» Research Group web page (updated on 08.12.2008)		Yan-Yeung Luk  Assistant Professor Bioorganic chemistry; surfaces; nanomaterials; chemical biology yluk@syr.edu phone: 315-443-7440 / fax: 315-443-4070 Office: CST 3-048 Education: • B.S., 1994, Polytechnic University • Ph.D., 2001, University of Chicago • Postdoctoral Fellow, University of Wisconsin-Madison Courses: • CHE 117: General Chemistry Laboratory • CHE 400/600: Chemistry at the Interfaces – Biomaterials • CHE 427/627*: Intermediate Organic Chemistry   * denotes current Fall '08 course

Research Interests      Our research explores significant interfaces adjoining chemistry and biology. The four examples of such interfaces below are intertwined with each other. Principles for amphiphile-free water-in-water emulsions: templated synthesis and biocatalysis. Chemoselective organic reactions in water, and their applications. Surfaces for controlling mammalian cell adhesion and biofilm formation. Unique structures formed from multi-conformational compounds through specific folding preferences. Intermolecular self-assembly in water often involves hydrophobic/hydrophilic interactions. In area 1, we study a fundamentally new amphiphile-free water-in-water (w/w) emulsion system that consists of polymer-coated water droplets, which are also stably dispersed in water. The droplets contain a non-amphiphilic liquid crystal (disodium cromolycate) solvated and ordered in water. This work will reveal how molecular interactions, not involving hydrophobic-hydrophilic interactions, of designed organic molecules in water can give rise to novel assemblies and materials structures at nanometer and micrometer-scale. Using this new colloidal science, we have developed a one-pot synthesis to produce porous hydrogels with novel microstructures, and with spatially localized protein immobilization. Significant enhancement of enzymatic activity from protein immobilized on this porous hydrogel is observed over non-porous hydrogel. The enhancement far exceeds the contribution from increased diffusion of the reactants due to the porosity of the materials. Study of the mechanisms for the formation of this w/w emulsion, which include thermodynamic incompatibility of non-amphiphilic molecules and multivalent binding at the interface, has led to a genesis of new materials including, connected hydroshells, biocontinuous organic structure and elongated micrometer core-shells with a gradient in the density of the materials, and has shown potential for a wide range of applications.      In area 2, chemoselective organic reaction in water, we have made a discovery of a water-driven chemoselective reaction in an entirely aqueous environment. The squarate molecule used in this reaction can distinguish the more reactive cysteines as a function of thiol acidity due to the different positions in a peptide or a protein. This reaction is used to immobilize proteins on self-assembled monolayers for study of mammalian cell biology and biofilm biology (see area 3). This class of organic reactions also leads to the efficient synthesis (2-4 steps) of a new class of highly active non-peptide integrin antagonists.      In area 3, biosurfaces, we use surfaces prepared with control of both surface chemistry and topography at the nanometer-scale to enhance mammalian cell adhesion and confinement. We demonstrated that confinement of mammalian cell adhesion by the bioinert chemistry on surfaces can be enhanced significantly by increasing the surface anisotropy at nanometer-scale. We also designed bio-inert surfaces able to confine biofilms in patterned areas for an unprecedented period of time. We also designed an efficient one-step synthesis for highly active brominated furanones that inhibit the formation of biofilms. Using a surface with a chemical gradient of bioinertness, we have identified that biofilm formation does not appear to require a specific molecular recognition event for the initial attachment.      In area 4, molecular folding with abiotic structural motifs, we develop principles and understanding of molecular folding using structural motifs that are not of biological origins. We have synthesized a novel surfactant that folds into a unique structure, which further assemble to form novel aggregate structures in water. These aggregate structures do not denature membrane proteins. We also explore using stereogenic protons on non-planar aromatic moiety to guide molecular folding. We demonstrated a resolved that diastereomers with a C3 dissymmetric core folds into two grossly different structures with chiral cavities. We will use this class of molecules as scaffold to reconstruct the active sites of enzymes or antibodies by organic synthesis. Selected Publications Utilizing the high dielectric constant of water: efficient synthesis of amino acid-derivatized cyclobutenones Jun Li, Yongbin Han, Teresa B. Freedman, Shifa Zhu, Deborah J. Kerwood and Yan-Yeung Luk*, Tet. Lett., 2008, 49(13), 2128-2131. » full article Chiral Molecules with Polyhedral T, O or I Symmetry: Theoretical Solution to A Difficult Problem in Stereochemistry Sri Kamesh Narasimhan, Xiaoying Lu and Yan-Yeung Luk* Chirality 2008, 20(8) 878-884. » full article Identifying the important structural elements of brominated furanones for inhibiting biofilm formation by Escherichia coli Yongbin Han, Shuyu Hou, Karen A. Simon, Dacheng Ren* and Yan-Yeung Luk*, Bioorg. Med. Chem. Lett., 2008, 18(3), 1006-1010. » full article Water-Driven Chemoselective Reaction of Squarate Derivatives with Amino Acids and Peptides Preeti Sejwal, Yongbin Han, Akshay Shah and Yan-Yeung Luk*, Org. Lett., 2007, 9, 4897-4900. » full article Enhancing Cell Adhesion and Confinement by Gradient Nanotopography Karen A. Simon, Erik A. Burton, Yongbin Han, Jun Li, Anny Huang and Yan-Yeung Luk*, J. Am. Chem. Soc., 2007, 129, 4892-4893. » full article Water-in-Water Emulsions Stabilized by Non-Amphiphilic Interactions: Polymer-Dispersed Lyotropic Liquid Crystals Karen A. Simon, Preeti Sejwal, Ryan B. Gerecht, Yan-Yeung Luk*, Langmuir, 2007, 23, 1453-8. » full article A Biocompatible Surfactant with Folded Hydrophilic Head Group: Enhancing the Stability of Self-Inclusion Complexes of Ferrocenyl in a β-Cyclodextrin Unit by Bond Rigidity Yongbin Han, Kejun Cheng, Karen A. Simon, Yanmei Lan, Preeti Sejwal, Yan-Yeung Luk*, J. Am. Chem. Soc., 2006, 128, 13913-20. » full article Inhibiting Escherichia Coli Biofilm Formation by Self-Assembled Monolayers of Functional Alkanethiols on Gold Shuyu Hou, Erik A. Burton, Karen A. Simon, Dustin Blodgett, Yan-Yeung Luk* and Dacheng Ren*, Appl. Environ. Microbiol. 2007, 73, 4300-4307. » full article Surface-Driven Switching of Liquid Crystals using Redox-Active Groups on Electrodes Yan-Yeung Luk, Nicholas L. Abbott,* Science, 2003, 301, 623-6. » View all Publications