-fields, DNAs were tethered in nanochannels and were spontaneously elongated along the nanochannels up to about 90 percent of its contour length. With E-field turned off, the measured relaxation time was about 10 sec from stretching with 20kV/m. In current study, observed behaviors of DNA molecules in nanochannels were explained by field-induced dielectrophoretic DNA trap due to the particular cross-sectional geometry of nanochannels. Also the elongation ratio between 20kV/m and 60kV/m cases and the effect of E-field distribution in the transverse plane on fieldinduced dielectrophoretic tethering force are discussed based on “worm-like chain” model. The FEM simulation was done to verify induced dielectrophoretic tethering force into the nanohorn.
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