Jung Woo Hong

Publications (3)10.22 Total impact

• Source

  Available from: Hyun C Yoon

  Article: Fluorescence affinity sensing by using a self-contained fluid manoeuvring microfluidic chip.

  Jung Woo Hong, Kwang Hyo Chung, Hyun C Yoon
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  ABSTRACT: An application of a novel polymer microfluidic chip for sample exchange via natural capillary forces for immuno-analysis is described. The microfluidic device was designed to achieve sample replacement by capillary force only, which would therefore be suitable for point-of-care-testing. Complete and automatic replacement of the sample in the reaction chamber with another one makes the chip able to mimic affinity chromatography and immunoassay processes. The microfluidic chip was made using polymer replication techniques, which were suitable for fast and cheap fabrication. Micrometre-sized polystyrene beads were used for the functionalization of biomolecules. Dinitrophenyl (DNP) and anti-DNP antibody coordination was employed on the chip for fluorescence analysis. DNP was immobilized on the polymer beads via a pre-adsorbed dendrimer layer and the beads were placed in the reaction chamber. Fluorescein tagged anti-DNP was successfully observed by a fluorescence microscope after the completion of the entire flow sequence. A calibration curve was registered based on the anti-DNP concentration. A multiplex sensing was accomplished by adding biotin/streptavidin coordination to the system. DNP and biotin conjugated beads were placed in the reaction chamber in an ordered fashion and biospecific bindings of anti-DNP antibody and streptavidin were observed at their expected sites. A ratiometric analysis was carried out with different concentration ratios of anti-DNP/streptavidin. The microfluidic chip described in this work could be applied to various biological and chemical analyses using integrated washing steps or fluid replacement steps with minimum sample handling.
  The Analyst 05/2008; 133(4):499-504. · 4.23 Impact Factor
• Source

  Available from: Hyun C Yoon

  Article: Microfluidic chip accomplishing self-fluid replacement using only capillary force and its bioanalytical application.

  Kwang Hyo Chung, Jung Woo Hong, Dae-Sik Lee, Hyun C Yoon
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  ABSTRACT: A polymer microfluidic chip accomplishing automated sample flow and replacement without external controls and an application of the chip for bioanalytical reaction were described. All the fluidic operations in the chip were achieved by only natural capillary flow in a time-planned sequence. For the control of the capillary flow, the geometry of the channels and chambers in the chip was designed based on theoretical considerations and numerical simulations. The microfluidic chip was made by using polymer replication techniques, which were suitable for fast and cheap fabrication. The test for a biochemical analysis, employing an enzyme (HRP)-catalyzed precipitation reaction, exhibited a good performance using the developed chip. The presented microfluidic method would be applicable to biochemical lab-on-a-chips with integrated fluid replacement steps, such as affinity elution and solution exchange during biosensor signaling.
  Analytica chimica acta 03/2007; 585(1):1-10. · 4.31 Impact Factor
• Article: A new immunosensing method by galactose oxidase-mediated electrocatalysis using a virtual beaker array.

  Sung Il Jeon, Jung Woo Hong, Hyun C Yoon
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  ABSTRACT: We report a novel and convenient method for the determination of glycoproteins, especially antibodies, using galactose oxidase (GAO) on the basis of the contents of galactosyl and N-acetylgalactosaminyl residues in carbohydrate chains of glycoproteins. GAO converts galactose residues to their corresponding aldehyde and H(2)O(2), the latter being electroactive and quantifiable by DC amperometry. The method does not require processes such as antibody labeling or the use of enzyme-tagged secondary antibodies. For an array-type immunosensing, the platform surface for antigen immobilization was specially designed by using differentiated surface wetting property of hydrophobic and hydrophilic patterns. We patterned the hydrophobic surface of the poly(dimethylsiloxane) substrate by microcontact printing with the poly(amidoamine) dendrimer ink, providing hydrophilic patterns on a hydrophobic base substrate. By applying aqueous solution on the patterned surface, an array of free-standing water droplets was made. With the prepared virtual beaker array, electrochemical immunosensing was performed by using anti-dinitrophenyl-IgG as a model target protein. From immunoassay with GAO-mediated electrocatalysis, a good correlation in amperometric signal with the target IgG was registered. The total assay time was about 20 min, including antibody recognition and signal registration.
  Biotechnology Letters 10/2006; 28(17):1401-8. · 1.68 Impact Factor