UW-Madison innovations target bottlenecks in cryo-EM sample preparation

Researchers at the University of Wisconsin-Madison are advancing the field of cryogenic electron microscopy, or cryo-EM, by developing new methods for sample preparation that address existing challenges in the field. These innovations aim to improve the efficiency and accessibility of this powerful research tool.

Cryo-EM reveals the intricate architecture of proteins and other biomolecules, but conventional sample preparation is complex, costly and time-consuming. At present, proteins are prepared by being dissolved in water, applied to an EM grid - where most of the sample is blotted away - and then plunged into cryogen. This process can damage or denature delicate protein structures and reduce the structural heterogeneity of the sample.

"When the sample is frozen, the proteins might bunch, be damaged or lost, or not be oriented in the right way," says Jennifer Gottwald, WARF director of licensing. "The technical challenges and high cost of sample preparation continue to be a bottleneck."

One solution developed at UW-Madison is the addition of a reagent that forms a barrier at the air-water interface of the sample, preventing proteins from clumping or being damaged. This addition eliminates the need for additional processing or handling steps, allowing researchers to conserve time, money and sample material.

Another option utilizes a two-piece microfluidic flow cell for electron microscopy sample grid preparation. This enables live-cell imaging of biological materials after their growth and expansion in a liquid environment that mimics their native environment while preserving them for subsequent cryo-EM analysis.

An emerging line of innovations uses mass spectrometeters to facilitate sample preparation, including purification of proteins, improved vitrification techniques and facile EM grid transfer. These novel processes allow precise control over ice formation and sample orientation, improving image resolution. In addition to minimizing sample loss, these approaches reduce data acquisition time, an important consideration given the limited availability of cryo-EM instruments.

At UW-Madison, where several such instruments are housed at the UW-Madison Cryo-Electron Microscopy Research Center (CEMRC), researchers are uniquely positioned to lead cryo-EM innovation.

"The variety of approaches to improving sample preparation highlights the need for solutions, and UW-Madison is well-positioned to address this issue through a combination of expertise, resources and ambition," says Justin Anderson, WARF senior IP manager.

As the market for cryo-EM continues to grow, it is critical to develop solutions to existing limitations in sample preparation. By improving reliability, reducing cost and maximizing the quality of each image acquired, UW researchers are helping unlock the full potential of cryo-EM.

To learn more about these technologies and other UW research tools, contact Jennifer Gottwald at [email protected] .