Uniform Droplets in a Microfluidic System Designed for Biopreservation

During freezing, in addition to physical damage to membrane, crystallization can cause fatal damage to cells by pushing mobile molecules and confine them in small bits of cell volume causing dramatic decrease in local ion concentration eventually result in poisoning of cell organelles. Vitrification of intracellular molecules can overcome cryopreservation problems caused by crystallization. In order to achieve vitrification tremendous rates of heat removal must be applied on cells around 10^6 C/s, which are currently not possible for biological materials. In this research we investigated a new method via microfluidic devices proposed by Dr. Mehmet Toner for pre-concentration of cells with CPAs while putting cells under a lot fewer mechanical and osmotic stresses than traditional methods. New method is based on trapping cells into aqueous droplets and controlling the CPA concentration in the droplet by adjusting temperature of the system. By conducting Finite Element Analysis calculations of the microfluidic system, we found that it is possible to pre-concentrate mammalian cells with CPA 10 times the initial CPA concentration under 3 minutes with the new BioMEMS based method.