Seminar Series

Upcoming Seminars Heading link
Join us for these upcoming seminars.
David McComb Heading link

David McComb
Director of the Center for Electron Microscopy and Analysis (CEMAS)
Ohio Research Scholar and Professor of Materials Science and Engineering
The Ohio State University
April 24, 2025 | 3:30 PM
Lecture Center D5 (UIC East Campus, Quad)
Title: Determining molecular functionality using electron energy-loss spectroscopy in the scanning transmission electron microscope.
Abstract: The need to characterize chemistry, structure and bonding with high spatial resolution has driven the exciting developments in electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) over the last two decades. This has been achieved with the development of high-performance electron monochromators, improved spectrometer electron optics and introduction of new detectors with a high detector quantum efficiency (DQE). This has culminated in achievement of an energy resolution of 4 meV (32 cm-1) or less on a few STEM-EELS instruments. This level of performance is opening new opportunities for the study of both electronic and vibrational excitations using high resolution EELS in the scanning transmission electron microscope (STEM). One of the most exciting, and challenging, research opportunities for high resolution STEM-EELS is to identify functional groups in organic/biological systems and determine their spatial distribution. In the first part of this seminar, I will discuss recent research results demonstrating the use of high-resolution STEM-EELS to identify functional groups in polymers and to use this to spatially map such groups at the dentin-enamel junction (DEJ) to gain insight into biomineralization mechanisms. In many “soft” materials the damage caused by the electron beam limits the data quality that can be achieved, even with the use of “smart” scanning algorithms and machine learning optimizations. The use of cryogenic sample cooling has been employed to dramatic success in the determination of structure of proteins and macromolecules by cryoEM. This requires cryo-transfer of flash frozen samples into the microscope, a capability that, until recently, was not available on STEM-EELS systems capable of ultimate energy resolution. I will report the development of a cryo-transfer system for the monochromated aberration corrected (MAC-) STEM at Oak Ridge national Laboratory (ORNL) and will show early results on the study of several macromolecular systems by vibrational spectroscopy using cryo-STEM-EELS.
RSVP for McComb Seminar Heading link
Past Seminars Heading link
Here are some of the great speakers we’ve hosted at IFRM.
Michelle Smeaton Heading link

Michelle Smeaton
Postdoctoral Researcher
National Renewable Energy Laboratory
January 15, 2025 | 3:00 PM
Science and Engineering South (SES) Room 238
Title: Investigations of nanoscale heterogeneity with atomic-resolution STEM.
Abstract: Highly localized structure measurements using scanning transmission electron microscopy (STEM) enable the exploration of new and distorted crystal structures stabilized on nanometer to micrometer length scales. STEM also allows for the study of heterogeneity and defects in such systems over length scales too small to resolve with x-ray scattering techniques. One area where this ability is particularly impactful is the study of non-stoichiometric compounds, where nanoscale inclusions of different phases can have significant effects on properties measured by bulk characterization methods. I will discuss the case of oxygen-deficient lanthanum nickelate (LaNiO3-d), in which nanoscale coexistence of d = 0.25 and 0.5 phases can give rise to electronic and magnetic phase transitions otherwise unexpected in LaNiO3. By combining phase mapping with 4D-STEM and atomic displacement mapping with direct atomic column fitting, I will elucidate the nanostructure of these domains and extract their associated lattice distortions from the parent LaNiO3 crystal structure. I will further discuss the impact of electron channeling on such atomic fitting analyses, which have become more common with the accessibility of aberration-corrected STEM instruments, and suggest strategies to avoid potential unwanted or unexpected effects thereof. Finally, I will share my ongoing efforts to map the high temperature spin transition in LaCoO3, which is a promising candidate for energy-efficient neuromorphic switching devices, using in-situ heating in the STEM. I will discuss my progress and challenges and end with an outlook for in-situ electrical biasing experiments conducted on working devices.
Lola Eniola-Adefeso Heading link

Lola Eniola-Adefeso
Dean, College of Engineering
University of Illinois Chicago
October 24, 2024
Title: Leveraging the Natural Cellular and Biomolecular Interactions in Blood for the Design of Targeted, Anti-Inflammatory Particle Therapeutics.
Abstract: Vascular-targeted particle therapeutics offer the possibility of increased drug effectiveness while minimizing side effects often associated with systemic drug administration. Factors that influence the likelihood of targeted particle therapeutics to reach the vascular wall are the ability to identify: 1) a disease-specific target, 2) the appropriate drug carrier type and geometry for efficient interaction with the vascular wall, and 3) a drug-carrier combination that allows for the desired release of the targeted therapeutics. Our work focuses on probing the role of particle geometry, material chemistry, and blood rheology/dynamics on the ability of vascular-targeted drug carriers to interact with the blood vessel wall – an important consideration that will control the effectiveness of drug targeting regardless of the targeted disease or delivered therapeutically. This presentation will highlight the carrier-blood cell interactions that affect drug carrier binding to the vascular wall and alter critical neutrophil functions in disease. The talk will present the material design parameters for optimal drug carriers’ design for active and passive use in treating acute lung injury and other inflammatory diseases.