CAREER: Harnessing liquid-liquid crystal phase separation in solutions of rod-shaped particles for the design of functional materials

About This Grant

Cells in the human body contain many small compartments with distinct chemical environments. Many biomolecules are localized within the specific compartments that enable them to carry out biochemical reactions that maintain cellular functions. It is now understood that compartmentalization has an important role in human health, including cell signaling and disease. This project will focus on how the shape of a biomolecule may affect its compartmentalization. Experiments will reveal the impact of biomolecule shape – spherical compared with rod-like, for example - on the formation, stability, and composition of these compartments. Results will help identify the fundamentals underlying this crucial biological process that can be helpful in designing bio-based devices, such as sensors that detect DNA and proteins. The insights gained from the project will be used to create experimental modules on “Soft Materials in Everyday Life” for hands-on training of high school students. This project will address the fundamental question of “how liquid-liquid separation of particles is affected by particle shape”? Experiments will study a liquid-liquid crystal phase separation when the participating polymers/particles have a rod-like shape. Orientation-dependent interactions of the rod-like particles will be studied within the framework of associative and depletion-mediated processes. Experiments will elucidate the phenomenology behind electrostatics-driven liquid-liquid crystal phase separation leading to the formation of liquid crystalline coacervates. Additional experiments will focus on liquid crystal ordering at the surface of a coacervate droplet. Liquid crystal ordering will be harnessed for developing sensors that report the presence of proteins. Experiments will also uncover fundamentals of depletion-mediated liquid-liquid crystal phase separation in suspensions of binary rod-rod particles. The experiments will map the phase behavior of water-based liquid crystals in the presence of DNA having different base pair lengths. Additionally, the phase diagrams of the liquid crystals will be engineered such that live DNA amplification can be reported when the concentration of the depletant exceeds a critical threshold. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.