Unloading of cryoprotectants from cryoprotectant-loaded cells on a microfluidic platform

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cell Cryopreservation

Background:

• Cryoprotective agents are essential for preserving cells but must be removed post-thaw.
• Traditional cryoprotectant unloading methods can be inefficient and lead to cell loss.
• Microfluidic devices offer potential for controlled and efficient cell processing.

Purpose of the Study:

• To develop and evaluate a multistep dilution-filtration microdevice (MDFD) for cryoprotectant unloading.
• To investigate the impact of device design and operational parameters on unloading efficiency and cell viability.

Main Methods:

• Fabrication of an MDFD using PMMA stamps and PVDF membranes.
• Performance assessment of integrated mixers using fluorescence experiments.
• Evaluation of glycerin unloading from porcine red blood cells using the MDFD.
• Systematic study of cell density, cryoprotectant concentration, and membrane pore size effects.

Main Results:

• The MDFD achieved approximately 80% glycerin clearance (C_G) and 90% cell survival (S_C).
• Cell recovery rate (R_C) was limited to approximately 40%, primarily due to cell adhesion and loss through membrane pores.
• Increased membrane pore size enhanced C_G and S_C but reduced R_C.
• Low cryoprotectant concentration and high cell density significantly influenced C_G, S_C, and R_C.

Conclusions:

• The developed MDFD demonstrates significant potential for efficient cryoprotectant unloading from small cell samples.
• Optimization of membrane properties and device geometry is crucial to improve cell recovery.
• This microfluidic approach holds promise for applications in cryopreservation and cell-based therapies.