Chemistry Seminars & Events

Link to Chemistry seminar recordings

Upcoming Events

Tian (Autumn) Qiu

Tian (Autumn) Qiu, Ph.D.
Beckman Institute
University of Illinois at Urbana-Champaign
Host: Professor Michael Bowser

Abstract

Exploring Molecular Mechanisms of Nano-Bio and Host-Microbe Interactions

The dynamics between the environment, host and microbes have huge implications for both sustainability and human health. Understanding the molecular basis of how microbiota impact the host response to environmental exposure are critical to develop effective strategies for risk assessment, pollution control and precision medicines. In this seminar, I will introduce my previous work on nano-bio and host-microbe interactions, building towards my future research program to decipher the molecular basis of the environment-host-microbe interactions. The rapidly advancing field of nanotechnology poses challenges for timely and predictive risk assessment of highly reactive nanomaterials being released into the environment. Focusing on an emerging nanoscale battery material, we investigated DNA damage as a shared toxicity mechanism in two bacteria and revealed unprecedented details on DNA modification after nanomaterial exposure as well as biological responses relating to DNA damage. Expanding my research to the host-microbe interactions, my current work investigates the role of D-amino acids, particularly D-alanine (D-Ala), as microbe-originated signaling molecules in the microbiome-gut-brain axis. Using nematode Caenorhabditis elegans and Escherichia coli bacterial mutants, I found impact of bacterial D-Ala synthesis and metabolism on animal phenotypes under normal condition and high glucose exposure. Using germ-free mice, I revealed biodistribution and sources of D-Ala in higher animals. As my previous studies have provided new biomarkers for nanomaterial risk assessment and indicated new targets for microbiota-mediated intervention of diseases, my future research will combine my previous trainings to investigate the molecular basis of the environment-host-microbe interactions.

Tian (Autumn) Qiu

Dr. Tian (Autumn) Qiu completed her BS in Chemistry at Peking University in 2012 and PhD in Chemistry at University of Minnesota in 2018. Her PhD work focused on understanding nanotoxicity mechanisms to environmental bacteria at the molecular level with bioanalytical tools in the laboratory of Prof. Christy Haynes as part of the Center for Sustainable Nanotechnology. From 2018 to 2021, she was a Beckman Postodctoral Fellow at University of Illinois, Urbana-Champaign, working with Prof. Jonathan Sweedler and other collaborators on exploring role of D-amino acids in the microbiome-gut-brain axis using animal and microbial models. She is currently continuing her work as a Postdoctoral Research Associate in the Sweedler Lab.

Kevin D. Clark

Kevin D. Clark, Ph.D.
Beckman Institute
University of Illinois at Urbana-Champaign
Host: Professor Michael Bowser

Abstract

Characterizing RNA Modifications in the Central Nervous System and Single Neurons:
Strategies in Sample Preparation and Mass Spectrometry

Apart from the four canonical nucleotides of RNA (A, U, G, and C), an expanding collection of over 150 RNA modifications exists that substantially diversifies the RNA code. Known as the “epitranscriptome,” these unusual chemical modifications to RNA range in complexity from simple methylations to conjugation with cellular metabolites and are enzymatically deposited/removed with sequence specificity to control the biophysical properties of cellular RNA biopolymers. However, characterizing RNA modifications in the central nervous system (CNS) has been limited by the complexity of animal models and lack of analytical methods capable of simultaneously detecting multiple modified RNAs in small-volume samples. These shortcomings have rendered the field of RNA modifications unable to account for the heterogeneous distribution of epitranscriptomic marks that potentially exists across the CNS and in single neurons. In this presentation, I will describe how our recent efforts to develop sample preparation and mass spectrometry approaches for the analysis of modified RNAs are beginning to reveal a previously uncharacterized link between dynamic RNA modifications and CNS function.

Kevin Clark

Kevin Clark received his Ph.D. in Analytical Chemistry from Iowa State University in 2018 and was awarded a 2018 Beckman Institute Postdoctoral Fellowship to study RNA modifications in the central nervous system (CNS) with Prof. Jonathan Sweedler and Prof. Rhanor Gillette. Now a postdoctoral research associate in Prof. Sweedler’s lab, Dr. Clark is developing separations and mass spectrometry methods for profiling RNA modifications in single neurons to better understand how they contribute to CNS function.

Paul Ohno

Paul Ohno, Ph.D.
Schmidt Science Fellows
Environmental Fellow, Harvard University

Abstract

Charged interface and atmospheric aerosol properties via spectroscopy

Chemical and physical processes at charged interfaces play a key role in environmental, biological, and technological systems. Yet, the relative scarcity of interface-selective experimental techniques has left open important questions regarding molecular-level structure and composition in a range of interfacial systems. Second harmonic generation (SHG) has become a workhorse interface-selective technique to characterize interfacial electrostatics. However, interpretation of SHG experiments has long been complicated by an inability to experimentally separate two terms that contribute to the total SHG signal. Here, I describe how the detection of not only SHG amplitude, but also its optical phase, enables separation and quantification of these two terms. The first term can then be used as an experimental benchmark for atomistic simulations of interfacial structure and composition, while the second term is proportional to interfacial potential and thus represents an “optical voltmeter”. I describe the design of an apparatus capable of measuring this optical phase from buried interfaces and demonstrate the application of this method to characterize oxide:water and lipid bilayer:water interfaces. Atmospheric aerosol particle phase state represents another property that has remained challenging to experimentally characterize due to the small size, low density, and delicate nature of the particles. Aerosol particles can undergo liquid-liquid phase separation (LLPS), impacting atmospheric processes including gas-particle partitioning, solar radiation scattering, and cloud nucleation. Here, I describe the first realization of an experimental technique capable of directly probing LLPS in particles of atmospherically-realistic sizes while they remain in suspension. Solvatochromic probe molecules are incorporated into the particles and their fluorescence emission is used to determine particle phase state. Differences in separation relative humidity (SRH) values measured here and previously reported SRH values from optical microscopy of much larger particles on substrates underscore the utility and importance of the technique and motivate future studies into the size dependence of LLPS in the atmosphere. Finally, I comment on the necessity of direct experimental characterizations of aerosol particle surfaces and interfaces to gain a comprehensive understanding of particle processes, properties, and impacts on air quality and climate.

Research

Paul’s overall scientific research interests revolve around the environment, sustainability, and chemistry. He is inspired by his childhood in the beautiful state of Maine and observations of the impacts of human activities on the natural environment around him.

Paul Ohno

Paul Ohno is a physical chemist studying the physical and chemical properties of secondary organic aerosol particles and the implications of these properties for the climate system.

Paul earned his AB in Chemistry from Princeton University in 2014 and his PhD in Chemistry from Northwestern University in 2019. During his PhD studies, he used laser spectroscopy to measure fundamental properties of aqueous interfaces so as to better understand, predict, and control chemical processes that occur there, like groundwater pollutant capture at the mineral/water interface.

As an Environmental Fellow, Paul works with Professor Scot Martin of the John A. Paulson School of Engineering and Applied Sciences and the Department of Earth and Planetary Sciences. Their work focuses on developing and applying spectroscopic techniques to directly determine physical and chemical properties, such as viscosity and diffusivity, of secondary organic aerosol particles while they remain in suspension. Paul is also a 2019 Schmidt Science Fellow.

Chao Sun

Chao Sun, Ph.D.
Max Planck Institute for Brain Research
Frankfurt, Germany
Host: Professor Michael Bowser

Abstract

Neuronal Protein Synthesis and Degradation Machines

A single neuron hosts ~10000 synapses in its complex dendritic and axonal arbour. Its protein logistics is run by amazing molecular machines put together with exquisite precision, such as ribosomes (protein-synthesis machines) and proteasomes (protein-degradation machines). Meanwhile, protein synthesis and degradation is essential for information storage in the brain. How do protein-synthesis & -degradation machines meet the huge demands of parallel processing by numerous synapses? To investigate this, I visualized protein -synthesis & -degradation machines as well as newly synthesized proteins near numerous synapses using quantitative, multiplexed, single-molecule localization microscopy. Combined with metabolic labelling, biochemistry, and synaptic-activity manipulations, these studies mapped and measured the subcellular protein-synthesis & -degradation capacity in complex neurons. The single-molecule resolution further affords intriguing insights into the subcellular adaptation of molecular machine assembly and function.

Chao Sun

Dr. Chao Sun is an EMBO & HFSP postdoctoral fellow in Prof. Erin M. Schuman's lab at the Max Planck Institute for Brain Research in Frankfurt, Germany. He uses quantitative, multiplexed super-resolution microscopy to investigate the molecular resource supply for the vast population of synapses associated with a single neuron. Chao obtained his PhD with Prof. William R. Dichtel at Cornell University (2013-2016) and later at Northwestern University (2016-2018). where he designed and manipulated molecular interactions to interface two-dimensional materials and molecular analogues for creating smart nano- materials and devices. His future research continues to focus on understanding and creating molecular systems that can 'think'.

Davita Watkins

Professor Davita L. Watkins
Department of Chemistry and Biochemistry
University of Mississippi
Host: Professor Tim Lodge

Abstract

Supramolecular Polymer Hybrids: Linear-Dendritic Block Colpolymers (LDBCs) as Novel Strategies for Theranostic Nanomedicine

The ability to control molecules and understand their organization into discrete nanoscale arrays that exhibit unique properties affords the opportunity for transformative advances in chemistry and material science. Specifically, for biomaterials and nanomedicine, structural and chemical variations at the molecular level will influence the morphology and mechanical properties as well as the stability and degradation rates of the resulting material. Herein, a library of self-assembling linear-dendritic block copolymers (LDBCs) comprised of a hydrophilic polyamide-based dendrimer covalently linked to a hydrophobic linear polyester will be highlighted. These polymers are shown to be capable of forming a variety of supramolecular aggregates in water—particularly those possessing a biomimetic nature. In this lecture, the synthesis and characterization of the LDBCs library as well as their resulting nano- aggregates will be discussed. Results of this study demonstrate the significant contribution of “bottom-up” approaches towards efficient materials for bio-imaging and theranostic nanomedicine.

Research

Designing vesicles with features such as uniform size distribution, biocompatibility, and tailored transport properties, presents a challenge for the fields of nanotechnology and nanomedicine.   Dendrimers have shown to be promising delivery vehicles in biomedical applications. As molecular carriers, their branched layered architectures display a high number of controlled terminal groups as well as cavities for physical entrapment. Only in recent years have dendrimers comprised of heterogeneous segments (Janus dendrimers) been designed for biomedical application. 

The objective of this research is to design and synthesize a series of supramolecular amphiphilic Janus dendrimers comprised of biocompatible polymeric segments that can self-assemble into narrow size distributed nanoparticles. These dendrimers are designed to combat issues often faced in nanomedicine such as biocompatibility and tunable transport properties. Our work will cast a new light on the design of supramolecular systems for biomedical applications.

Davita Watkins

A native of Memphis, Tennessee, Davita L. Watkins obtained her B.S. in Chemistry and Anthropology from Vanderbilt University in Nashville, Tennessee. After working briefly for a bioanalytical company, she received a Ph.D. in Chemistry from the University of Memphis under the tutelage of Dr. Tomoko Fujiwara. As a doctoral candidate, she developed and established multi-step synthetic methods for a series of stimuli-responsive materials. In 2012, she accepted a postdoctoral position at the University of Florida in Gainesville, Florida, with Dr. Ronald K. Castellano, where she developed novel self-assembling organic materials for photovoltaic applications. In 2014, she began her independent academic career at the University of Mississippi, focusing on design guidelines towards functional materials with tunable properties through molecular self-assembly. Her research strategies have afforded materials with applications that range from solar-harvesting supramolecular polymers to nanosized diagnostic agents. Dr. Watkins is the recipient of several awards, including the Oak Ridge Associated Universities Ralph E. Powe Award, a National Science Foundation CAREER Award, a Polymeric Materials: Science and Engineering American Chemical Society Young Investigator Award and the Lloyd N. Ferguson Young Scientist Award. She has been named an International Union of Pure and Applied Chemistry Young Observer (2021) and Emerging Investigator (2018) by the Journal of Materials Chemistry C. Alongside her research efforts, Dr. Watkins is an active voice for initiatives to increase minorities and women in STEM.

LaShanda Korley

Professor LaShanda Korley
Department of Materials Science and Engineering
University of Delaware
Host: Professor Tim Lodge

Abstract

Bio-Inspired and Sustainable Design: Towards Functional Polymeric Materials

Materials that are found in Nature display a wide range of properties, including responsiveness to the environment, signal transmission, and the ability to adapt to support life. Learning from Nature, biomimetic principles can be powerful tools in designing, developing and accessing the next generation of synthetic materials and systems. Using a bio-inspired framework, I will highlight several molecular design strategies utilizing cues from natural systems to demonstrate several examples of gel and network materials that exhibit mechanical tunability, responsive behavior, and hierarchical architectures. 

Additionally, I will highlight pathways that enable materials sustainability via a life cycle management framework focusing on biomass building blocks. Alternative synthetic approaches are critical for the utilization of biomass building blocks in the development of robust polymeric materials with exceptional mechanical function and thermal properties. Lignocellulosic biomass, particularly the lignin fraction, is an attractive source of diverse, abundant, and inexpensive precursors for macromolecular design. I will discuss convergent research efforts to develop performance-advantaged materials within a circular economy.

Research

Prof. LaShanda T. J. Korley is a Distinguished Professor in the Departments of Materials Science & Engineering and Chemical & Biomolecular Engineering at the University of Delaware (UD). Previously, she held the Climo Associate Professorship of Macromolecular Science and Engineering at Case Western Reserve University, where she started her independent career in 2007. Taking inspiration from nature, her research program involves understanding the design rules employed by nature and applying these strategies to the development of mechanically-enhanced and tunable materials. Prof. Korley is the Director of the recently awarded Energy Frontier Research Center – Center for Plastics Innovation (CPI) funded by the Department of Energy and also the Co-Director of the recently announced Materials Research Science and Center – UD Center for Hybrid, Active, and Responsive Materials (UD CHARM). She is also the Principal Investigator for the National Science Foundation Partnerships for International Research and Education (PIRE): Bio-inspired Materials and Systems and the Associate Director of the Center for Research in Soft matter & Polymers (CRiSP) at the University of Delaware.

LaShanda Korley

She received a B.S. in both Chemistry & Engineering from Clark Atlanta University as well as a B.S. in Chemical Engineering from the Georgia Institute of Technology in 1999. Prof. Korley completed her doctoral studies at MIT in Chemical Engineering and the Program in Polymer Science and Technology in 2005, and she was the recipient of the Provost’s Academic Diversity Postdoctoral Fellowship at Cornell University in 2005. She was named a DuPont Young Professor in 2011 and was selected for the National Academy of Engineering Frontiers of Engineering symposium. She was a Kavli Fellow of Japanese/American Frontiers of Science Symposium from 2012-16. Recently, Prof. Korley was elected as Fellow of the American Institute for Medical and Biological Engineering, and was awarded the National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) Lloyd N. Ferguson Young Scientist Award for Excellence in Research and the American Institute for Chemical Engineers (AIChE) Minority Affairs Committee Gerry Lessells Award. Her research focuses on bio-inspired polymeric materials, film and fiber manufacturing, plastics recycling and upcycling strategies, stimuli-responsive composites, peptide-polymer hybrids, fiber-reinforced hydrogels, and renewable materials derived from biomass.

Hope Flanagan

Abstract

Introduction to Indigenous Cultural Issues

This seminar will focus on an introduction to indigenous cultural issues including the land-back movement, how the Ojibwe language can help us see science from new perspectives and expand our world views, followed by a discussion of DWH’s goals with seed keeping and food sovereignty in the Twin Cities.

Dream of Wild Health (DWH)

DWH is an intertribal independent nonprofit that serves the Native American community in the Twin Cities. Some of their initiatives include growing & rematriating Indigenous crops on their farm, and o er year-round youth programming that include education on traditional gardening, cooking and other leadership opportunities. They also run community supported agriculture called Indigenous Food Share that are similar to individually purchased CSAs. DWH also sells produce at two local farmers markets in the Twin Cities and provides produce to Native programs in the Twin Cities including the Gatherings Cafe and Owamni restaurant.

Professor Michelle Arkin

Departmental Seminar
Professor Michelle Arkin
UCSF
Host: Professor Bhagi-Damodaran

Abstract