Scientists Examine First-of-its-Kind “Living” Nanomaterial

A new kind of electron microscopy permits scientists to analyze nanoscale tubular materials when they are “alive” and forming liquids—a first-of-its-kind in the field.

The new technique, known as variable temperature liquid-phase transmission electron microscopy (VT-LPTEM), was developed by multidisciplinary researchers at the University of Tennessee and Northwestern University, and allowed them to study these high-resolution dynamic, sensitive materials. Scientists used these details to better understand how nanomaterials grow, form, and develop.

Until now, we could only look at ‘dead,’ static materials. This new technique allows us to examine dynamics directly—something that could not be done before.

Nathan Gianneschi, Study Co-Lead and Professor, Department of Chemistry, Northwestern University

The study has been published online this week in the Journal of the American Chemical Society.

Gianneschi is the Jacob and Rosaline Cohn Professor of Chemistry in Weinberg College of Arts and Sciences, Northwestern University, associate director of the International Institute for Nanotechnology, and professor of materials science and engineering and biomedical engineering in the McCormick School of Engineering. He co-led the research with David Jenkins, associate professor of chemistry at the University of Tennessee, Knoxville.

After live-cell imaging became feasible in the early 20^th century, it transformed the field of biology. For the first time, researchers were able to observe living cells as they actively developed, migrated, and carried out important functions. Previously, scientists could only study dead and fixed cells. The leap in technology offered crucial insight into the behavior and nature of tissues and cells.

“We think LPTEM could do for nanoscience what live-cell light microscopy has done for biology,” said Gianneschi.

LPTEM permits scientists to mix components and carry out chemical reactions when observing them unfold under a transmission electron microscope.

We think LPTEM could do for nanoscience what live-cell imaging has done for biology.

Nathan Gianneschi, Study Co-Lead and Professor, Department of Chemistry, Northwestern University

In this research, Gianneschi, Jenkins and their colleagues investigated metal-organic nanotubes (MONTs), which are a subclass of metal-organic frameworks.

MONTs have shown a great potential use of nanowires in miniature electronic devices, semiconductors, nanoscale lasers, and sensors for detecting virus particles and cancer biomarkers. However, MONTs are hardly analyzed because the key to explain their potential depends on the understanding of their formation.

For the first time, the team at Northwestern University and the University of Tennessee noted the formation of MONTs with LPTEM and recorded the initial measurements of finite bundles of MONTs on the nanometer scale.

The research titled “Elucidating the growth of metal-organic nanotubes combining isorecticular synthesis with liquid-cell transmission electron microscopy” was financially supported by the National Science Foundation (award numbers ECCS-1542205 and DMR-1720139) and the Army Research Office (W911NF-18-1-0359).

The research was carried out in association with Gianneschi’s laboratory, which has proficiency in transmission electron microscopy, and Jenkins’s laboratory, which has proficiency in metal-organic nanotubes. Karthikeyan Gnanasekaran, Northwestern postdoctoral fellow, and Kristina Vailonis, University of Tennessee graduate student, served as the co-first authors of the study. Gianneschi is also a member of the Simpson Querrey Institute, Chemistry of Life Processes Institute, and the Robert H. Lurie Comprehensive Cancer Center at Northwestern University.