Controlling the freezing process: a robotic device for rapidly freezing biological tissues with millisecond time...

Area of Science:

• Biophysics
• Cryobiology
• Robotics

Background:

• Accurate determination of cellular process kinetics requires rapid and standardized tissue freezing.
• Existing methods often lack the necessary time resolution or standardization for diverse sample types.

Purpose of the Study:

• To develop a robotic cryogenic device for high-resolution, millisecond-timescale freezing of biological tissues.
• To enable standardized freezing times for biological samples of varying initial thicknesses.

Main Methods:

• A robotic system with two liquid nitrogen-cooled hammers driven by linear servo-motors was designed.
• A rapid-drop chamber mechanism, controlled by a PC and solenoids, positions tissue samples for impact.
• Adjustable mechanical stops control the final compressed thickness of the frozen tissue.

Main Results:

• Freezing time was found to increase with the square of the final frozen tissue thickness.
• Compressing samples of different original thicknesses to a uniform final thickness resulted in similar freezing times.
• The device demonstrated the ability to vary final tissue thickness and standardize freezing duration.

Conclusions:

• The developed robotic cryogenic device achieves millisecond freezing resolution for biological tissues.
• The ability to adjust final thickness standardizes freezing times, overcoming limitations with diverse sample sizes.
• This technology facilitates accurate kinetic analysis of cellular processes in biological samples.