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2016 Seminars

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Spring 2016 Seminars

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Friday, April  8, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Dr. Zijie Yan

Department of Chemical and Biomolecular Engineering
Clarkson University

will speak on

Optical Trapping and Manipulation of Colloidal Nanocrystals

Abstract:

Size- and shape-controlled synthesis of colloidal nanocrystals has been feasible for many materials using wet chemistry methods, yet spatial and temporal control of these nanomaterials remains a challenge due to intense Brownian motion of nanoparticles in solution. The ability to manipulate small objects is essential in studying many microscopic phenomena, not only in colloid science, but also in molecular biology and nanomanufacturing. In this seminar, I will introduce the techniques and mechanisms to control nanomaterials with light, including detailed discussions of the interactions of light with plasmonic nanostructures. In particular, I will describe holographic optical tweezers that use structured laser beams to tailor the optical trapping of specific silver nanostructures, and the light-induced self-assembly of silver nanoparticles due to significant electrodynamic interactions (i.e., “optical binding”) in simple optical fields. The possibility to control and manipulate microscopic objects provides new opportunities to study the light-matter interaction at the nanoscale, and enables improved technologies for studies in chemistry & biomolecular science.

Figure 1

Dr. Zijie Yan

Professor He Dong (right) with Dr. Zijie Yan

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Friday, April  15, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Professor Richard A. Gross

Rensselaer Polytechnic Institute (RPI), Constellation Chair: Biocatalysis and Metabolic Engineering,  Center for Biotechnology and Interdisciplinary Studies; Professor, Department of Chemistry and Biology, Professor of Biomedical Engineering, 4005B BioTechnology Bldg., 110 8th Street, Troy, N.Y. 12180

http://www.poly.edu/grossbiocat/; grossr@rpi.edu

will speak on

The expanding role of enzyme catalyzed synthesis of polymers, surfactants and peptides

Abstract:

Cell-free lipase biocatalysis, due to the mild temperatures at which they catalyzed reactions as well as their extraordinary selectivity, provide numerous benefits when synthesizing polyesters, polycarbonates and polyamides. As an example, the use of lipase-catalyzed condensation polymerizations using multifunctional building blocks such as glycerol and sorbitol provide a versatile family of functional polymers.  Crosslinking is avoided during lipase-catalyzed polymerizations due to the steric hinderance at active sites. Furthermore, mild polymerizations allow the incorporation along chains of chemically sensitive moieties. Biocatalysis using whole cells provides important new routes to biobased monomers and biosurfactants from renewable feedstocks. As an example, the biosynthesis and properties of modified sophorolipids will be discussed.  The polymerization of lactonic sophorolipids by ring-opening metathesis polymerization (ROMP) leads to highly functional bioresorbable polymers.  Poly(sophorolipids) are cytocompatible with human mesenchymal stem cells (h-MSCs) and can induce osteogenic cell lineage progression.  Molecular editing of natural sophorolipids has been used to develop a library of low molar mass sophorolipid analogs. Examples of how this approach allows the tuning of sophorolipid interfacial and biological properties will be discussed.  Finally, our group is developing mild and efficient protease-catalyzed routes for peptide synthesis. Examples will be given of protease-catalyzed routes to peptides with various properties such as self-assembly, antimicrobial and metal chelation.  A future perspective will be given on the potential of protease-catalysis for peptide synthesis.

Professor Richard A. Gross

Professor He Dong (right) with Professor Richard A. Gross

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Friday, April  8, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Professor Vincent Conticello

Department of Chemistry
Emory University

will speak on

Peptide and Protein Nanomaterials: The Design Challenge

Abstract:

Structurally defined materials on the nanometer length-scale have been historically the most challenging to rationally construct and the most difficult to structurally analyze. Sequencespecific biomolecules, i.e., proteins and nucleic acids, have advantages as design elements for construction of these types of nano-scale materials in that correlations can be drawn between sequence and higher order structure, potentially affording ordered assemblies in which functional properties can be controlled through the progression of structural hierarchy encoded at the molecular level. However, the predictable design of self-assembled structures requires precise structural control of the interfaces between peptide subunits (protomers). In contrast to the robustness of protein tertiary structure, quaternary structure has been postulated to be labile with respect to mutagenesis of residues located at the protein-protein interface. We have employed simple self-assembling peptide systems to interrogate the concept of designability of interfaces within the structural context of nanotubes and nanosheets (see below). These peptide systems provide a framework for understanding how minor sequence changes in evolution can translate into very large changes in supramolecular structure, which provides significant evidence that the designability of protein interfaces is a critical consideration for control of supramolecular structure in self-assembling systems.

Figure 1 and Figure 2

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Friday, April 1, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 213

Jesse Pokrzywinski

Ph.D. Student
Clarkson University

will speak on

“Waste Milk Derived Carbons with Surface Area Surpassing Graphene Offer Extraordinary Supercapacitance”

Abstract:

Here we demonstrate a facile template-free synthesis route to create macroscopically monolithic carbons that are both highly heteroatom rich (>10% N,O) and highly microporous (SA up to 3074 m2 g-1, 90vol% useful micropores and small mesopores). While such materials, which are derived from waste milk, are expected to be useful in a variety of applications, they are extremely promising for electrochemical capacitors based on aqueous electrolytes.  The Milk Activated Carbons (MAC) demonstrate a specific capacitance > 700 F g-1 at 0.25A g-1and > 350 F g-1 at 10 A g-1 in their optimized state. These are among the highest values reported in literature for carbon-based electrodes, including for systems such as templated carbons and doped graphene. We show that MACs serve as ideal electrode materials for supercaps; symmetrical cells employing neutral electrolytes and MACs demonstrate > 2.5X higher specific energy as compared to one employing a state-of-the-art commercial activated carbon. Specific energies (active mass normalized) of >60 Wh kg-1 at 230 W kg-1 and >40 Wh kg-1 at 1900 W kg-1 are achieved.  The symmetrical cell performance is among the best in literature for symmetrical aqueous systems, and actually rivals cells operating with a much wider voltage window in organic electrolytes.

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Friday, March 25, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Professor Omar K. Farha

Department of Chemistry
International Institute of Nanotechnology Northwestern University

will speak on

Catalytic Metal-Organic Framework Materials

Abstract:

Metal–organic frameworks (MOFs) are an emerging class of solid-state materials built up from metal-based nodes and organic linkers. They exhibit permanent porosity and unprecedented surface areas which can be readily tuned through coordination chemistry at the inorganic node and/or organic chemistry at the linkers. The high porosities, tunability, and stability are highly attractive in the context of catalysis. As exemplified by many catalytic enzyme assemblies in nature, site-isolation is a powerful strategy for performing catalytic reactions. MOFs provide an exciting platform for deploying catalysts in a site-isolated fashion and the cavities surrounding them can be engineered to conceptually mimic enzymes. This talk will address new advances in the synthesis and catalytic activity of MOF materials developed at Northwestern University.

Professor Mario Wreidt (right) with Professor Omar K. Farha

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Friday, March 11, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Devika Channaveerappa, M.S.

Ph.D. Student
Clarkson University

will speak on

“Functional Investigation of Human Jumping Translocation Breakpoint (hJTB) Protein by Mass Spectrometry-based Proteomics”

Abstract:

Human JTB (hJTB) is a gene located on the human chromosome 1 at q21 which is involved in the unbalanced translocation in various types of cancer. JTB protein is ubiquitously present in normal cells and is found to be overexpressed in different types of cancer including prostate and breast cancer. Hence this protein could be a tumor biomarker for different types of malignancies and a potential target for their treatment. However, the biological function and the pathway through which this protein causes increased cell growth and proliferation is not entirely clear. Investigation and comparison of the proteomes of cells with upregulated and downregulated JTB can be a good approach to understand the function of the protein and also its contribution to tumorigenesis. In this study, MCF7 breast cancer cell lines were transfected with the sense and antisense orientation of the JTB cDNA in HA, His and FLAG tagged CMV expression vector. The expression of JTB was confirmed by western blotting. Proteins extracted from transiently transfected cells were separated using SDS-PAGE and the in-gel digested peptides were analyzed by a Nano Acquity UPLC coupled with Xevo G2 Mass Spectrometer. Data analysis was done using Mascot server and Scaffold 4.1 software. In addition, two other JTB isoforms are currently investigated and their possible cellular function(s) will be compared with the functions of the wild type JTB. These studies could help us elucidate the mechanism through which JTB induces cell proliferation and test the JTB protein as a potential drug target for malignancies with overexpression of the protein.

Professor Costel Darie (right) with Ph. D. Student Devika Channaveerappa

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Friday, March 4, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Professor Ryan C. Hayward

Polymer Science and Enginering
The University of Massachusetts Amherst

will speak on

Programming shape and structural color with polymer nanocomposites

Abstract:

Our group seeks to fabricate and understand the behavior of reprogrammable materials, particularly those with functions mimicking the complex adaptive responses common in nature. Polymer nanocomposites, which can combine the chemical versatility and large strain responses possible with polymers, with the attractive optical, electronic, or magnetic characteristics of inorganic nanoparticles, offer unique opportunities in this regard.  We have recently studied two main classes of responsive nanocomposite materials. In the first case, we seek to harness spatially non-uniform stresses within thin polymer sheets and multilayers to drive out-of-plane buckling modes that can control the three-dimensional shapes of materials. Light-responsive elements within such constructs offer possibilities for dynamically reconfigurable materials that can be remotely controlled, with high resolution in both space and time. We have recently studied several examples of hydrogel-based sheets and multilayers where photoswitching is enabled through photothermal actuation of nanocomposite gels and liquid crystalline polymers. In the second case, we take advantage of interference of light reflected from within periodically structured dielectric media to define responsive photonic coloration. With multilayer polymer films alone, the modest contrast in refractive index means that many layers are required to achieve highly efficient reflection. Thus, the incorporation of high refractive-index inorganic nanoparticle species represents an attractive means to improve performance while simplifying fabrication.

Professor Devon Shipp (right) with Professor Ryan C. Hayward

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Friday, February 26, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212

Gonca Bülbül

Ph.D. Student
Clarkson University

will speak on

Portable Technologies for Point of Care Testing (POCT)

Abstract:

The need for portable Point-of-Care Testing (POCT) devices that can provide rapid, low cost and continuous measurement of analytes in the biomedical, food and environmental monitoring fields is growing. This seminar will discuss development, fabrication, analytical characterization and deployment of POCT devices. The second part of the seminar will describe our recent efforts to develop a new portable technology using redox active nanoparticles as colorimetric agents and signal amplifiers to reduce the number of measurement steps and increase detection sensitivity and portability of bioassays. Several applications of this platform for monitoring enzymatic and bioaffinity reactions in a single step procedure will be discussed. The method takes advantage of the reactivity of cerium oxide nanoparticles with products of the enzyme catalyzed reaction, resulting in charge transfer complexes with very strong absorption characteristics. The developed assay is easy-to-use and does not require labeled reagents, secondary enzymes or soluble dyes. The proposed assay can eliminate multistep procedures and minimize problems associated with the poor stability of substrates and enzyme labels of conventional enzyme assays. The assay has been adapted to a paper platform and has demonstrated functionality for detection of enzyme activity in human serum. This sensing concept can find wide applications as a general approach for improving sensitivity and simplifying detection schemes of colorimetric bioassays, e.g. enzyme, gene, immuno and aptamer assays and related affinity sensing methods.

Bülbül Seminar

Professor Silvana Andreescu (right) with Ph.D. Student Gonca Bülbül 

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Friday, February 19, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Brian E. Fratto

Ph.D. Candidate

Clarkson University

will speak on

“Controlled Logic Gates – Realizing the Switch Gate and Fredkin Gate utilizing Enzyme-Biocatalyzed Reactions in Flow Cells”

Abstract:

Progress in the field of unconventional computing based on molecular and biomolecular systems, has fostered the ability to re-create many systems that are able to mimic their electronic counterparts by performing Boolean logic operations.  The ability to organize enzymatic systems by using a network of flow cells, each modified with one enzyme that biocatalyzed one chemical reaction has permitted the novel mimicking of switchable logic gates in addition to specific reversible logic gates. These gates include the Double Feynman Gate, Toffoli Gate, Peres Gate and switchable OR, NXOR, and NAND systems. Further utilization of the modular fluidic devices has not only allowed for the realization these systems, but has also made it possible to bypass many difficulties that hinder traditional biocomputing systems. In addition to the advantages of clocking and separation of channels, the use of modular fluidic devices also allows for the routing of Data signals between different output channels.  In the specific case of the Switch Gate and Fredkin Gate, the modular design of the enzyme-based systems, which have been realized in the flow device, has allowed for easy reconfiguration of the logic system. Thus, allowing the simple extension of the logic operation from the 2-input/3-output channels in the Switch Gate to the 3-input/3-output channels in the Fredkin gate.

Fratto Seminar

Professor Evgeny Katz (right) with Ph.D. Candidate Brian E. Fratto

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Friday, February 12, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Dr. Jason B. Benedict

Department of Chemistry

University at Buffalo, the State University of New York

will speak on

“Watching crystals work: Structural dynamics of metal-organic frameworks”

Abstract:

Photochromic technologies have the potential to transform traditionally passive materials into active materials which change their chemical or electronic properties in response to light stimulus. New photochromic materials are being synthesized and reported at an extremely rapid rate driven in large part by the numerous potential applications for these advanced materials including molecular switches, sensors, data storage, photomechanical devices and even biological switches. One of the newest emerging applications for photochromic technologies being developed in the Benedict research lab is the development of photo-responsive metal-organic frameworks (MOFs): highly porous crystalline frameworks capable of undergoing structural reorganization upon application of light. The Benedict group is also developing cutting edge in situ X-ray diffraction techniques to study the structural reorganization, both photo-induced and through guest exchange, under ‘real world’ conditions in order to develop a molecular level understanding of the processes that occur within these important materials.

Professor Mario Wreidt (right) with Dr. Jason B. Benedict

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Friday, February 5, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Dr. He Dong

Dept. of Chemistry & Biomolecular Science

Clarkson University

will speak on

“Supramolecular Assembly of Peptidic Biomaterials: From Molecular Design and Understanding to Therapeutics Development”

Abstract:

Peptide-based supramolecular assemblies represent an important class of soft nanomaterials with hierarchical structural control down to the molecular level. The well-defined molecular structure plays important roles in regulating supramolecular structure, property and various biological activities. In this seminar, I will discuss two self-assembling systems based on de novo designed peptides and their therapeutic applications. The first system is inspired by amyloid nanofibers. By manipulating the attractive and repulsive force through primary sequence variation, nanofibers were formed with desirable features of controlled assembly, nanostructured dimensions, atomically precise localization of chemical functionality ideal for anisotropic nanocarrier design. In a second example, I will discuss a new design of artificial proteins through self-assembly of a two-component chimeric peptide. The synthetic peptide self-assembled into discrete tetrahedron-like protein nanoparticles driven by a combination of symmetry controlled molecular packing and geometric constraint. These preliminary findings are expected to help establish a fundamental understanding of how molecular design impacts folding and assembly of multi-component peptides. It will also help develop more sophisticated peptide-based molecular toolkits for the construction of discrete protein-like nanoparticles with well-defined molecular pattern, increased complexity and diverse functionality.

He Dong Seminar

Dr. He Dong (left) with graduate students Linhai Jiang (center) and Dawei Xu (right). 

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Friday, January 29, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Professor Dan Goia

Dept. of Chemistry & Biomolecular Science

Clarkson University

will speak on

“Room temperature sinetrable silver nanoparticles for printable electronics”

Abstract:

Noble metals nanoparticles are widely used in electronics, catalysis, optics, medicine, biology, thin film solar cells, and transparent conductive coatings. The technological advances of all these applications depend on the ability to control the particles size, size distribution, morphology, internal structure, and surface properties. In this regard, there is a strong interest in developing simple, cost effective, and scalable preparation methods capable of synthesizing materials with characteristics that address the specific requirements of a wide range of practical applications.

Inkjet printable conductive structures based on silver nanoparticles are rapidly integrated not only in the traditional electronic components and devices but also in novel applications in displays, sensors, and solar cells. In the case of flexible or thermally sensitive substrates, lowering the sintering temperature of Ag particles is the main technology driver. For this reason, developing particles that could be consolidated into electrically conductive elements/structures at ambient temperature has been for some time now the ‘Holy Grail’ of the electronic industry. The presentation will give an overview of a new type of silver nanoparticles that can form electrically conductive layers at room temperature. The research strategy used in the development of the particles will be discussed in detail and their unique properties will be reviewed. The ability to generate at room temperature (and matter of minutes) highly conductive patterned layers on various substrates will be demonstrated to the audience. Finally, new and exciting applications in existing and emerging technology fields will be proposed.

Dan Goia Seminar 2016

Professor Dan Goia (left) with Dr. Ajeet Kumar

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Friday, January 22, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Professor Devon A. Shipp

Dept. of Chemistry & Biomolecular Science

Clarkson University

will speak on

“Polyanhydrides: Versatile Biomaterials for Drug Delivery, Shape Memory Polymers, Self-Healing Materials and Nanoparticles”

Abstract:

Polyanhydrides have found a niche in the degradable polymer field, largely because they often undergo surface erosion, but demanding synthesis conditions have held them back from widespread use. To address this problem, we have developed novel polyanhydrides that are based on thiol-ene ‘click’ polymerization, an easy to conduct step-growth mechanism of polymerization that can be applied to make materials that have relatively uniform network structure. Further, thiol-ene ‘click’ polymerization is robust, can be photo-, redox- or thermally-initiated and may use a wide variety of monomers. Thus, these have real potential in a variety of applications, including orthopedics and drug delivery.

Discussed in this presentation will the be the synthesis of elastomeric and semi-crystalline polyanhydrides that have controllable degradation rates, and how this approach to network polyanhydrides can provide significant flexibility in tailoring characteristics such as crosslink density, functionality and hydrophilicity. In particular, it will be shown that polyanhydrides can be used in applications such as drug delivery, can also behave as shape memory polymers, exhibit self-healing properties and can be produced as nanoparticles.

Professor Devon Shipp (center) with graduate students Olivia Durham (left) and Kelly Tillman (right)

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Friday, January 15, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Jennifer Ritz

Ph.D. Candidate

Clarkson University

will speak on

“Investigations into the Synthesis of Thiolate-Protected Metal Nanoparticles”

Abstract:

The two-phase Brust-Schiffrin synthesis was developed in 1994 to produce alkanethiolate-protected gold nanoparticles (1-10 nm) that are dispersible in organic media.  It has since been widely employed for a variety of different metals because the products are typically highly stable, relatively monodisperse, and can be dried, stored, and redispersed without significant change.  In these syntheses, metal halide anions are phase-transferred from water to toluene using the phase-transfer agent tetraoctylammonium bromide, generating an ion-pair complex in the organic phase. This phase is then isolated and thiol ligands are added. Finally, a two-phase reduction process is initiated with the addition of an aqueous solution of sodium borohydride.

Over the years, these nanoparticles have been studied extensively by several groups, but little attention has been paid to developing thorough mechanistic understanding of the relatively complex, three-step syntheses for various metals. As a result, synthetic control is currently lacking. In this seminar, several mechanistic studies into the Brust-Schiffrin synthesis of thiolate-protected Pd nanoparticles will be presented.

Additionally, a novel method for the single-phase synthesis of organosoluble thiolate-protected nanoparticles of several different metals (Au, Pd, Ag) is presented here.  Ion-pair complexes of tetraoctylammonium cation and different metal-halide anions are reacted in toluene with an organosoluble reductant in the presence of alkanethiol. This facile, single-step reaction utilizes stable, well-defined precursor species and yields monodisperse nanoparticles comparable to those produced using the more complicated, multistep, two-phase methods.

Professor Paul Goulet (right) with Ph.D. Candidate Jennifer Ritz

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Friday, January 8, 2016

3:30 p.m.
Bertrand H. Snell Hall Room 212
Professor David Mitlin

Chemical & Biomolecular Engineering and Mechanical Engineering

Clarkson University

will speak on

“Coupling in-situ TEM and ex-situ analysis to understand heterogeneous sodiation of antimony”

Abstract:

We employed an in-situ electrochemical cell in the transmission electron microscope (TEM) together with ex-situ time-of-flight, secondary-ion mass spectrometry (TOF-SIMS) depth profiling, and FIB - helium ion scanning microscope (HIM) imaging to detail the structural and compositional changes associated with Na/Na+ charging/discharging of 50 and 100 nm thin films of Sb. TOF-SIMS on a partially sodiated 100 nm Sb film gives a Na signal that progressively decreases towards the current collector, indicating that sodiation does not proceed uniformly. This heterogeneity will lead to local volumetric expansion gradients that would in turn serve as a major source of intrinsic stress in the microstructure. In-situ TEM shows time-dependent buckling and localized separation of the sodiated films from their TiN-Ge nanowire support, which is a mechanism of stress-relaxation. Localized horizontal fracture does not occur directly at the interface, but rather at a short distance away within the bulk of the Sb. HIM images of FIB cross-sections taken from sodiated half-cells, electrically disconnected and aged at room temperature, demonstrate non-uniform film swelling and the onset of analogous through-bulk separation. TOF-SIMS highlights time-dependent segregation of Na within the structure, both to the film-current collector interface and to the film surface where a solid electrolyte interphase (SEI) exists, agreeing with the electrochemical impedance results that show time-dependent increase of the films’ charge transfer resistance. We propose that Na segregation serves as a secondary source of stress relief, which occurs over somewhat longer time scales.

Professor Mario Wreidt (left) and Professor David Mitlin