SEMINAR 2024
Liquid Phase TEM for Hydrogel Structure Elucidation and Property Prediction
| Speaker | Prof Nathan C. Gianneschi, Northwestern University |
| Date/Time | Monday, 13 May, 11AM |
| Location | Conference room: S11-02-07 |
| Host | A/Prof Utkur Mirziyodovich Mirsaidov |
Abstract
Organic, soft materials with nanoscale structures inherent to their solvated state, such as emulsions, hydrogels, and thermally responsive materials, provide fertile ground for investigation via direct imaging using liquid phase transmission electron microscopy (LPTEM). With key advances having been made in the past decade, including improved sample preparation protocols, image capture technologies, and image analysis, LPTEM has gained in utility to the point where we are able to investigate materials that are otherwise difficult to directly image by other methods with nanoscale resolution. This workflow consists of (1) modelling electron beam-solvent interactions, (2) studying electron beam-sample interactions via LCTEM coupled with post-mortem analysis, (3) construction of “damage plots” displaying sample integrity under varied imaging and sample conditions, (4) optimized LCTEM imaging, (5) image processing, and (6) correlative analysis via X-ray or light scattering. Herein, we employ this workflow to examine hydrogel formation, dynamics and assembly in the solvated state. The insight gained has provided an exciting window into these materials that eludes cryogenic TEM, which is necessarily disruptive of these structures. We present our efforts in this space, and in the correlative methods used to verify, or support the structural information found. This includes the use of LPTEM to define gel parameters including persistence length and mesh sizes, which has led to the prediction of properties in thermally responsive gels.
Biography
Nathan C. Gianneschi received his B.Sc(Hons) at the University of Adelaide, Australia in 1999 under Louis Rendina. In 2005 he completed his Ph.D at Northwestern University, with Chad Mirkin. Following a Dow Chemical postdoctoral fellowship at The Scripps Research Institute with Reza Ghadiri, in 2008 he began his independent career at the University of California, San Diego where, until June 2017, he was Teddy Traylor Scholar and Professor of Chemistry & Biochemistry, NanoEngineering and Materials Science & Engineering. In July of 2017, Gianneschi moved his research group to Northwestern University where he is currently Jacob & Rosaline Cohn Professor of Chemistry, Materials Science & Engineering, and Biomedical Engineering. The Gianneschi group takes an interdisciplinary approach to nanomaterials research with a focus on multifunctional materials with interests that include biomedical applications, programmed interactions with biomolecules and cells, and basic research into nanoscale materials design, synthesis and characterization. For this work he has been awarded the NIH Director’s New Innovator Award, the NIH Director’s Transformative Research Award and the White House’s highest honor for young scientists and engineers with a Presidential Early Career Award for Scientists and Engineers. Prof. Gianneschi was awarded a Dreyfus Foundation Fellowship, is a Kavli Fellow of the National Academy of Sciences, a Fellow of the Royal Society of Chemistry, and is an Alfred P. Sloan Foundation Fellow.