The development of reliable genetic repositories is challenging. Effective cryopreservation calls for the use of industrial-scale programmable freezers that are costly and essentially unobtainable for institutions with limited resources. The Aquatic Germplasm and Genetic Resources Center here at Louisiana State University has addressed these challenges in the past with various versions of their open hardware 3D printed apparatus to make cryopreservation cheaper and more accessible. Among these include the Positional Cooling Platform Device (CryoKit), designed to float on liquid nitrogen and achieve various cooling rates (Figure 1). The issue being faced now is that devices such as the CryoKit can have very unpredictable cooling rates. The current solution to this is using a range of thicknesses of Styrofoam on the underside of the kit that helps the genetic samples achieve different cooling rates, but there is a considerable margin of error that can be observed in these rates because of the proximity the kit needs to be to the liquid nitrogen.
The goal now is to broaden the cooling rates that the CryoKit can achieve and make these cooling rates more predictable and consistent. To achieve this, a sort of lift system could be constructed that allows for a gradual descent into the nitrogen container. Additionally, the system could be entirely autonomous, utilizing microcontrollers, precision servos, and temperature sensors to control the rate of descent as well as ascend in the case the apparatus is cooling too quickly. Finally, a low-power aquatic air pump designed for home fish tanks with pneumatic tubing and an air stone could be used to percolate the liquid nitrogen in the container (Figure 2), raising vapors and increasing the temperature gradient within the enclosure.
The AGGRC has already created and tested a precision time-temperature sensor (coined as the Turtle) that could handle the immediate temperature data necessary for the lift. The aquatic motor and air stone used for percolating the nitrogen has also already been tested and shown to increase the temperature gradient drastically. These materials as well as the additional motors and microcontrollers are all easily accessible and cost-effective, increasing the price of the CryoKit’s implementation slightly, but still being orders of magnitude more achievable than the costly freezers previously discussed. Additionally, all the code and wiring schematics for this project would be published, allowing anyone to recreate it. The aim here is to create a system that can intelligently and automatically handle the cooling necessary for cryopreservation similarly to an industrial freezer, taking the strain away from the institutions using this setup as a preservation alternative. Of course, this setup would be an add-on to the existing solutions that have been published, entirely compatible and dynamic. This project is currently referred to as the Autonomous Positional Cooling Platform Device (CyroLift).