Spring 2020

Departmental Seminars

 

January 6, 2020
10:30 AM
Room 1011, EB1
Dr. Carlos Rinaldi
University of Florida 

Nanoparticles are of interest in a variety of biomedical applications that take advantage of their small size and unique properties. Iron oxide magnetic nanoparticles are one class of nanomaterials that respond to externally applied magnetic fields due to their superparamagnetism, enabling applications in targeted and externally triggered drug delivery, magnetic actuation of cell surface receptors, nanoscale heat delivery, and imaging applications. In all these applications, the nanoparticles must navigate biological fluids, which are often composed of a complex, crowded, and confined aqueous mixture of biomacromolecules and salts, bounded by cell membranes and other tissue components. Design of magnetic nanoparticles for biomedical applications would benefit from fundamental understanding of their diffusive behavior in biological fluids. However, traditional techniques to characterize colloid diffusion often fail in biological environments due to the presence of nanoscale biomolecules, cell debris, and cells. In this talk I will summarize our work on evaluating diffusion of nanoparticles in polymer solutions and biological fluids through dynamic magnetic susceptibility (DMS) measurements and x-ray photocorrelation spectroscopy (XPCS). DMS measurements take advantage of the balance between magnetic and hydrodynamic torques on magnetically blocked nanoparticles subjected to alternating magnetic fields. The frequency spectrum of the nanoparticle response is analyzed quantitatively to calculate their rotational diffusion coefficient. The measurement relies on magnetic signals, does not require optic access, and provides reliable measurements even complex fluid environments. XPCS measurements analyze the dynamic scattering of x-rays by suspended colloids to calculate their translational diffusion coefficient. Results for diffusion of polymer grafted nanoparticles in polymer solutions, hyaluronic acid solutions, and in synovial fluid will be presented.

January 13, 2020
10:30 AM
Room 1011, EB1
Dr. Jean Goodwin
North Carolina State University

Communicating their expert knowledge is emerging as a key task for every 21st century scientist and engineer. It’s vital for good decision-making on all sorts of personal and policy questions. And it’s key in maintaining the place of expertise in our society more generally. But you don’t necessarily get much training in communicating with the public, and you may be among the quarter of the population who fear public speaking more than death!

This presentation will focus on the core thinking and planning skills you will need to build science communication into your future career, whatever path you take. We’ll discuss the answers that communication research provides to the three key questions:

  • Who is my audience?
  • What are my goals?
  • Where can I get HELP!!!

February 3, 2020
10:30 AM
Room 1011, EB1
Dr. Peter Cummings
Vanderbilt University
Gubbins Lecture

Molecular simulation plays an important role in many sub-fields of chemical engineering, just as it does in science and engineering in general. Soft matter systems (those easily deformed at room temperature – e.g., liquids, polymers, foams, gels, colloids, and most biological materials) are ubiquitous in chemical engineering, but they pose particular computational challenges since the differences in potential energy between distant configurations are on the same order as the thermal motion, requiring time and/or ensemble-averaged data to be collected over long simulation trajectories for property evaluation. Furthemore, performing a molecular simulation of a soft matter system involves multiple steps, which have traditionally been performed by researchers in a “bespoke” fashion. The result is that many soft matter simulations published in the literature are not reproducible based on the information provided in the publication, and large-scale screening (as envisaged in the Materials Genome Initiative) of soft materials systems is a formidable challenge.

To address the issues of reproducibility and computational screening capability, we have been developing the Molecular Simulation and Design Framework (MoSDeF) software suite, including the open­source mBuild (https://github.com/mosdef­hub/mbuild) and Foyer (https://github.com/mosdef­hub/foyer) packages. We will introduce MoSDeF and its capabilities in this presentation. We will also illustrate how, by combining with the Glotzer group’s Signac­flow workflow manager (https://bitbucket.org/glotzer/signac­flow), we have facilitated screening of soft matter systems over chemical/structural parameter spaces.

We will report results for two timely applications: lubrication of nanoscale devices featuring surfaces functionalized by monolayers in sliding contact, and understanding diffusion of ionic liquids in organic solvents (related to energy storage devices). In both cases, automation of the simulation through use of the MoSDeF tools enables screening and reproducibility.

BIO

Dr. Peter T. Cummings is the John R. Hall Professor of Chemical Engineering at Vanderbilt University. He also holds the position of Associate Dean for Research in the Vanderbilt University School of Engineering. For 20 years (1994-2013), he was associated with Oak Ridge National Laboratory (ORNL) at levels of effort ranging from 40 to 50%, most recently (2007-2013) as the chief scientist of ORNL’s Center for Nanophase Materials Sciences (CNMS). His research interests include statistical mechanics, molecular simulation, computational materials science, computational and theoretical nanoscience, and computational biology. He is the author of over 400 refereed journal publications and the recipient of many awards, including the 1998 Alpha Chi Sigma award, the 2010 AIChE Founders Award for Outstanding Contributions to the Field of Chemical Engineering, the 2012 Yeram S. Touloukian Award from the American Society of Mechanical Engineers, the 2013 John Prausnitz award, and the 2018 Foundations of Molecular Modeling and Simulation Founder’s Medal. He has been elected fellow of the American Physical Society, of the American Association for the Advancement of Science (AAAS), the American Institute of Chemical Engineers, and the Royal Society of Chemistry of the United Kingdom.

February 4, 2020
10:00 AM
Room 123, BTEC
Dr. Peter Cummings
Vanderbilt University
Gubbins Lecture

In order to be self-sufficient with relatively constant energy output, renewable energy sources, such as solar and wind, require that energy be stored during periods of high energy production so that it can be available during periods of low or zero energy production. Among the many choices for energy storage devices, electrical double layer capacitors (EDLCs), also called supercapacitors, are attracting considerable attention. Supercapacitors store electrical energy via ion electrosorption directly in the EDLs at the electrolyte-electrode interface, suggesting that such liquid-solid interfaces play a dominant role in the underlying energy storage mechanism and the resulting device performance. Because electrical energy in supercapacitors is stored based on physical phenomena rather than chemical reaction (as in batteries), supercapacitors have fast rates of charge/discharge and a virtually limitless number of charge cycles (unlike batteries, which are often limited to 104 or less cycles). Much of the goal of supercapacitor research is aimed at increasing the amount of energy stored (energy density is the strong point in favor of batteries), which in turn focuses attention on the electrolyte, the nature of the electrode, and the electrode-electrolyte interactions.

To date, ionic liquids (ILs) have become emerging candidates for electrolytes used in supercapacitors, due to their exceptionally wide electrochemical window, excellent thermal stability, nonvolatility, and relatively inert nature; meanwhile carbons are the most widely used electrode materials in supercapacitors, due to their high specific surface area, good electrical conductivity, chemical stability in a variety of electrolytes, and relatively low cost. To improve the energy density and the transport properties of the charge carriers in supercapacitors, carbons have been developed in diverse forms such as activated carbons, carbon nanotubes (CNTs), onion-like carbons (OLCs), carbode- derived carbons and graphene. Using molecular modeling combined with molecular experimental probes, such as SAXS, SANS, NMR, and AFM, we report on some of our investigations into the interfacial phenomena occurring between the IL electrolytes and electrodes of varying geometries to understand the energy storage mechanism of supercapacitors that rely on EDLs established at IL-electrode interfaces. In more recent work, we have been focusing on improving the dynamics of supercapacitors; in particular, we have been evaluating the role of organic solvents in increasing the diffusivity, and hence conductivity, of ionic liquid-based electrolytes, and we will report results based on computational screening of solvents using the Molecular Simulation Design Framework (MoSDeF).

BIO

Dr. Peter T. Cummings is the John R. Hall Professor of Chemical Engineering at Vanderbilt University. He also holds the position of Associate Dean for Research in the Vanderbilt University School of Engineering. For 20 years (1994-2013), he was associated with Oak Ridge National Laboratory (ORNL) at levels of effort ranging from 40 to 50%, most recently (2007-2013) as the chief scientist of ORNL’s Center for Nanophase Materials Sciences (CNMS). His research interests include statistical mechanics, molecular simulation, computational materials science, computational and theoretical nanoscience, and computational biology. He is the author of over 400 refereed journal publications and the recipient of many awards, including the 1998 Alpha Chi Sigma award, the 2010 AIChE Founders Award for Outstanding Contributions to the Field of Chemical Engineering, the 2012 Yeram S. Touloukian Award from the American Society of Mechanical Engineers, the 2013 John Prausnitz award, and the 2018 Foundations of Molecular Modeling and Simulation Founder’s Medal. He has been elected fellow of the American Physical Society, of the American Association for the Advancement of Science (AAAS), the American Institute of Chemical Engineers, and the Royal Society of Chemistry of the United Kingdom.

February 10, 2020
10:30 AM
Room 1011, EB1
Dr. Tony Ye Hu
Tulane University

Dr. Hu’s research team focuses on developing and validating integrated nanotechnique- based strategies to identify novel biomarkers in non-invasive or minimally invasive clinical samples and to translate these findings into clinical assays that provide information suitable for personalized medicine approaches. The laboratory’s goal is to fill critical gaps that persist in early disease detection, prognostic evaluation, and the real-time monitoring of treatment responses for several important infectious and chronic diseases, including tuberculosis and many cancers, in order to improve patient outcomes.

BIO

Dr. Tony Hu received his MS in Chemistry and Biochemistry in 2004, and PhD in Biomedical Engineering in 2009, both from the University of Texas at Austin. He then completed postdoctoral training in nanomedicine at the Univ. of Texas Health Science Center at Houston before his first faculty appointment in 2011. Dr. Hu is currently the Weatherhead Presidential Chair in Biotechnology Innovation in the School of Medicine, Tulane University. He is also the director of the Center of Cellular and Molecular Diagnosis. Dr. Hu previously served as professor at the Biodesign Institute at Arizona State University’s Virginia G. Piper Center for Personalized Diagnostics and at ASU’s School of Biological and Health Systems Engineering. His research focuses on developing and validating highly sensitive blood tests that rely on nanotechnology-based strategies to find previously undetectable biomarkers of diseases.

February 17, 2020
10:30 AM
Room 1011, EB1
Dr. Aaron Wheeler
University of Toronto

Microfluidics has been promoted for decades as being a potential solution to the problem of needing portable analysis systems that can be operated outside of the laboratory or in other hard-to-reach settings. There are a handful of compelling examples of this type of portable analysis (in academia and industry), but to date there has been more talk than action towards this important goal. In this presentation, I will review my research group’s work with digital microfluidics, a technique in which droplets of reagents are manipulated on open surfaces (without channels or walls). I will feature stories about the deployment of our digital microfluidic systems into two (very different kinds of) hard-to-reach settings. Finally, I will make the case that technologies like microfluidics can have greatest impact (in both easy- and hard-to-reach settings) when they are available to the widest pool of users, and will describe some (small) efforts toward this goal from my own research group.

BIO

Aaron Wheeler completed his PhD in Chemistry working with Dick Zare at Stanford University in 2003. After a postdoctoral fellowship at UCLA, Wheeler moved to Canada in 2005 to join the faculty at the University of Toronto, where he is the Tier-1 Canada Research Chair in Microfluidic Bioanalysis. Wheeler is an associate editor for the influential journal, Lab on a Chip, and is a recent recipient of the Lab on a Chip Pioneers of Miniaturization award.

February 24, 2020
10:30 AM
Room 1011, EB1
Dr. Franklin Goldsmith
Brown University

Detailed chemical kinetic mechanisms play an increasingly important role in reaction engineering. In this seminar, I will discuss some of the challenges associated with large, complex mechanisms, and how we address those challenges. Two specific cases will be highlighted. The first case focuses on the fate of fuel-bound nitrogen in low-temperature combustion. Low-temperature compression-ignition engines represent a new class of internal combustion engines that could meet stringent fuel economy and emissions requirements. These engines often rely additives to improve their performance, but the emissions implications of those additives are poorly understood. The second case focuses on high-temperature catalysis and the problems associated with developing a thermodynamically consistent mechanism for homogeneously/heterogeneously coupled systems. We will present software that we have developed, RMG-Cat, that automatically explores reaction pathways on a catalytic surface, but only retains the most important reactions. We focus on catalytic combustion of methane on platinum as a case study.

BIO

Dr. Franklin Goldsmith joined the School of Engineering at Brown University in January, 2014. His research focuses on theoretical, computational, and experimental methods in chemical kinetics. Most of the Goldsmith Group’s work is in combustion chemistry, but the group also is active in heterogeneous catalysis, energetic materials, propellants, and atmospheric chemistry. Goldsmith received a B.A. in Philosophy from the University of North Carolina, a B.S. in both Chemical Engineering and Applied Mathematics from North Carolina State University, and was a Fulbright Scholar in Mathematics in Freiburg, Germany. He obtained his Ph.D. in Chemical Engineering from the Massachusetts Institute of Technology. Goldsmith spent two years in Berlin as an Alexander von Humboldt Scholar in Inorganic Chemistry at the Fritz-Haber Institute of the Max Planck Society, followed by one year as an Argonne Director’s Fellow in Theoretical Chemistry at Argonne National Laboratory.

March 2, 2020
10:30 AM
Room 1011, EB1
Dr. Gregory Hudalla
University of Florida

The coordinated assembly of biomolecules throughout the natural world provides a fascinating blueprint to design new materials for biomedicine and biotechnology. Our research program employs simple molecular assembly motifs, namely coiled-coil peptide scaffolds and beta-sheet peptide nanofibers, to organize proteins and carbohydrates into precise supramolecular architectures. In one application, we develop recombinant fusion “assembly tags” to install enzymes into peptide nanofibers that entangle into injectable hydrogels. In a second application, we develop a strategy to create nanofibers with tailored composition of carbohydrates as the basis for synthetic mimics of extracellular matrix glycoproteins. The utility of this technology is illustrated by creating nanofibers that can modulate the activity of galectins, a family of carbohydrate-binding extracellular signaling proteins, as well as mimic the barrier function of mucins. More recently, we’ve shown that tailoring glycosylation of peptide nanofibers can encode hierarchical order by stabilizing weak carbohydrate-carbohydrate interactions. In a third application, we are developing strategies to anchor biotherapeutics, such as anti-inflammatory enzymes, to specific tissue locations by engineering them to bind to abundant cell surface and extracellular matrix carbohydrates. Finally, we are creating a cell signaling rheostat by employing coiled-coil scaffolds to kinetically trap protein ligands in assemblies with precisely defined numbers of signaling subunits. Together, these approaches demonstrate the enormous potential of molecular assembly to advance the capabilities of biomaterials and biotherapeutics finding increasing use in medical and biotechnology applications.

BIO

Dr. Hudalla received a B.S. in Chemical Engineering from the Illinois Institute of Technology in 2004, a M.S. in Biomedical Engineering from the University of Wisconsin in 2006, and a Ph.D. in Biomedical Engineering from the University of Wisconsin in 2010. Dr. Hudalla was a post-doctoral fellow at the University of Chicago and Northwestern University from 2010-2013 through support from an NIH National Research Service Award. Dr. Hudalla is currently an Associate Professor and a University Term Professor in the J. Crayton Pruitt Family Department of Biomedical Engineering at the University of Florida, where he has been since 2013. Dr. Hudalla’s research program develops biotherapeutics and biomaterials with new or improved functional properties via molecular engineering and self-assembly. Dr. Hudalla has authored more than 25 papers, is co-editor of the book “Mimicking the Extracellular Matrix: The Intersection of Matrix Biology and Biomaterials”, and holds 2 US patents, with another 10 currently pending. Dr. Hudalla has received the Cellular and Molecular Bioengineering Young Innovator award, the Journal of Materials Chemistry B Emerging Investigator award, a National Science Foundation RAISE award, the National Institute of Biomedical Imaging and Bioengineering Trailblazer award, the National Science Foundation Career award, the University of Wisconsin Alumni Early Career Achievement award, and the National Institute of General Medical Sciences Maximizing Investigators’ Research Award.

March 5, 2020
11:00 AM
Room 123, BTEC
Dr. Millicent Sullivan
University of Delaware

A wealth of potential therapeutic opportunities remains untapped within cells. For example, DNA delivered to the nucleus can interact with the native nuclear machinery to stimulate cellular production of essentially any protein of interest, whereas short interfering RNA (siRNA) delivered to the cytosol can initiate gene silencing (and the corresponding lack of protein production). Because of the exquisite specificity of these processes and the fundamental role for proteins in biology, nucleic acid medicines have unparalleled potential to modulate tissue regeneration and cure a wide range of devastating diseases, including cancers, cardiovascular diseases, and infectious diseases, yet no nucleic acid products are currently marketed. Meanwhile, various intracellular organelles are also the therapeutic targets for numerous small molecule medicines such as chemotherapies, but poorly controlled delivery regimens often cause severe side effects, multi-drug resistance phenotypes, and in some cases, a complete lack of efficacy.

Our group addresses challenges in therapeutic delivery by coupling principles in molecular design, molecular self-assembly, and chemical reaction kinetics with principles of cell and extracellular matrix (ECM) biology and the cell-material interface. In particular, soft materials (e.g. polymers and peptides) exhibit enormous chemical and mechanical tunability and have been self- assembled by our group and others into a versatile array of gene and drug-loaded nanostructures. We are particularly interested in developing nature-inspired approaches to harness native gene delivery and regulation mechanisms, and to actively control self-assembly vs. disassembly in gene and drug-loaded structures. We develop and use nanoscale materials to understand and probe cellular “unit ops,” with long-term applications including targeted drug delivery for prostate and breast cancer, and gene therapy for wound and tissue repair.

BIO

Dr. Millicent Sullivan is a Professor and Associate Chair in Chemical & Biomolecular Engineering at the University of Delaware, and a Joint Professor in Biomedical Engineering at UD. Sullivan graduated from Princeton University with a B.S.E. degree in Chemical Engineering and a Certificate in Engineering Biology in 1998. Subsequently, she attended Carnegie Mellon University as a Clare Boothe Luce Graduate Fellow, where she earned her Ph.D. degree in Chemical Engineering with Professor Todd Przybycien in 2003. As a Ruth L. Kirchstein NIH postdoctoral fellow, Sullivan worked with Professor E. Helene Sage in the Matrix Biology/Hope Heart Program of the Benaroya Research Institute. In 2006, Sullivan moved to the University of Delaware.