A microfluidic device for both on-chip dialysis protein crystallization and in situ X-ray diffraction

Area of Science:

• Biophysics
• Crystallography
• Microfluidics

Background:

• Protein crystallization is crucial for structure determination.
• Traditional methods can be time-consuming and require extensive optimization.
• In situ X-ray diffraction offers advantages but requires compatible sample environments.

Purpose of the Study:

• To develop a versatile microfluidic chip for on-chip protein crystallization and in situ X-ray diffraction.
• To optimize protein crystallization conditions within the microfluidic device.
• To assess the chip's compatibility with X-ray diffraction experiments.

Main Methods:

• Microfabrication of a chip with integrated regenerated cellulose dialysis membranes.
• On-chip optimization of crystallization via chemical composition and temperature control.
• In situ X-ray diffraction data collection and structure determination.

Main Results:

• Successful on-chip crystallization of three model proteins (lysozyme, IspE, insulin).
• Demonstrated compatibility with X-ray diffraction, showing low background scattering.
• Collected and merged diffraction data for complete structure determination.

Conclusions:

• The developed microfluidic chip provides a robust, inexpensive, and integrated solution for protein structure determination.
• It streamlines the process from crystal growth to diffraction data collection.
• Enables serial crystallography under dynamically controllable conditions.