title: Rapid concentration of deoxyribonucleic acid via Joule heating induced temperature gradient focusing in poly-dimethylsiloxane microfluidic channel.
abstract: This paper reports rapid microfluidic electrokinetic concentration of deoxyribonucleic acid (DNA) with the Joule heating induced temperature gradient focusing (TGF) by using our proposed combined AC and DC electric field technique. A peak of 480-fold concentration enhancement of DNA sample is achieved within 40s in a simple poly-dimethylsiloxane (PDMS) microfluidic channel of a sudden expansion in cross-section. Compared to a sole DC field, the introduction of an AC field can reduce DC field induced back-pressure and produce sufficient Joule heating effects, resulting in higher concentration enhancement. Within such microfluidic channel structure, negative charged DNA analytes can be concentrated at a location where the DNA electrophoretic motion is balanced with the bulk flow driven by DC electroosmosis under an appropriate temperature gradient field. A numerical model accounting for a combined AC and DC field and back-pressure driven flow effects is developed to describe the complex Joule heating induced TGF processes. The experimental observation of DNA concentration phenomena can be explained by the numerical model.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 639798, Singapore.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Ge
authors.affiliation: Singapore Institute of Manufacturing Technology, 638075, Singapore.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 639798, Singapore. Electronic address: mcyang@ntu.edu.sg.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
mesh_terms: D004247:DNA / Q000032:analysis*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004553:Electric Conductivity; D053841:Electroosmosis; D004586:Electrophoresis; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008962:Models, Theoretical; D013997:Time Factors
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon; D004247:DNA
keywords: Deoxyribonucleic acid concentration; Electroosmosis; Electrophoresis; Joule heating; Microfluidics; Temperature gradient focusing