A Single-Entity Method for Actively Controlled Nucleation and High-Quality Protein Crystal Synthesis

Area of Science:

• Materials Science
• Biophysics
• Chemical Engineering

Background:

• Nucleation and crystal growth are fundamental processes across various scientific disciplines, yet controlling them remains a significant challenge.
• Current methods for biomacromolecule crystallization struggle to consistently produce high-quality crystals for structural analysis or tailored material properties.

Purpose of the Study:

• To establish a deterministic method for controlled single crystal nucleation and growth.
• To enable real-time monitoring and active control over crystal quality and habit.
• To demonstrate the method's potential for applications in fundamental research and materials development.

Main Methods:

• Utilizing a single nanopipette to confine supersaturation at the sample-precipitant interface.
• Employing electrokinetic ion transport, driven by an external potential waveform, to control matter exchange and supersaturation.
• Detecting nucleation and growth by monitoring disruptions in the nanotip-limited ionic current.

Main Results:

• Successfully achieved controlled nucleation and growth of single protein crystals (lysozyme) in real time.
• Demonstrated active control over crystal quality, with synthesized crystals achieving true atomic resolution up to 1.2 Å.
• Showcased the ability to tune crystal habits by adjusting ion flux during growth.

Conclusions:

• The developed electrokinetic nano-transport method provides unprecedented control over single crystal nucleation and growth.
• This technique offers a pathway to consistently obtain high-resolution diffraction data and engineer material properties.
• The underlying principles are generalizable to a wide range of materials systems beyond proteins.