Electric field isolator (EFI) for isolated and electrophoretic manipulation of charged biomolecules

Yun, Jae Young; Mun, Sang Jun; Lee, Seung Seob; Nam, Hong Gil

doi:10.1039/b618099j

Cited by 2 publications

(1 citation statement)

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“…The use of an electric-field isolator (EFI) was an alternative technique that enabled isolation of DNA inside a selected location, thus concentrating the DNA. 30 These approaches require micro-or nano-structures, a porous medium, gels, highly viscous polymer solutions, microbeads or magnetic beads to concentrate or to purify DNA within a biological sample in a microchannel, indicating that concentration or purification of DNA is quite difficult in free solution. 19 Despite these approaches being effective, underlying drawbacks exist such as the complicated fabrication required for an entire device or platform, a large loss of pressure caused by solid obstacles or filled materials, a burdensome procedure and external fields (electric or magnetic field) involved in a continuous separation.…”

Section: Introductionmentioning

confidence: 99%

Locally enhanced concentration and detection of oligonucleotides in a plug-based microfluidic device

et al. 2012

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We propose a novel technique that allows oligonucleotides with specific end-modification within a plug in a plug-based microfluidic device to undergo a locally enhanced concentration at the rear of the plug as the plug moves downstream. DNA was enriched and detected in situ upon exploiting a combined effect underlain by an entropic force induced through fluid shear (i.e. a hydrodynamic-repellent effect) and the interfacial adsorption (aqueous/oil interface) attributed to affinity. Flow fields within a plug were visualized quantitatively using micro-particle image velocimetry (micro-PIV); the distribution of the fluid shear strain rate explains how the hydrodynamic-repellent effect engenders a dumbbell-like region with an increased concentration of DNA. The concentration of FAM (6-carboxy-fluorescein)-labeled DNA (FC-DNA) and of TAMRA (tetramethyl-6-carboxyrhodamine)-labeled DNA (TC-DNA), respectively, and the hybridization of probe DNA (modified with FAM) with target DNA (modified with TAMRA) were investigated in devices; a confocal fluorescence microscope (CFM) was utilized to monitor the processes and to resolve the corresponding 2D patterns and 3D reconstruction of the DNA distribution in a plug. TC-DNA, but not FC-DNA, concentrating within a plug was affected by the combined effect so as to achieve a concentration factor (C(r)) twice that of FC-DNA because of the lipophilicity of TAMRA. Using fluorescence resonance-energy transfer (FRET), we characterized the hybridization of the DNA in a plug; the detection limit of a system, improved by virtue of the proposed technique (the locally enhanced concentration), for DNA detection was estimated to be 20-50 nM. This technique enables DNA to concentrate locally in a nL-pL free-solution plug, the locally enhanced concentration to profit the hybridization efficiency and the detection of DNA, prospectively serving as a versatile means to accomplish a rapid DNA detection in a small volume for a Lab-on-a-Chip (LOC) system.

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Section: Introductionmentioning

confidence: 99%