Nanofluidic chips for cryo-EM structure determination from picoliter sample volumes

Area of Science:

• Structural biology
• Biophysics
• Materials science

Background:

• Cryogenic electron microscopy (cryo-EM) is vital for determining biological macromolecule structures.
• Inconsistent sample ice thickness hinders high-resolution imaging and limits cryo-EM throughput.
• The air-water interface can negatively impact sample integrity during preparation.

Purpose of the Study:

• To develop a novel sample support for cryo-EM specimen preparation.
• To address the challenge of achieving uniform ice thickness in cryo-EM samples.
• To enhance the reproducibility and efficiency of cryo-EM workflows.

Main Methods:

• Utilized a nanofluidic sample support with a defined geometry.
• Employed picoliter sample volumes within electron-transparent nanochannels.
• Tested the method with three standard protein specimens for structure determination.

Main Results:

• Achieved reproducible sample ice thickness using the nanofluidic device.
• Eliminated the destructive air-water interface during sample preparation.
• Demonstrated high-resolution structure determination from the prepared specimens.

Conclusions:

• Nanofluidic sample supports offer a reproducible method for cryo-EM specimen preparation.
• This technology has the potential to automate cryo-EM workflows.
• Enables new cryo-EM applications like time-resolved imaging and high-throughput screening.