Micropipette aspiration as a tool for single-particle X-ray imaging and diffraction

Area of Science:

• X-ray science
• Nanotechnology
• Biophysics

Background:

• Studying single particles in aqueous environments using X-rays presents significant challenges.
• Existing methods often struggle with sample stability and precise manipulation in liquids.

Purpose of the Study:

• To develop and demonstrate a new sample environment for single-particle X-ray experiments in aqueous solutions.
• To enable manipulation and probing of individual particles within a stable liquid droplet.

Main Methods:

• A droplet-based system utilizing a patterned hydrophobic-hydrophilic substrate for droplet stabilization.
• Mineral oil overlay to prevent evaporation and minimize background.
• Micropipette manipulation and holographic X-ray imaging for observation and control.
• Controlled pressure differences for aspiration and force generation.

Main Results:

• Successful stabilization and manipulation of single particles within aqueous droplets.
• Demonstration of micropipette insertion, steering, and particle interaction.
• Holographic X-ray imaging effectively monitored the system, including pipettes, droplet surface, and particles.
• First experimental results obtained at synchrotron radiation facilities with nano-focused beams.

Conclusions:

• The developed sample environment is effective for single-particle X-ray experiments in aqueous solutions.
• The system shows promise for future coherent imaging and diffraction studies using synchrotron radiation and X-ray free-electron lasers.