title: Functional membrane-implanted lab-on-a-chip for analysis of percent HDL cholesterol.
abstract: A functional lab-on-a-chip has been developed for simultaneous quantitative analyses of high-density lipoprotein (HDL) cholesterol (HDL-C) and total cholesterol (total-C) in a submicroliter plasma sample. The analytical device was fabricated by placing commercial membranes, traditionally used for rapid diagnostics, within microfluidic channels engraved on the surface of a plastic chip. The concentration of HDL-C was measured using enzymatic reactions to produce a colorimetric signal after separation of the single plasma lipoprotein from a mixture. Two small pieces of different membrane pads were used to provide each group of reagents, for HDL separation and enzyme reactions, deposited within their tiny pores in a dry state. To maintain a connection toward the capillary action of the medium, the pads were arranged in a sequence within the fluidic channel that controlled the inlet and outlet of the flow. Upon the addition of a sample, the fluid was delivered through the pads of the chip and a color signal was subsequently generated in proportion to the concentration of HDL-C. The level of total-C was concurrently determined by following identical processes, except absent HDL separation. The two signals were simultaneously determined by employing optical detectors based on transmittance of a light. Such total analyses were completed within 2 min, and the sample sizes were able to be reduced to 0.4 microL for HDL-C and 0.1 microL for total-C, enough to cover the clinically required dynamic ranges.
authors.affiliation: Graduate School of Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-ku, Seoul 136-701, Korea.
authors.forename: Joo-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Joung-Hwan
authors.initials: JH
authors.lastname: Cho
authors.forename: Se-Hwan
authors.initials: SH
authors.lastname: Paek
mesh_terms: D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008567:Membranes, Artificial; D046208:Microchip Analytical Procedures / Q000379:methods
chemical_list: D008076:Cholesterol, HDL; D008567:Membranes, Artificial; D002784:Cholesterol