A numerical study on distributions during cryoprotectant loading caused by laminar flow in a microchannel

Area of Science:

• Biotechnology
• Biophysics
• Chemical Engineering

Background:

• Cryopreservation is crucial for long-term cell storage.
• Microfluidic devices offer precise control for cell processing.
• Efficient cryoprotective agent (CPA) loading is vital for cell viability.

Purpose of the Study:

• To computationally investigate CPA loading into cells using microfluidics.
• To analyze the impact of flow dynamics and cell migration on CPA transport.
• To identify parameters governing successful CPA loading for improved cryopreservation.

Main Methods:

• Computational fluid dynamics (CFD) simulations of flow and concentration fields.
• Lagrangian particle tracking of cells, accounting for the Segre-Sildinberg effect.
• Numerical solution of Kedem-Katchalsky equations for passive solute transport.

Main Results:

• A governing parameter α (ratio of membrane transport to residence time) was identified.
• Complete CPA loading (within 5% of target) achieved for α values around 1.
• Incomplete loading and concentration distribution observed for lower α values; negligible loading for α > 2.

Conclusions:

• Spatially varying concentration fields significantly impact CPA transport.
• Optimizing α through microfluidic design can ensure consistent CPA loading.
• This study provides a basis for developing enhanced microfluidic cryopreservation protocols.