An investigation of phase behavior and crystal nucleation kinetics in solutions of globular proteins

Nucleation and growth of low defect density structures remains a significant technological challenge. Indeed, when dealing with nanoparticles with chemically heterogeneous surfaces, locating crystallizing conditions remains an art rather than a science. Particular examples of these problems can be found in the crystallization of globular biological macromolecules. Recent progress has been made in locating conditions favorable for crystal growth based on characterizing the strength of particle interactions. The strength of particle interactions can be controlled using solution variables such as temperature, ionic strength, buffer type and additives. Under different solution conditions, crystals nucleate at greatly different rates. Decoupling the effects of solution variables on thermodynamic force and on the kinetics of crystal nucleation requires characterizing the strength of particle interactions, equilibrium phase behavior and measuring the rate of nucleation. In this work, protein solution second virial coefficient, B₂, solubility and liquid/liquid critical point are used to characterize phase behavior. Rates of nucleation are characterized using nucleation induction time measurements. This thesis presents a detailed investigation of the links between strength of interactions, equilibrium phase behavior and kinetics of crystal nucleation in solutions of globular proteins.