Woo-Jae Chung

Sungkyunkwan University, Sŏul, Seoul, South Korea

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Publications (27)53.45 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A facile simple preparation of polymer-supported IBX amide (IBX amide resin) from chloromethyl polystyrene resin was demonstrated. The IBX amide resins were prepared with high loading levels (∼1.40 mmol g−1). These reagents were found to be mild and efficient oxidants through oxidation of a range of alcohols, sulfides and phosphites to the corresponding carbonyl, sulfoxide and phosphate compounds without over-oxidation at room temperature. Consumed IBX amide resins were reused up to five times without significant loss of oxidative activity after repetitive regeneration.
    Journal of Industrial and Engineering Chemistry. 01/2014; 20(1):29–36.
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    ABSTRACT: The molecular mechanisms underlying the non-opsonic phagocytosis of bacteria by neutrophils are poorly understood. We previously reported the efficient uptake of Streptococcus sanguinis by human neutrophils in the absence of opsonins. To characterize the phagocytosis receptor, protein lysates from neutrophils and HL-60 cells were subjected to affinity chromatography using epoxy beads coated with S. sanguinis. Denaturing electrophoresis of the eluted proteins and subsequent mass spectrometry revealed that one of the proteins eluted from neutrophils was proteinase 3 (PR3). Enzymatic cleavage of the glycosylphosphatidylinositol linker of NB1, a co-receptor for membrane-bound PR3 (mPR3), significantly reduced the phagocytosis of S. sanguinis. In addition, the neutralization of mPR3 with antibody reduced both binding and phagocytosis of S. sanguinis. Treatment of neutrophils with a serine proteinase inhibitor indicated that protease activity is required for phagocytosis. Thus, we studied whether protease-activated receptor 2 (PAR2) is involved in signal transmission from mPR3 during this process. Indeed, neutralizing antibodies against PAR2 inhibited phagocytosis and S. sanguinis-induced calcium mobilization desensitized PAR2. Furthermore, the phagocytosis of S. sanguinis and the concomitant activation of Rho family GTPases were inhibited by the intracellular calcium chelator, BAPTA-AM. Collectively, mPR3 acts as a non-opsonic phagocytosis receptor for bacteria probably by activating PAR2 in neutrophils.
    Molecular Immunology 06/2011; 48(15-16):1966-74. · 2.65 Impact Factor
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    Analytical Biochemistry 03/2010; 398(2):278. · 2.58 Impact Factor
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    ABSTRACT: An easy preparation method of multilayer fluorescence optically encoded beads for protein detection is presented. The beads, which consist of multicolored layers, are made from amino polyethylene glycol grafted polystyrene (PS-g-PEG) beads by using several fluorescent dyes such as fluorescein isothiocyanate (FITC) and rhodamine via controlling diffusion of an Fmoc-protecting group after HCl solution swelling. A biotin, glutathione S-transferase (GST) antibody, and an RNA aptamer that specifically recognize streptavidin, GST antigen, and hepatitis C virus (HCV) helicase are introduced to the optically encoded beads and monitored for their binding activity to the target molecules. After binding, the ligands are identified easily by their color codes.
    Analytical Biochemistry 09/2009; 396(2):313-5. · 2.58 Impact Factor
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    ABSTRACT: This article presents a prototype of a surface-enhanced Raman spectroscopy (SERS)-encoded magnetic bead of 8mum diameter. The core part of the bead is composed of a magnetic nanoparticle (NP)-embedded sulfonated polystyrene bead. The outer part of the bead is embedded with Ag NPs on which labeling molecules generating specific SERS bands are adsorbed. A silica shell is fabricated for further bioconjugation and protection of SERS signaling. Benzenethiol, 4-mercaptotoluene, 2-naphthalenethiol, and 4-aminothiophenol are used as labeling molecules. The magnetic SERS beads are used as substrates for protein sensing and screening with easy handling. As a model application, streptavidin-bound magnetic SERS beads are used to illustrate selective separation in a flow cytometry system, and the screened beads are spectrally recognized by Raman spectroscopy. The proposed magnetic SERS beads are likely to be used as a versatile solid support for protein sensing and screening in multiple assay technology.
    Analytical Biochemistry 06/2009; 391(1):24-30. · 2.58 Impact Factor
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    ABSTRACT: A novel α-Gal resin was chemo-enzymatically synthesized for the efficient adsorption of anti-α-Gal antibodies in human serum for xenotransplantation. To covalently conjugate a hexanoate linker with lactose and N-acetylglucosamine, both acceptor sugars were acetylated and brominated. Then, α-and β-galactoses were sequentially added to the linker-containing saccharides at their non-reducing ends by using recombinant α-(1,3)-and β-(1,4)-galactosyltransferases from E. coli. Finally, the synthesized α-Gal derivatives were immobilized on HiCore, a core-shell type resin, that was functionalized with amino groups on the shell region, as a packing material on-column. Using this method we were able to demonstrate that the α-Gal HiCore resin had a reduced level of non-specific protein adsorption compared with the commercially available polystyrene supports, TentaGel, and agarose-based supports, when Lectin BS-I was used as the model binding protein. Furthermore, the α-Gal HiCore resin was more efficient at eliminating anti-α-Gal IgGs from the total human IgGs through immunoadsorption than the other two α-Gal resins, α-Gal TentaGel and α-Gal agarose. The α-Gal HiCore resin developed in this study can be utilized in a wide range of applications including ex vivo immunoadsorption and as a quantitative assay of anti-Gal antibody in human sera.
    Biotechnology and Bioprocess Engineering 07/2008; 13(4):445-452. · 1.28 Impact Factor
  • Hyung-Seok Jang, Woo-Jae Chung, Yoon-Sik Lee
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    ABSTRACT: In this study, macroporous polystyrene-supported IBX (MPS-IBX) amides were prepared in two simple steps, and the polymeric reagent was then evaluated for its efficiency in converting a range of alcohols to the corresponding carbonyl compounds in various solvents. The results indicated that the MPS-IBX amides were compatible with a variety of solvents, and had a more efficient oxidation activity toward alkyl alcohols than the gel type polystyrene-supported IBX amides. Finally, the resin that was consumed in the oxidation reaction was regenerated to give a restored loading level of 0.44–0.54mmol/g.
    Tetrahedron Letters 01/2007; 48(21):3731-3734. · 2.40 Impact Factor
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    ABSTRACT: Methyl-3-(3-trimethoxysilylpropyl)imidazolium chloride, (TMSPIM)(Cl - ), was synthesized as a precursor of N-heterocyclic carbene (NHC), which can be coordinated with palladium to give an organosilane-based bidentic NHC-Pd complex. The organosilane-based NHC-Pd complex was immobilized covalently on silica particles (NHC-Pd/silica) and then characterized by field emission/scanning electron microscopy (FE/SEM), transmission elec- tron microscopy (TEM), Fourier transform infrared spectroscopy (FTIRS), and inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The Suzuki reaction was per- formed as a model reaction to examine the catalytic activity of NHC-Pd/silica. NHC-Pd/sil- ica exhibited excellent performance in the Suzuki reaction of various aryl halide derivatives (except for aryl chloride derivatives) with phenylboronic acid under mild conditions (room temperature and short reaction time). Moreover, the catalyst was recycled several times with- out any significant loss of catalytic activity in the Suzuki reaction.
    Pure and Applied Chemistry - PURE APPL CHEM. 01/2007; 79(9):1553-1559.
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    ABSTRACT: This paper reports a physical and chemical surface modification technique to achieve a high tethering efficiency as well as controllability and coordinating bacterial cells. This technique was used to experimentally show multiple spin actuators, using the flagellar motion of AMB-1 bacteria. For physical surface modification, a polydimethylsiloxane (PDMS) pillar array, using a soft-lithography technique, was used. For chemical surface modification, a UV-crosslinked azido benzoic acid (ABA) modified surface was used. A high rate of tethering and adhesion of AMB-1 bacterial cells was achieved on the modified surface, and multiple spin actuation and motoring were observed.
    Sensors and Actuators B-chemical - SENSOR ACTUATOR B-CHEM. 01/2007; 123(1):269-276.
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    ABSTRACT: Lipopolysaccharide (LPS)-binding peptides were enriched by using epoxy beads as a novel support to immobilize LPS for a phage displayed peptide library screening. The sequence of Phe-Ala-Pro-Trp (FAPW) was the most significant consensus motif of 10 selected clones, and Pro-Phe (PF) was the key dipeptide for binding at the apex of the loop to form a characteristic structure of CXXPFXXXC. Moreover, AWLPWAK, one of the highly conserved heptamer peptides, could detect specifically Gram-negative bacteria via a whole cell binding test at 10(6) cells ml(-1).
    Biotechnology Letters 02/2006; 28(2):79-84. · 1.85 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
    ChemInform 01/2006; 37(33).
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    ABSTRACT: Solid phase peptide synthesis method, which was introduced by Merrifield in 1963, has spawned the concept of combinatorial chemistry. In this review, we summarize the present technologies of solid phase peptide synthesis (SPPS) that are related to combinatorial chemistry. The conventional methods of peptide library synthesis on polymer support are parallel synthesis, split and mix synthesis and reagent mixture synthesis. Combining surface chemistry with the recent technology of microelectronic semiconductor fabrication system, the peptide microarray synthesis methods on a planar solid support are developed, which leads to spatially addressable peptide library. There are two kinds of peptide microarray synthesis methodologies: pre-synthesized peptide immobilization onto a glass or membrane substrate and in situ peptide synthesis by a photolithography or the SPOT method. This review also discusses the application of peptide libraries for high-throughput bioassays, for example, peptide ligand screening for antibody or cell signaling, enzyme substrate and inhibitor screening as well as other applications.
    Journal of biochemistry and molecular biology 10/2005; 38(5):517-25. · 2.02 Impact Factor
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    ABSTRACT: The selection of identical or highly homologous peptides from phage display combinatorial peptide libraries has been unsuccessful in biopanning experiments using microtiter plates. In the present study, by biopanning on LPS-conjugated epoxy beads, we repeatedly enriched clones encoding AWLPWAK and NLQEFLF. These peptides were found to interact with the polysaccharide moiety of LPS, which is highly variable among gram negative bacterial species. In addition, phages encoding these peptides preferentially bound to the LPS of Salmonella family. AWLPWAK-conjugated beads absorbed Salmonella enteritidis from solution and showed a preference for S. enteritidis over Escherichia coli. In summary, this study shows for the first time that a peptide screened from phage displays of combinatorial peptide libraries can be synthesized on beads and be used practically to concentrate bacterial cells from solution.
    Biochemical and Biophysical Research Communications 05/2005; 329(1):312-7. · 2.41 Impact Factor
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    ABSTRACT: A bead affinity chromatography system, which was based on the photolytic elution method, was integrated into a glass-silicon microchip to purify specific target proteins. CutiCore beads, which were coupled with a photo-cleavable ligand, such as biotin and an RNA aptamer, were introduced into a filter chamber in the microchip. The protein mixture containing target protein labeled with fluorescein isothiocyanate (FITC) was then passed through the packed affinity beads in the microchamber by pressure-driven flow. During the process, the adsorbed protein on the bead was monitored by fluorescence. The concentrated target protein on the affinity bead was released by simple irradiation with UV light at a wavelength of 360 nm, and subsequently eluted with the phosphate buffer flow. The eluted target protein was quantitatively detected via the fluorescence intensity measurements at the downstream of the capillary connected to the outlet of the microchip. The microaffinity purification allowed for a successful method for the identification of specific target proteins from a protein mixture. In addition, the feasibility of this system for use as a diagnosis chip was demonstrated.
    Electrophoresis 03/2005; 26(3):694-702. · 3.26 Impact Factor
  • Woo-Jae Chung, Duk-Ki Kim, Yoon-Sik Lee
    Synlett 01/2005; · 2.66 Impact Factor
  • Duk-Ki Kim, Woo-Jae Chung, Yoon-Sik Lee
    Synlett 01/2005; · 2.66 Impact Factor
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    ABSTRACT: A microbead-based affinity chromatography chip (micro-BACC) controlling hundreds of nanoliters of reaction volume was developed to separate and analyze hepatitis C virus (HCV) RNA polymerase protein by immobilization of an RNA aptamer on beads. A photocleavable linker was conjugated in between the beads and the aptamer to elute the bound RNA polymerase from the RNA aptamer in one step by UV irradiation, resulting in an efficient method to elute and identify the target molecule bound on RNA using a mass spectrometer. This linker showed a cleavage activity over 70% upon UV irradiation at 1050 mW/cm2 for more than 5 min. The photoelution method could prevent the target molecule from contaminations in affinity chromatography caused by elution solutions of high salt concentration, extreme pH and detergent, respectively. In this chip, sample reagents up to 800 nL could be metered quantitatively into the bead chamber using a nanoliter dispenser working, based on surface-guided flow control and pneumatic control by external air pressure on the chip. RNA polymerase eluted after UV irradiation was successfully analyzed by trypsin treatment without additional purification. As a result, using the aptamer, we could detect RNA polymerase from 800 nL hepatitis C patient serum containing 96 fmol HCV RNA polymerase. The detection limit of this system was estimated to be 9.6 fmol HCV RNA polymerase.
    Electrophoresis 12/2004; 25(21-22):3730-9. · 3.26 Impact Factor
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    ABSTRACT: [reaction: see text] Novel core-shell-type resins with a rigid core and amino-functionalized flexible shell were prepared with 2,4,6-trichloro-1,3,5-triazine (CNC) and Jeffamine ED-600 starting from 1% cross-linked aminomethyl (AM) polystyrene resins. All of the amino groups were located outside the resin beads, and the loading capacity was 0.2-0.4 mmol/g. The amount of CNC treated was a determining factor in the properties of the final resins. The core-shell-type resins showed superior performances in terms of the initial loading of amino acid and the photocleavage reaction compared to the gel-type resins.
    Organic Letters 10/2004; 6(19):3273-6. · 6.14 Impact Factor
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    ABSTRACT: We prepared surface-grafted polystyrene (PS) beads with comb-like poly(ethylene glycol) (PEG) chains. To accomplish this, conventional gel-type PS beads (35-75 microm) were treated with ozone gas to introduce hydroperoxide groups onto the surface. Using these hydroperoxide groups, poly(methyl methacrylate) (PMMA, Mn= 22,000-25,000) was grafted onto the surface of the PS beads. The ester groups of the grafted PMMA were reduced to hydroxyl groups with lithium aluminum hydride (LAH). After adding ethylene oxide (EO) to the hydroxyl groups, we obtained the PS-sg-PEG beads, which had a rugged surface and a diameter of 80-150 microm. We could obtain several kinds of the PS-sg-PEG beads by controlling the chain lengths of the grafted PMMA and the molecular weights of the PEG chains. The grafted PEG layer was about 30-50 microm thick, which was verified from the cross-sectioned views of the fluorescamine-labeled beads. These fluorescence images proved that the beads possessed a pellicular structure. Furthermore, we found that the surface-grafted PEG chains had the characteristic property of reducing non-specific protein adsorption on the beads.
    Macromolecular Bioscience 06/2004; 4(5):512-9. · 3.74 Impact Factor
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    ABSTRACT: Glass surfaces were modified using several hydrophilic polymers for the fabrication of protein chips and biosensors. Surface activation was carried out by silanization, and polymer films were introduced to the glass substrates by using two methods. First, preformed amino group containing polymers, capable of reacting with appropriate surface sites, were coupled to the glass substrates. Second, polymer layers were formed by free radical chain polymerization using immobilized initiators. Covalent binding and non-specific antibody adsorption were examined by quantifying IgG-peroxidase conjugates immobilized to the polymer-grafted glass substrates. Polymer-grafted glass substrates showed that non-specific adsorption was reduced by 10–60% as compared with 3-aminopropyltriethoxysilane (APTS)-treated substrate. In particular, chitosan-grafted substrates exhibited very low non-specific protein adsorption. Despite this protein-rejecting phenomenon of the surface-bound polymer, the quantity of antibodies immobilized by covalent binding to the polymer-grafted glass substrates was comparable to that immobilized on the non-polymer-grafted surface. We also performed a protein patterning experiment on the polymer-grafted surface by using maskless photolithography. We found that the chitosan-grafted glass substrate, with good protein repellency, displayed a very clear streptavidin-patterned surface.
    Colloids and surfaces B: Biointerfaces 01/2004; 33(2):67-75. · 3.55 Impact Factor

Publication Stats

169 Citations
53.45 Total Impact Points

Institutions

  • 2014
    • Sungkyunkwan University
      • Department of Genetic Engineering
      Sŏul, Seoul, South Korea
  • 2002–2010
    • Seoul National University
      • • Department of Chemical and Biological Engineering
      • • School of Chemical and Biological Engineering
      • • School of Computer Science and Engineering
      Sŏul, Seoul, South Korea
  • 2006
    • University of Seoul
      • Department of Chemical Engineering
      Sŏul, Seoul, South Korea