Research Group(s)

• Biorefinery Engineering
• Molecular Systems and Biomaterials

Robin Curtis joined the department in 2003.  Previously, he completed his PhD in 2000 at the University of California at Berkeley under the supervision of John Prausnitz and Harvey Blanch.  Afterwards, he held post-doctoral positions at the University of California at Los Angeles and at Rive University in Houston under the supervision of Michael Deem. 

The research focus in the Curtis group is on determining protein-protein and protein-solvent interactions and linking them to solution properties such as protein aggregation kinetics, phase behavior (liquid-liquid phase separation, precipitation), and concentrated protein solution rheological properties. Experimental approaches cover static and dynamic light scattering, X-ray scattering, dilute and concentrated solution viscometry, and zeta-potential measurements. Simplified colloidal models are used for connecting interaction measurements to macroscopic phenomena. While most of the knowledge and understanding is directed towards research and development into biological medicines, we are also interested in the molecular mechanisms for maintaining protein homeostasis in cellular environments. Recent work has shown how electrostatic interactions can be manipulated and tuned either through rational mutagenesis of proteins or by using multivalent ionic excipients such as tri-polyphosphate (TPP) or adenosine tri-phosphate (ATP). ATP or TPP can be used to tune protein phase behaviour and suppress aggregation of proteins through a supercharging mechanism. A second area of research is probing the colloidal stability and interactions between partially-folded and unfolded proteins in solutions with chemical denaturants.  Along these lines, we showed that arginine to lysine mutations increase the unfolded state colloidal stability, which has been related to a reduction in aggregation propensity. Lastly, we are interested in the relationship between protein-protein interactions and the protein phase diagramme.  A recent study found that the critical point for liquid-liquid phase separation of three monoclonal antibodies occurs in a small window for the osmotic second virial coefficient irrespective of the precipitation conditions.