Miniaturised microfluidic technology to probe the fundamentals of heterogeneous ice nucleation

The heterogeneous nucleation of ice is a critical process in fields as diverse as cryopreservation through to atmospheric cloud formation, yet it is extremely poorly understood. There are a range of materials which nucleate ice including minerals such as feldspars through to macromolecules from biogenic materials such as pollen or fungus. We can quantify how efficiently these materials nucleate ice, but we do not understand how these materials nucleate ice and we have no predictive capacity for determining how well any given material will trigger nucleation. This hampers our ability to select nucleants for use in the control of ice nucleation in cryopreservation applications and restricts our predictive understanding of ice nucleation by atmospheric aerosol particles.
In this project, the postgraduate researcher will focus on improving our basic knowledge of ice nucleation through novel laboratory experimentation utilising the unique equipment and resources which have been developed in the Leeds Ice Nucleation Group. In particular, the candidate will use and further develop our new microfluidics device for quantifying ice nucleation. The researcher will also be uniquely positioned to exploit their discoveries in the fields of: nucleation of ice in clouds and the control of the formation of ice in biological samples during cryopreservation. Ice nucleation in clouds helps define life on Earth since clouds play a central role in our planet’s climate and its hydrological cycle, while the control of ice nucleation is a key limitation in a range of areas, such as the supply of cells for the high throughput toxicology screening of pharmaceutical products.
The successful candidate will capitalise on our unique position where we use fundamental knowledge of ice formation in the atmosphere to underpin the control of ice formation in cryopreservation (and vice versa). In doing so, the postgraduate researcher will contribute to a better prediction of climate change, one of humanities greatest challenges, as well as improving the storage of biological specimens which will lead to life saving new drugs and treatments. Hence, this PhD will equip the candidate for a future in a range of careers.
Objectives
This project will be based around making use of and improving our new microfluidics device with the objective of improving our fundamental understanding of why some materials nucleate ice and why. This may involve the following:
1. Learn to use and apply our current microfluidic device for quantifying ice nucleation in flowing droplets.
2. Improve the design with the object of creating an instrument to measure ice nucleating particles in the atmosphere on a semi-autonomous basis. This will involve coupling the microfluidics device to an aerosol particle sampler and possibly replacing the bulky high speed microscope set-up with a much more compact laser scattering system. This will also involve testing the instrument against other standard techniques.
3. Design a chip to explore different time-scales of nucleation in order to characterize the stochastic vs deterministic properties of nucleation.
4. Couple the microfluidics device to a size exclusion chromatography column to identify and isolate specific ice nucleating macromolecules.
5. Use a new frozen vs. unfrozen flow separation device to separate ice nucleating particles from inert particles in order to determine what makes these particles nucleate ice.
6. Potentially use the new knowledge of what makes an effective ice nucleation site in order to artificially create ice nucleation sites which might be used for the control of ice nucleation in applications such as cryopreservation. This would be an excellent opportunity to interact with our partner cryopreservation company.
7. Potentially take part in a field campaign. While this project is laboratory focused, there will be opportunities to take part in field campaigns around the world where we study ice nucleation. In past campaigns we have travelled to the high Arctic, Barbados and Iceland, amongst other places. We also work on the UK research aircraft (FAAM) and research ships.