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Tanya Prozorov demonstrates working with biological samples using existing equipment. Prozorov is awaiting arrival of a new continuous flow liquid cell holder for the Lab’s transmission electron microscope that will allow her to study how magnetic nanocrystals, similar to those shown in the micrograph at the right, form.


Ames Laboratory scientist Tanya Prozorov is clearly enthusiastic when she talks about her research. She has trouble suppressing a smile as she excitedly details the project that will take her into uncharted territory.

This “expedition,” however, won’t take her and her yet-to-be-named research team to some exotic location. The new territory will be trying to watch biomagnetic crystals as they form using a custom-built sample holder for the Lab’s Technai transmission electron microscope. The work is being funded through a five-year, $2.5 million Department of Energy Early Career Award which Prozorov was awarded earlier this year.

Prozorov’s project, “Real-Time Studies of Nucleation, Growth and Development of Ferromagnetism in Individual Protein-Templated Magnetic Nanocrystals,” will focus on isolating individual biotemplated magnetic nanocrystals in an attempt to identify the mechanisms that control how these crystals form and develop their magnetic properties.

“With the majority of current characterization techniques, what you see is a static picture – a snapshot – of multiple nanocrystals,” Prozorov says. “These particles interact with each other, and it masks what’s really taking place.”

“Also, we normally observe them after they’ve formed,” she continues. “I want to try to isolate and view individual particles as they grow, in situ, to see what’s taking place. There’s nothing like actually seeing it to help you understand how they form. And understanding this will ultimately allow controlling the emergent magnetism.”

Building her expertise in specialized electron microscopy techniques is the first step, according to Prozorov, who describes herself as “just a materials chemist with a passion for electron microscopy.” For example, to study growing, bio-inspired samples requires that they be suspended in liquid, which presents a particular set of problems.

“It takes a specialized piece of equipment – a continuous flow liquid cell TEM (transmission electron microscope) holder – to be able to view the nanocrystal formation in liquid,” she says. Additionally, a “molecular printer” called a Nano Enabler is necessary to dispense the requisite nano-scale quantities of the biological templating material. Cryo-electron microscopy techniques will be used to literally freeze the particles in various stages of development so their images can be captured.

Prozorov will collaborate with Ames Lab scientist and electron microscopy expert Matt Kramer and his group. She’ll also continue to work closely with faculty scientist Surya Mallapragada, whose research group focuses on the bio-inspired magnetic nanocrystals that led to Prozorov’s proposal for the Early Career Award program.

~ by Kerry Gibson