UMD Scientists and Engineers Present Papers at American Chemical Society Meeting

Sunday

60 - Preparation of glycomic microarrays using catanionic surfactant vesicles: Applications in diagnostics

Neeraja J Dashaputre¹, neerajad@umd.edu, Philip DeShong¹, Srinivasa R Raghavan², Gregory F Payne³. (1) Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, U.S., (2) Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, MD 20742, U.S., (3) Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, MD 20742, U.S.

Formation of glycomic microarrays has been accomplished by deposition of catanionic surfactant vesicles on hydrophobically-modified chitosan (HMc) surfaces. The vesicles remain intact after deposition on the HMc surface. Vesicles that were functionalized with glycoconjugates (glucose, lactose) were deposited on the HM chitosan surface to prepare glycomic microarrays. Lectin binding studies show that the carbohydrates on the vesicle surface are available for binding. Concanavalin A (Con A) binding to vesicles functionalized with glucose, and peanut agglutinin (PNA) binding to vesicles functionalized with lactose were studied and observed to be selective to respective binding components. Vesicles functionalized with lipoligosaccharide (LOS) of Neisseria gonorrhoeae and vesicles incorporated with extracted cell membrane of Neisseria gonorrhoeae showed binding with a monoclonal antibody specific for the LOS. Another approach towards making carbohydrate microarrays by inkjet printing the vesicles is discussed. Inkjet printing techniques can be utilized for the production of complex glycomic microarrays.
Sunday, April 7, 2013 09:00 AM
Materials, Devices and Switches (08:00 AM - 11:20 AM)
Location: Morial Convention Center
Room: 242

55 - RNA folding in crowded solutions
Sarah A Woodson¹, swoodson@jhu.edu, Duncan Kilburn¹, Reza Behrouzi¹, Robert M. Briber², Joon Ho Roh². (1) Biophysics, Johns Hopkins University, Baltimore, MD 21218, U.S., (2) Materials Science and Engineering, University of Maryland, College Park, MD 20742, U.S.

Many non-coding RNAs must fold into specific three-dimensional structures. In the cell, the stability of the folded RNA depends on its interactions with ions and with other solutes that take up 30% of the available volume. Using small angle X-ray scattering to measure the folding of a bacterial group I ribozyme, we find that molecular crowding equivalent to what is present in real cells stabilizes RNA tertiary structures by several kcal/mol. Systematic perturbations to scattering functions and experiments at different temperatures show this stabilization is partly due to reduced conformational entropy of the unfolded RNA. Compression of the native state ensemble in crowded solutions correlates with an increase in ribozyme catalytic activity. Consequently, the ribozyme reaches its catalytically active structure at much lower Mg²⁺ concentrations in a crowded milieu than in a dilute solution.

Sunday, April 7, 2013 04:05 PM
Frontiers in RNA Catalysis and Folding: Interface of Theory and Experiment (01:30 PM - 05:05 PM)
Location: Astor Crowne Plaza - New Orleans
Room: Grand Ballroom A

451 - AAO as a 1D template for geometric confinement of liquid crystals

Sunhee Lee¹, lsh7286@gmail.com, Hanim Kim¹, Eva Korblova², David M Walba², Dong Ki Yoon¹, Sang Bok Lee^1,3. (1) Graduate School of Nanoscience and Technology, KAIST, Daejeon, Republic of Korea, (2) Department of Physics and Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, U.S., (3) Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, U.S.

Anodic aluminum oxide (AAO) membrane composed of hexagonal, closely packed nanochannel arrays has gained significant attention due to its structural potential as a template material for metal/metal oxide nanowires, energy storage, catalysts and sensor system. We describe the spatial confinement effect of liquid crystal loaded in surface modified AAO. Orientation of liquid crystal molecules in surface modified AAO affected by surface tension and surface energy so helical nanofilament and nanodisk can be spontaneously assembled depending on surface properties with same materials. Electron microscope cross section images of the liquid crystals in surface modified nanochannel revealed the tendency and correlation between the surface energy and the geometrical conformation of liquid crystals. GIXD (Grazing incidence x-ray diffraction) analysis also shows the details of molecule orientation and layer align direction. Our approaches will be helpful for fundamental studies and applications which describe the liquid crystal confinement effects on surface treatment in AAO confinement system.
Sunday, April 7, 2013 06:00 PM
Nanoscience (06:00 PM - 08:00 PM)
Location: Morial Convention Center
Room: Hall D

Monday

105 - From fibrous biological tissues to adaptable hydrogel materials

Ziliang Wu¹, Heloise Therien-Aubin¹, Michael Moshe³, Jesse Greener¹, Zhihong Nie², Eran Sharon³, Eugenia Kumacheva¹, ekumache@chem.utoronto.ca. (1) Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada, (2) Department of Chemistry and Biochemistry, University of Maryland, College Park, U.S., (3) The Racah Institute of Physics, Hebrew University, Jerusalem, Israel

Plants possess a unique ability to change their shape in response to the changes in ambient conditions. These transitions are believed to be governed by the non-uniform accumulation of elastic energy and the release of localized stresses. The self-shaping behaviour of plants offers a new paradigm for creating adaptable materials by-design, however currently prediction of 3D transformations in soft matter remain a challenge. Being inspired by the remarkable structure-property relations in fibrous tissues of plants, we developed a nature-inspired strategy for the generation of complex 3D structures by programming stimuli-responsive deformations of composite hydrogels. We used a combination of different materials and stimuli to predict and program well-defined shape transformations of the planar hydrogel sheets. This work constitutes a major step toward the design of adaptable soft materials with applications in sensing, actuation and locomotion.
Monday, April 8, 2013 11:00 AM
ACS Award in Applied Polymer Science: Symposium in Honor of Mitchell A. Winnik (08:55 AM - 12:00 PM)
Location: Hilton Riverside
Room: HEC A

400 - Molecular ordering in PCBM monolayer films on Ag and Au (111): From m-aerosol deposited glasses to hcp packing

Qian Shao, qshao@umd.edu, Levan Tskipuri, Janice Reutt-Robey. Chemistry & Biochemistry, University of Maryland-College Park, College Park, MD 20742-2111, U.S.

Functionalized C₆₀ and C₇₀ fullerenes are increasingly employed as active components in organic electronic devices. The structure of the PCBM electrode interface is expected to strongly impact charge transfer processes in photovoltaic devices. Here we report molecularly-detailed studies of PCBM ordering at coinage metal surfaces. We have developed a vacuum-compatible liquid delivery source to generate thin films of C₆₀- and C₇₀-PCBM from organic solvents. Structure is tracked from the sub-monolayer to multilayer regime on (111)-oriented Ag and Au surfaces with molecular detail by UHV-STM. Glassy morphologies of as-grown films reflect solvent retention. Upon thermal annealing solvent molecules are released and films evolve into ordered packing arrangements that depend upon the PCBM density in the original films. The hcp monolayer phase of C₆₀-and C₇₀-PCBM are newly produced and characterized, indicating the accessibility of new growth phases by m-aerosol deposition. Acknowledgement: This work was supported by the NSF-MRSEC at the University of Maryland, DMR 0520471.
Monday, April 8, 2013 06:00 PM
Fundamental Research in Colloid and Surface Science (06:00 PM - 08:00 PM)
Location: Morial Convention Center
Room: Hall A, Sec D

Tuesday

476 - Hydrophobically modified biopolymer as enhanced carrier for in situ groundwater remediation

Rubo Zheng¹, rzheng@tulane.edu, Jingjing Zhan¹, Srinivasa R Raghavan², Bhanukiran Sunkara¹, Vijay T John¹. (1) Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, U.S., (2) Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, U.S.

Carbon submicrospheres as a carrier for nanoscale zerovalent iron particles are of much potential in the remediation of chlorinated compounds. Effective in situ groundwater remediation requires the successful delivery of these reactive systems through soil without aggregation. Here, we show that hydrophobically modified chitosan(HMC), with C12 alkyl groups stabilize carbon submicrospheres through hydropobic interactions. Detailed NMR characterizations indicate attachment of the alkyl groups onto the microspheres. The coating of the environmentally benign biopolymer therefore leads to suspension stability of these submicrospheres through electrostatic and steric repulsion. Compared with pristine chitosan and commonly used sodium carboxymethyl cellulose (CMC), HMC is more effective in stabilizing carbon submicrospheres, and this is even enhanced under normal groundwater iron strength condition. Our results indicate that this system has optimal transport characteristics in groundwater saturated sediments with carbon submicrospheres attachment efficiency of 0.04 calculated from breakthrough data of capillary transport experiments. The fundamental concepts will be detailed in the talk.
Tuesday, April 9, 2013 11:15 AM
Chemical Pictures of Environmental Interfaces: Advances in Molecular-Level Understanding and Quantitative Analysis of Species (08:30 AM - 11:35 AM)
Location: New Orleans Marriott
Room: Studio 3

184 - Designing a new generation of polymeric hemostats that can rapidly stop bleeding from serious wounds

Srinivasa R. Raghavan, sraghava@umd.edu, Matthew B. Dowling. Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, U.S.

When we suffer a wound, our body initiates the clotting cascade at the wound site, which ultimately results in a clot, i.e., a protein gel, that immobilizes blood cells and thereby achieves hemostasis. Gelation of blood is thus critical to hemostasis, and the need for an effective hemostat is particularly important in the case of soldiers on the battlefield. Here, we demonstrate the ability to gel blood using a self-assembling biopolymer. The biopolymer is a hydrophobically modified (hm) derivative of the polysaccharide, chitosan. When hm-chitosan is contacted with heparinized human blood, it rapidly transforms the liquid into an elastic gel. In contrast, the native chitosan (without hydrophobes) does not gel blood. Gelation occurs because the hydrophobes on hm-chitosan insert into the membranes of blood cells and thereby connect the cells into a sample-spanning three-dimensional network. We are currently evaluating hm-chitosan as an effective, yet low-cost hemostat for use by trauma centers and the military. Several embodiments of hm-chitosan have been tested, including solutions, bandages, and foams. Preliminary tests with small and large animal injury models show the efficacy of these hm-chitosan-based systems at achieving rapid hemostasis, even for severe life-threatening injuries. [Reference: Dowling et al., Biomaterials, 32, 3351 (2011).]
Tuesday, April 9, 2013 11:25 AM
Biomaterials and Biomedical Engineering (08:30 AM - 12:25 PM)
Location: Hilton Riverside
Room: Grand Salon D22

530 - Ultrathin coating of Al₂O₃ on negative electrode for lithium ion batteries

Minho Yang¹, minho.yang@kaist.ac.kr, Sang Bok Lee^1,2. (1) graduate school of nanoscience and technology, Korea Advenced Institute of Science and Technologe, Yuseong-gu, Daejeon 305-701, Republic of Korea, (2) Department of Chemistry and Biochemistry, University of Maryland, College park, Maryland 20742, U.S.
Next generation lithium ion batteries have required the high energy/power density and long cycling stability for powering transportation and grid systems. The silicon has been expected as a suitable negative electrode to apply these areas due to high theoretical energy capacity (4200 mAh/g). However, the silicon suffers from huge volume expansion, which cause loss of electrical contact among active materials and finally capacity fading. Here, we demonstrated the ultrathin coating of Al₂O₃ on patterned silicon wafer (p-Si) as a negative electrode for lithium ion batteries by surface sol-gel method. Al₂O₃ coated p-Si was characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The TEM and XPS data revealed that the p-Si was conformably coated with 5 nm of Al₂O₃. The electrochemical behavior and cycle performance were examined by cyclic voltammetry, electrochemical impedance spectroscopy, and battery cycler.

Tuesday, April 9, 2013 02:00 PM
Advances in Energy and Fuels Processes, Systems, Materials and Utilization (02:00 PM - 04:00 PM)
Location: Morial Convention Center
Room: Hall D

491 - Synthesis of Au-Pd bimetallic nanocrystals with high-index-faceted nanocrystals and study of their electrochemical property

Dongheun Kim¹, dongheun@kaist.ac.kr, Sang Woo Han², Sang Bok Lee^1,3. (1) Graduate school of nanoscience and technology, KAIST, Daejeon, Republic of Korea, (2) Department of chemistry, KAIST, Daejeon, Republic of Korea, (3) Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, U.S.

The shape-controlled synthesis of metal nanocrystals (NCs) has received increasing attention in recent years because NC shape has a profound influence on the optical, magnetic, and catalytic properties of NCs. In particular, the catalytic activities and stabilities of NCs in numerous chemical reactions significantly depend on NC shape. This could be due to specific combinations of the facet types on the NC surface and the overall shape of the NC. In recent years, the synthesis of high-index-faceted NCs has attracted a great deal of attention. High-index facets consist of surface atoms with relatively lower coordination numbers than those of low-index facets due to the presence of high-density atomic steps and kinks on them. Despite the fact that bimetallic NCs have higher catalytic performance than their monometallic counterparts and that their properties can be tuned by tailoring their morphologies, the synthesis of high-index-faceted bimetallic NCs has been relatively unexplored compared to monometallic NCs. Herein, the synthesis of high-index-faceted bi-metallic NCs with unprecedented morphologies and their unique catalytic properties are reported.
Tuesday, April 9, 2013 04:55 PM
Fuel Cell Science and Technologies (01:00 PM - 05:15 PM)
Location: Morial Convention Center
Room: 231

805 - Synthesis of hexoctahedral Au-Pd alloy nanocrystals and study of their electrochemical property

Dongheun Kim¹, dongheun@kaist.ac.kr, Sang Woo Han², Sang Bok Lee^1,3. (1) Graduate School of Nanoscience and Technology, KAIST, Daejeon, Republic of Korea, (2) Depotment of chemistry, KAIST, Daejeon, Republic of Korea, (3) Department of chemistry and Biochemistry, University of Maryland, College Park, MD 20742, U.S.

Hexoctahedral (HOH) Au-Pd alloy NCs bound entirely by high-index {541} facets were prepared through a facile one-pot aqueous synthesis method. This unique structure was produced by the co-reduction of Au and Pd precursors under kinetically controlled nucleation and growth conditions without added seeds or additional structure-regulating metal ions. The synthesized HOH Au-Pd NCs were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis spectroscopy to confirm the shape, composition and structure evolution of NCs. The HOH Au-Pd NCs exhibited higher catalytic performance toward the electro-oxidation of ethanol than Au-Pd NCs bound by low-index facets
Tuesday, April 9, 2013 06:00 PM
Heterobimetallic Compounds and their Chemistry (06:00 PM - 08:00 PM)
Location: Morial Convention Center
Room: Hall D

952 - Quantitative analysis of cationic colloidal silica nanoparticles internalization in human breast cancer cell

Jihyun Soeg¹, januaryt@kaist.ac.kr, Bokyung Kong¹, Dong Heun Kim¹, Sang Bok Lee^1,2. (1) Graduate School of Nanoscience and Technology, KAIST, Daejeon, Republic of Korea, (2) Department of Chemistry and Biochemistry, University of Maryland, College park, MD 20742, U.S.

The cationic colloidal silica nanoparticles method has been widely used for the plasma membrane isolation. This technique that was developed by Chaney and Jacobson has been applied to suspension cell cultures, monolayer cell cultures and tissues for proteomic analysis of plasma membrane and has been shown successful for plasma membrane isolation. However, silica nanoparticles are doubted to be internalized into the cell, because the concentration of silica nanoparticles used for the isolation of plasma membrane proteins is pretty high. Here, we evaluated internalization in human breast cancer cells (MCF-7) .The internalized cationic silica nanoparticles throughout the cell organelles, including the vesicle, cytoplasm, and nuclear membrane were observed with the transmission electron microscopy (TEM) images and energy dispersive spectroscopy (EDS). Moreover, the ratio of silica nanoparticles between cell membrane and intracellular compartment were quantified using inductively coupled plasma atomic emission spectroscopy (ICP-AES).
Tuesday, April 9, 2013 06:00 PM
Nanoscience (06:00 PM - 08:00 PM)
Location: Morial Convention Center
Room: Hall D

Wednesday

528 - From reverse micelles to reverse vesicles: Principles for modulating self-assembly in nonpolar organic solvents

Srinivasa R Raghavan, sraghava@umd.edu, Kevin K Diehn, Hee-Young Lee, Shih-Huang Tung. Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, U.S.

It is well-known that self-assembly of lipids and surfactants in water leads to structures such as micelles and vesiclesin dilute solution. In contrast, however, self-assembly in nonpolar organic solvents (oils) is much less studied. Standard textbooks in colloid science make only a brief mention of reverse micelles, which are typically assumed to be spherical. In the specialized literature, a few systems have been reported in which reverse spherical micelles can be transformed into reverse cylindrical micelles, typically upon addition of a polar substance like water. There is scant discussion of other non-micellar reverse phases such as reverse vesicles.
In our laboratory, we have found that reverse self-assembly is a much richer subject than is known, and it is full of interesting and surprising findings. For example, we have found that simple salts can influence the reverse self-assembly of lipids in oil (salts can be dissolved in oil only in the presence of lipid). Moreover, the nature of the salt cation is found to critically influence reverse self-assembly. For example, in mixtures with the unsaturated phospholipid, soybean lecithin we have found that salts of multivalent cations such as Ca²⁺, Mg ²⁺, La³⁺ and Gd ³⁺induce the formation of reverse cylindrical filaments and in turn their organogels. This behavior is not seen with univalent cations like Na⁺ or K⁺ . Additionally, when combined with a saturated phospholipid, we have found that the same multivalent cations induce the formation of reverse multilamellar vesicles (reverse “onions”). Many of these results on reverse self-assembly can be rationalized based on molecular-geometry (packing parameter) principles, much like in the case of aqueous self-assembly.
Wednesday, April 10, 2013 11:10 AM
One Hundred Years of Micelles: Advances in Molecular Self-Assembly (08:30 AM - 12:00 PM)
Location: New Orleans Marriott
Room: Studio 6

690 - Nano-structured Li-ion battery anode materials via aerosol assisted synthesis

Juchen Guo¹, jguo@engr.ucr.edu, Zichao Yang², Lynden A Archer², Qing Liu³, Michael R Zachariah³, Chunsheng Wang⁴. (1) Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, California 92521, U.S., (2) School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, U.S., (3) Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, U.S., (4) Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, U.S.

The realization of high capacity anode materials including manganese oxide and tin for Li-ion batteries is hindered by their inferior cycle stability due to the drastic volume change and the degradation of the reversible lithiation-delithiation process. To overcome these challenges, rationally designed amorphous MnO_x-C nanocomposite and Sn-C nanocomposites with various structures are synthesized using a robust aerosol spray pyrolysis method. As the result, the amorphous MnO_x-C ans Sn-C nanoparticles demonstrate the best performance as anode materials for Li-ion batteries to date.
Wednesday, April 10, 2013 03:20 PM
Capacitors and Related Systems for Energy Storage (01:30 PM - 04:40 PM)
Location: Morial Convention Center
Room: 226

Thursday

780 - Conductive paper based energy devices for grid-scale storage

Liangbing Hu, binghu@umd.edu, Materials Science and Engineering, University of Maryland College Park, College Park, MD 20742, U.S.

Rational designs and large-scale manufacturing of energy devices are critical for next-generation energy storage devices, especially for GRID scale storage. In this talk, I will review the progress of paper based energy storage devices and discuss our recent development based on conductive paper. Supercapacitors and batteries will be discussed in detail.
Thursday, April 11, 2013 08:35 AM
Capacitors and Related Systems for Energy Storage (08:00 AM - 11:25 AM)
Location: Morial Convention Center
Room: 226

782 - Nanoporous materials for improved performance in electrochemical pseudocapacitors and batteries

Iris Rauda¹, Veronica Augustyn², Chris Kang¹, Xinyi Chen⁴, Raffaella Buonsanti⁵, Delia Milliron⁴, Gary Rubloff⁵, Bruce Dunn², Sarah H Tolbert¹, tolbert@chem.ucla.edu. (1) Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, U.S., (2) Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, U.S., (4) Materials Science and Engineering, University of Maryland, College Park, Maryland, U.S., (5) The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.

Nanoporous materials provide exciting opportunities for improving the performance of electrochemical energy-storage devices such as pseudocapacitors and batteries. By producing materials with controlled porosity and high surface area, systems can be optimized for applications where performance is determined by electrical connectivity, electrolyte access, and surface redox. Here, we first examine porous pseudocapacitors built from nanocrystal building-blocks. The architecture produces fast redox kinetic with a variety of porous metal-oxides materials. Composite systems are also produced that combine efficient electrical conductivity with kinetically accessible redox sites. Moreover, in some materials we find that pore flexibility combined with short diffusion lengths produces a phenomena called intercalation pseudocapacitance, where traditional battery-like intercalation become kinetically facile. For high-capacity anodes, we examine porous silicon produce by reduction of template porous silica. Here, the mechanical flexibility of nanoporous materials can produce robust cycling behavior, despite the large volume increase that occurs in silicon upon alloying with lithium.
Thursday, April 11, 2013 09:40 AM
Capacitors and Related Systems for Energy Storage (08:00 AM - 11:25 AM)
Location: Morial Convention Center
Room: 226

773 - Adsorption energetics and reactions of ethylene carbonate-lithium and reaction pathways on C(0001)

Wentao Song, wtsong@umd.edu, Satyaveda Bharath, Janice Reutt-Robey. Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, U.S.

The decomposition of molecular electrolytes at carbon anode surfaces in Li-ion energy storage devices creates a passivating layer known as the solid electrolyte interphase (SEI). The energetics and molecular events in the formation of the SEI layer are not yet firmly established. To investigate the onset of SEI formation, a Li-HOPG(C(0001))-ethylene carbonate(EC) model system was created under ultra-high vacuum(UHV). The impact of Li⁺ on the binding of EC towards the C(0001) surface was studied quantitatively. Temperature programmed desorption (TPD) spectra showed that the 0.78±0.06 eV EC binding energy on neat HOPG increases to 1.19±0.10eV upon lithiation. At higher lithium loadings, temperature programmed reaction spectroscopy (TPRS) was used to track Li-metal induced EC decomposition. Condensation reactions involving Li⁺EC^- radicals were followed via C₂H₄elimination. Branching between different reaction pathways was determined through CO₂ fragment yields from decomposition products. We compare thermal pathways and branching to electrochemical pathways reported in the literature.
Thursday, April 11, 2013 03:30 PM
Characterization of Interfaces at Molecule Length Scales (02:00 PM - 05:20 PM)
Location: New Orleans Marriott
Room: Studio 3