Microfabricated Porous Membrane Structure for Sample Concentration and Electrophoretic Analysis

• Published in: Analytical chemistry (Washington) 1999-05, Vol.71 (9), p.1815-1819
• Main Authors: Khandurina, Julia, Jacobson, Stephen C, Waters, Larry C, Foote, Robert S, Ramsey, J. Michael
• Format: Article
• Language: English
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Chemistry; Deoxyribonucleic acid; DNA; DNA - analysis; Electrophoresis - instrumentation; Electrophoresis - methods; Fluorescence; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; Membranes, Artificial; Nucleic acids; Polymerase Chain Reaction
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac981161c

A microfabricated injection valve incorporating a porous membrane structure is reported that enables electrokinetic concentration of DNA samples using homogeneous buffer conditions followed by injection into a channel for electrophoretic analysis. The porous membrane was incorporated in the microchannel manifold by having two channels separated from each other by 3−12 μm and connected by a thin porous silicate layer. This design allows the passage of current to establish an electrical connection between the separated channels but prevents large molecules, e.g., DNA, from traversing the membrane. Concentrated DNA can be injected into the separation channel and electrophoretically analyzed. Experiments exhibit a nonlinear increase in concentration with time, and DNA fragments can be concentrated up to 2 orders of magnitude as shown by comparison of peak intensities for analysis performed with and without concentration.