Description:

Weekly guest and student speakers in the Department of Chemical and Biological Engineering.

Jennifer Linderman
University Michigan

Title: Computational perspectives on treating tuberculosis

Abstract: Approximately one third of the world’s population is infected with Mycobacterium tuberculosis, and in 2015 tuberculosis (TB) was responsible for 1.4 million deaths. Despite an arsenal of anti-TB antibiotics, effective treatment remains a challenge. Our approach to understanding the immune response to M. tuberculosis, protection, and treatment integrates data from multiple experimental approaches with a multi-scale computational analysis. I will describe work that addresses the questions: (1) What factors might explain why some individuals develop an active infection while others achieve latency? (2) Why do antibiotics sometimes fail, and how can we effectively explore the enormous ‘design space’ of possible antibiotic treatments? (3) What computational approaches can help bridge the gap between understanding the behavior of single lung lesions versus the entire individual? Our work adds to the understanding of mechanisms that influence TB and its treatment as well as identifies potential new therapeutic directions.  

Bio: Linderman is a Professor of Chemical Engineering and of Biomedical Engineering at the University of Michigan and a fellow of AIMBE. She is also Director of the University of Michigan ADVANCE Program, which focuses on faculty diversity and excellence. She received her PhD from the University of Pennsylvania and did her postdoctoral work at the University of Massachusetts. Her research interests include computational modeling, immunology, tuberculosis, cancer, signal transduction and receptor dynamics.

Description:

Vivek Sharma of UIC
Host: Wes Burghardt

Title:
Stretched Polymer Physics, Pinch-off Dynamics, Rheology and Printability of
Polymeric Complex Fluids

Abstract:
Liquid transfer and drop formation/deposition processes associated with printing, spraying, atomization and coating flows involve complex free-surface flows including the formation of columnar necks that undergo spontaneous capillary-driven instability, thinning and pinch-off. For simple (Newtonian and inelastic) fluids, a complex interplay of capillary, inertial and viscous stresses determines the nonlinear dynamics underlying finite-time singularity as well as self- similar capillary thinning and pinch-off dynamics. In rheologically complex fluids, extra elastic stresses as well as non-Newtonian shear and extensional viscosities dramatically alter the pinch- off dynamics. Stream-wise velocity gradients that arise within the thinning columnar neck create an extensional flow field, and many complex fluids exhibit a much larger resistance to elongational flows than Newtonian fluids with similar shear viscosity. Characterization of the response to both shear and extensional flows that influence dispensing and liquid transfer applications requires bespoke instrumentation not available, or easily replicated, in most laboratories. Here we show that dripping-onto-substrate (DoS) rheometry protocols that involve visualization and analysis of capillary-driven thinning and pinch-off dynamics of a columnar neck formed between a nozzle and a sessile drop can be used for measuring extensional viscosity and extensional relaxation time of polymeric complex fluids. We show that the DoS rheometry protocols we have developed enable the characterization of low viscosity printing inks and polymer solutions that are beyond the measurable range of commercially-available capillary break-up extensional rheometer (CaBER). We find that the extensional relaxation times of dilute and semi-dilute, unentangled polymers in good solvent exhibit much stronger concentration dependence than observed in shear rheology response or anticipated by blob models developed for relaxation of weakly perturbed chains in a good solvent. We investigate the role of charge by contrasting the pinch-off dynamics and the rheological response of weak and strong polyelectrolytes and characterizing the influence of the electrolyte concentration. We elucidate the influence of chemical structure on stretched polymer physics by contrasting the behavior of aqueous solutions of flexible polyethylene oxide (PEO) with solutions of semi-flexible hydroxyethyl cellulose (HEC). We show that flexibility, extensibility and charge dramatically influence the extensional rheology response and the macromolecular relaxation dynamics. Finally, we elucidate how macromolecular stretching and orientation in response to strong extensional flows modifies the excluded volume and hydrodynamic interactions, affecting the terminal extensional viscosity response as well as polymer relaxation dynamics, and consequently, determine the filament lifespan, the processing timescale, and processability for printing, coating, dispensing, and spraying applications.

Description:

Weekly guest and student speakers in the Department of Chemical and Biological Engineering.

Description:

Julie Champion
Associate Profesor - Georgia Institute of Technology

Title:
Understanding and Controlling Protein Self-Assembly for Development of Therapeutic Materials

Abstract:
Proteins can provide therapeutic functions simply not possible with small molecule drugs, but their large size and folded structure present critical challenges in terms of delivery, stability and activity. We take advantage of protein size, structure and the ability to interact with other proteins, in order to create therapeutic protein materials via self-assembly routes not available for small molecules. The ability to control assembly of therapeutic proteins is essential to manipulating the final physical properties of the material, ensuring retention of protein activity, and directing the interactions between materials and cells.

In this presentation, I will describe the development, characterization and performance of two different functional protein assemblies, intracellular antibody Hex nanocarriers and globular protein vesicles. The Hex carriers seek to open up the intracellular space for antibodies as an approach to aim at “undruggable” intracellular protein targets. The vesicles, themselves made from functional proteins, aim to present protein and small molecule cargo for a variety of applications. In each case we applied a rational protein design strategy to enable self-assembly and have performed extensive characterization to understand the structures formed, their dynamics and stability, and how to tune the material properties for specific applications. These properties significantly affect how the protein assemblies interact with biological systems and the current status of application of these materials towards therapeutic targets will be shared.

Bio:
Julie Champion is an Associate Professor in the School of Chemical & Biomolecular Engineering at Georgia Institute of Technology and a member of the Institute for Bioengineering and Biosciences and the Bioengineering Program. She earned her B.S.E. in Chemical Engineering from the University of Michigan. Dr. Champion completed her Ph.D. in Chemical Engineering at the University of California Santa Barbara as a National Science Foundation graduate fellow under the advisement of Dr. Samir Mitragotri. She was a National Institutes of Health postdoctoral fellow at the California Institute of Technology in the lab of Dr. David Tirrell. Professor Champion’s current research focuses on design and self-assembly of functional materials made from engineered proteins for applications in immunology, cancer, and more recently, biocatalysis. Dr. Champion has received a BRIGE award from the National Science Foundation, the Georgia Tech Women in Engineering Faculty Award for Excellence in Teaching, and the Georgia Tech BioEngineering Program Outstanding Advisor Award.

Description:

Weekly guest and student speakers in the Department of Chemical and Biological Engineering.