title: Separation of single-stranded DNA fragments at a 10-nucleotide resolution by stretching in microfluidic channels.
abstract: We report a novel DNA separation method by tethering DNA chains to a solid surface and then stretching the DNA chains with an electric field. The anchor is such designed that the critical force to detach a DNA chain is independent of its size. Because the stretching force is proportional to the DNA net charge, a gradual increase of the electric field leads to size-based removal of the DNA strands from the surface and thus DNA separation. Here we show that this method, originally proposed for separation of long double-stranded DNA chains (>10,000 base pairs), is also applicable to single-stranded (ss) DNA fragments with less than 100 nucleotides (nt). Theoretical analysis indicates that the separation resolution is limited by the fluctuation forces on tethered DNA chains. By employing a microfluidic platform with narrow channels filled with a buffer of low ionic conductivity, we are able to apply a strong electric field to the DNA fragments with negligible Joule heating. Upon stepwise increments of the electric field, we demonstrate efficient separation of short ssDNA fragments at a 10-nt resolution.
authors: Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors: Jiamin
authors: J
authors: Wu
authors: Shuang-Liang
authors: SL
authors: Zhao
authors: Lizeng
authors: L
authors: Gao
authors: Jianzhong
authors: J
authors: Wu
authors: Di
authors: D
authors: Gao
mesh_terms: D001710:Biotin / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000302:isolation & purification*; D004560:Electricity; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D009711:Nucleotides / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry; D013499:Surface Properties
chemical_list: D004277:DNA, Single-Stranded; D009711:Nucleotides; D001710:Biotin; D019809:Streptavidin