Suk-Wah Tam-Chang

Professor

Organic and Materials Chemistry; Biosensors

B.S. (1983), University of Hong Kong; Ph.D. (1992), University of California at Los Angeles (F. N. Diederich); Postdoctoral (1992-1993), NIH postdoctoral fellow (1994) Harvard University (G. M. Whitesides).

E-mail: tchang [at] unr.edu
Phone: 775-784-6661
FAX: 775-784-6804
Office: CB 326

Suk-Wah Tam-Chang

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Research Interests

Design and Synthesis of Organic Compounds that are Useful as Dichroic Dyes, Fluorophores, Near Infrared Dyes, and Chromonic Liquid-Crystals

An important goal of our research is to increase our basic knowledge of the relationships between molecular structure, supramolecular interactions, phase behavior, molecular orientation, and physical properties of organic compounds in the liquid-crystalline state and in the solid state. We are particularly interested in the synthesis and studies of liquid-crystalline compounds that exhibit dichroic properties (direction-dependent absorption of light) and fluorescence emission at long wavelengths. Dichroic dyes and fluorophores can potentially be used as sensing probes in biological studies and as polarizing materials in liquid-crystal displays (LCDs). In addition, long wavelength absorbing materials can potentially be used in optical applications in conjunction with commercially available AlGaAs lasers that emit at 780 nm. Near-infrared (NIR) absorbing and emitting dyes have potential use in high-technology applications such as optical recording, thermally-written displays, laser printers, laser filters, infrared photography, and fiber-optic communications.

Micro- and Nanofabrication of Anisotropic Organic Materials via Template-Guided Organization of Organic Compounds

Micro- and nano-patterned organic semiconducting materials have potential applications in the field of microelectronics, where the direction-dependent orientation of the molecules in these materials can enhance their semiconducting properties. In addition, patterned anisotropic (direction-dependent) materials have potential applications as angle-dependent optical materials, holographic films, and in stereoscopic displays. These organic materials may also have useful photonic and optoelectronic properties. A wide range of methods is available for the micro- and nano-patterning of isotropic (direction-independent) materials including scanning probe techniques, electron-beam lithography, photolithography, and soft-lithography. However, techniques for the micro-fabrication of anisotropic organic materials is presently limited to approaches that employ either uniaxially stretched polymer films or photo-alignment techniques. Our research group is interested in the micro- and nano-fabrication of anisotropic organic materials by template-guided organization of chromonic liquid crystals.

Biosensors

Biosensors are devices interfaced with biological detector molecules for identifying specific target analytes. Biosensors have applications that range from medical diagnostics to environmental analysis, Our current interest focuses on the research and development of biosensors for detecting unlabeled nucleic acids.

Instrumentation and Techniques involved

  • Techniques for the synthesis of organic compounds
  • Fluorescence and radioactive labeling of biological molecules
  • Reactions and techniques for immobilizing organic and biological molecules on surfaces
  • High pressure liquid-chromatography
  • Radioactivity counting and imaging
  • NMR spectroscopy
  • UV-vis and polarized uv-vis spectroscopy
  • FTIR and polarized FTIR spectroscopy
  • Fluorescence and polarized fluorescence spectroscopy
  • Optical microscopy and polarized optical microscopy
  • Fluorescence microscopy
  • Confocal microscopy
  • Atomic force microscopy
  • Scanning electron microscopy
  • Electrochemistry
  • X-ray diffractometry (single crystal and small angle)

Selected Publications

“Microfabrication of anisotropic organic materials via self-organization of an ionic perylenemonoimide,” Huang, L.; Tam-Chang, S.-W.; Seo, W.; Rove, K. Adv. Mater. 2007 [Communication] (Accepted).

“Stem-loop probe with universal reporter for sensing unlabeled nucleic acids,” Tam-Chang, S.-W.; Carson, T.D.; Huang, L.; Publicover, N.G.; Hunter, K.W., Jr. Anal. Biochem. 2007, 326, 126-130.

“Anisotropic fluorescent materials via self-organization of perylenedicarboximide,” Huang, L.; Catalano, V.J.; Tam-Chang, S.-W. Chem. Commun. 2007, 2016-2018. [Communication]

“Template-guided organization of chromonic liquid crystals into micropatterned anisotropic organic solids,” Tam-Chang, S.-W.; Helbley, J.; Carson, T.D.; Seo, W.; Iverson, I.K. Chem. Commun. 2006, 503-505. [Communication]

“Materials and methods for the preparation of anisotropically-ordered solids,” Carson, T.D.; Casey, S.M.; Iverson, I.K.; Seo, W.; Tam-Chang, S.-W. Patent # WO2005089094, published 9/29/05.

“Methods and arrays for detecting and quantitating nucleic acids,” Tam-Chang, S.-W.; Hunter, K.W.; Publicover, N.G. Patent # WO2005047468, published 5/26/05.

“Molecularly designed chromonic liquid crystals for the fabrication of broad spectrum polarizing materials,” Tam-Chang, S.-W.; Seo, W.; Rove, K.; Casey, S.M. Chem. Mater. 2004, 16, 1832-1834. [Communication]

“Synthesis and studies of the properties of a liquid crystalline quaterrylenebis(dicarboximide) by 1H NMR and UV-vis spectroscopies,” Tam-Chang, S.-W.; Seo, W.; Iverson, I.K. J. Org. Chem. 2004, 69, 2719-2726.

“Study of the chromonic liquid-crystalline phases of bis-(N,N-diethylaminoethyl)perylene-3,4,9,10-tetracarboxylic diimide dihydrochloride by polarized optical microscopy and 2H NMR spectroscopy,” Tam-Chang, S.-W.; Iverson, I.K.; Helbley, J. Langmuir 2004, 20, 342-347.

“Novel polarized photoluminescent films derived from sequential self-organization, induced-orientation, and order-transfer processes,” Carson, T.D.; Seo, W.; Tam-Chang, S.-W.; Casey, S.M. Chem. Mater. 2003, 15, 2292-2294.

“Ionic Quaterrylenebis(dicarboximide): A Novel Mesogen and Long-Wavelength Polarizing Material,” Tam-Chang, S.-W.; Seo, W.; Iverson, I.K.; Casey, S.M. Angew. Chem. Int. Ed. 2003, 42, 897-900.

“Synthesis of cetyl myristoleate and evaluation of its therapeutic efficacy in a murine model of collagen-induced arthritis,” Hunter, K.W., Jr.; Gault, R.A.; Stehouwer, J.S.; Tam-Chang, S.-W. Pharmacol. Res. 2003, 47, 43-47.

“Controlling molecular orientation in solid films via self-organization in the liquid-crystalline phase,” Iverson, I.K.; Casey, S.M.; Seo, W.; Tam-Chang, S.-W.; Pindzola, B.A. Langmuir 2002, 18, 3510-3516.

“Modulating the redox property of a flavin analog through adjustment of its microenvironment in a self-assembled monolayer,” Carson, T.D.; Tam-Chang, S.-W.; Beck, H.E. Antioxidants and Redox Signaling 2001, 3, 731-736.

“Synthesis of symmetrical and unsymmetrical alkyl disulfides with attached flavin analog for formation of self-assembled monolayers on gold,” Tam-Chang, S.-W.; Mason, J. Tetrahedron 1999, 55, 13333-13344.

“Cascade of molecular order through sequential self-organization, induced orientation, and order transfer processes,” Iverson, I.; Tam-Chang, S.-W. J. Am. Chem. Soc. 1999, 121, 5801-5802.

“Formation of a macrobicyclic tris(disulfide) by molecular self-assembly,” Tam-Chang, S.-W.; Stehouwer, J.S.; Hao, J. J. Org. Chem. 1999, 64, 334-335.

“Modulating the pH-dependent redox potential of a flavin analog via incorporation into self-assembled monolayer on gold,” Tam-Chang, S.-W.; Mason, J.; Iverson, I.; Hwang, K.-O.; Leonard, C. Chem. Commun. 1999, 65-66.

“Novel dichroic polarizing materials and approaches to large area processing,” Bobrov, Y.A.; Casey, S.M.; Ignatov, L.Y.; Lazarev, P.; Phillips, D.; Tam-Chang, S.-W. Mater. Res. Soc. Proc. 1998, 508, 225-228.

“Applications of self-assembled monolayers of alkanethiolates on gold,” Tam-Chang, S.-W.; Iverson, I., in Adsorption and its Applications in Industry and Environmental Protection Dabrowski, A., Ed., Elsevier, 1998, pp. 917-957.