Lateral migration and focusing of colloidal particles and DNA molecules under viscoelastic flow.
Summary of "Lateral migration and focusing of colloidal particles and DNA molecules under viscoelastic flow."
Much difficulty has been encountered in manipulating small-scale materials, such as submicron colloidal particles and macromolecules (e.g., DNA and proteins), in microfluidic devices since diffusion processes due to thermal (Brownian) motion become more pronounced with decreasing particle size. Here, we present a novel approach for the continuous focusing of such small-scale materials. First, we successfully focused fluorescent submicron polystyrene (PS) beads along equilibrium positions in microchannels through the addition of a small amount water-soluble polymer [500 ppm poly(ethylene oxide) (PEO)]. Lateral migration velocity significantly depends upon the viscoelastic effect (Weissenberg number: Wi) and the aspect ratio of particle size to channel height (a/h). Interestingly, focusing using viscoelastic flows was also observed for flexible DNA molecules (λ-DNA and T4-DNA), which have radii of gyration (R(g)) of approximately 0.69 μm and 1.5 μm, respectively. This small-scale material manipulation using medium viscoelasticity will contribute to the design of nanoparticle separation and genomic mapping devices.
Affiliation
Department of Chemical Engineering, Ajou University, Suwon 443-749, Republic of Korea. jumin@ajou.ac.kr.
Journal Details
This article was published in the following journal.
Name: Lab on a chip
ISSN: 1473-0189
Pages: 2807-14
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22776909
- DOI: http://dx.doi.org/10.1039/c2lc40147a
Medical and Biotech [MESH] Definitions
Fractionation, Field Flow
Separation of molecules and particles by a simultaneous action of carrier liquid flow and focusing field forces (electrical, sedimentation, or thermal), without a stationary phase.
Electrophoresis
An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.
Serum Albumin
A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.
Cell Migration Inhibition
Phenomenon of cell-mediated immunity measured by in vitro inhibition of the migration or phagocytosis of antigen-stimulated LEUKOCYTES or MACROPHAGES. Specific CELL MIGRATION ASSAYS have been developed to estimate levels of migration inhibitory factors, immune reactivity against tumor-associated antigens, and immunosuppressive effects of infectious microorganisms.
Elementary Particle Interactions
The interactions of particles responsible for their scattering and transformations (decays and reactions). Because of interactions, an isolated particle may decay into other particles. Two particles passing near each other may transform, perhaps into the same particles but with changed momenta (elastic scattering) or into other particles (inelastic scattering). Interactions fall into three groups: strong, electromagnetic, and weak. (From McGraw-Hill Encyclopedia of Science & Technology, 7th ed)
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