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Qian Chen, an assistant professor of materials science and engineering, will speak at noon Thursday, Oct. 8 as part of the Beckman Institute’s Director’s Seminar series. Chen will discuss “ ‘Cinematography’ at the Nanoscale, From Colloidal Crystallization to Protein Transformation.” Fall presentations will be presented online through Zoom; registration is required to access the lectures.
“ ‘Cinematography’ at the Nanoscale, From Colloidal Crystallization to Protein Transformation”
Chen will discuss her group’s recent progress on applying low-dose liquid-phase TEM to synthetic and biological colloidal systems. In the first system, they directly image the otherwise elusive crystallization pathways of nanosized colloids into superlattices, where the discreteness and multi-scale coupling effects complicate the free energy landscape and the application forms of the final superlattices. They find that there exist similarities to the prevalent model system of micron-sized colloids, such as a non-classical two-step crystallization pathway, and an agreement with the capillary wave theory. But there are also differences, in particular, a universal layer-by-layer growth mode that has been consistently observed for diverse nanoparticle shapes. Single particle tracking, trajectory analysis, and simulations combined unravel the energetic and kinetic features rendering this crystal growth mode possible and universal at the unexplored nanoscale, enabling advanced crystal engineering. In the second system, they sandwich and capture moving membrane proteins in their native lipid and liquid environment at nm resolution. The proteins exhibit real-time “fingering” fluctuations, which they attribute to dynamic rearrangement of lipid molecules wrapping the proteins. The conformational coordinates of protein transformation obtained from the real-space movies are used as inputs in our molecular dynamics simulations, to verify the driving force underpinning the function-relevant fluctuation dynamics. This platform invites an emergent theme of structural biophysics as they foresee.
Qian Chen is an assistant professor in the Materials Science and Engineering Department at the University of Illinois Urbana-Champaign. She earned her Ph.D. from the same department with Professor Steve Granick (2012) and did her postdoc with Professor Paul Alivisatos at UC Berkeley under a Miller Fellowship. She joined the faculty at U of I in 2015 and since then has received awards for her group's research, including Victor LaMer award in ACS (2015), Forbes 30 under 30 Science List (2016), Air Force Office of Scientific Research YIP award (2017), National Science Foundation CAREER award (2018), Sloan Research Fellow in Chemistry (2018), and Unilever award in ACS (2018). The research in her group focuses on the broad scheme of imaging, understanding and engineering active soft matter, including systems such as colloidal self-assembly, protein aggregation, advanced battery devices, and energy-efficient separation strategies.