Two graduate students will present their research at the first Beckman Institute Graduate Student Seminar of the fall 2022 semester: Kelly M. Chang, materials science and engineering; and Defne Gorgun Ozgulbas, Center for Biophysics and Quantitative Biology.

The hybrid seminar will take place at noon on Wednesday, Sept. 7 in 1005 Beckman and on Zoom. Lunch will be provided to in-person attendees. 

Register in advance to attend.

Improved durability of a high-Tg and impact-resistant thermoset in low-Earth orbit

Kelly M. Chang, materials science and engineering

Kelly M. Chang, materials science and engineering

Polymers degrade rapidly in low-Earth orbit due to high vacuum, extreme thermal cycling, atomic oxygen, and high-velocity micro-debris. These conditions lead to two main failure mechanisms: atomic oxygen-induced erosion and high-velocity impact damage. In this work, we investigate the qualifications of polydicyclopentadiene, or pDCPD, for space applications by characterizing its erosion yield and impact damage after a long-term LEO exposure aboard the International Space Station. Results suggest that pDCPD behaves similarly to epoxy in erosion resistance but outperforms epoxy in impact resistance. We also show that the incorporation of SiO2 nanoparticles can reduce atomic oxygen etch depth and dampen the reduction in mechanical properties. Lastly, we show that the atomic oxygen-resistance of pDCPD can be improved substantially by introducing a high-Tg crosslinker or through the incorporation of SiO2 nanoparticles.

Kelly M. Chang is a senior Ph.D. student in materials science and engineering. She is a member of Beckman's Autonomous Materials Systems Group working under Nancy Sottos. Her presentation highlights a highly collaborative effort between the Chasiotis group in the Department of Aerospace Engineering and the Dlott group in the Department of Chemistry.

Characterizing neutralizing mechanism of membrane-bound antibodies against influenza virus

Defne Gorgun Ozgulbas, Center for Biophysics and Quantitative Biology Defne Gorgun Ozgulbas, Center for Biophysics and Quantitative Biology

Influenza poses a major health issue globally. Characterized by annual epidemics with mild to severe symptoms and even a significant number of deaths, the virus has historically resulted in substantial economic and societal issues in the world. Neutralizing antibodies that target the hemagglutinin, or HA, protein in influenza virus provide considerable protection against the infection. While many specific antibodies bind to membrane-distal sites on HA, novel cross-reactive anti-HA antibodies have been recently discovered that bind to the highly conserved membrane-proximal stem of HA and potentially the viral membrane. Here, for the first time, we developed a high-resolution structural model of full-length, antibody-bound HA in a native membrane to characterize key interactions that govern the binding affinity between the antibody and the viral membrane. We have characterized the functional residues of the antibody that interact with and bind to the membrane using atomic-resolution molecular dynamics and enhanced sampling techniques to identify the number of antibodies that bind to HA. Using the developed model, we identify antibody residues that interact with the viral membrane and will evaluate their importance in virus neutralization by mutagenesis experiments. Given the rapid evolution of the influenza virus, the developed model provides a framework for the rational design and development of more effective therapeutic antibodies.

Defne Gorgun Ozgulbas is a 2022 Beckman Institute Graduate Fellow in the Center for Biophysics and Quantitative Biology. At Beckman, she conducts research in the Theoretical and Computational Biophysics Group, in the Tajkhorshid Lab. She is a fifth-year graduate assistant interested in studying biomolecular systems using equilibrium and nonequilibrium molecular dynamics simulations as well as enhanced sampling techniques. She received a Beckman Institute Graduate Fellowship for her work in characterization neutralizing activity of membrane-bound antibodies against influenza virus, advised by Emad Tajkhorshid and Nicholas C. Wu. In 2021, she worked as a research intern at the Argonne National Laboratory in the Ramanathan Lab; the lab's contributions to COVID-19 research were selected as a finalist for the ACM Gordon Bell Special Prize for High Performance Computing.

Learn more about Beckman's Graduate Student Seminar Series.

Read Q&As with student researchers on Beckman's Student Researcher Spotlight page.