Polymer-Protein Interactions: Stability, Adsorption, and Practical Insights
I will present new research that addresses the major challenge of identifying material properties that alter bio-macromolecule folding stability abiotic environments. How proteins interact with materials impacts a wide range of applications, from drug delivery to ship paints. A major goal of our work is to identify the molecular scale properties of materials that alter protein stability and function.
Recent studies of protein interactions with zwitterionic polymers and with temperature responsive poly(N-isopropyl acrylamide) (pNIPAM) challenge widespread views of polymers long thought to be protein compatible and non fouling (protein resistant). Fluorescence measurements of polymer/protein interactions produced surprising results. Despite a common view that poly zwitterions such as poly(sulfobetaine) (pSB) are ‘super low fouling’, soluble pSB binds and destabilizes proteins in solution. Proteins also adsorb on pSB thin films, and the non monotonic dependence on polymer coverage hints at the underlying adsorption mechanism.
Proteins similarly adsorb on pNIPAM, above the lower critical solution temperature where the chains are ‘sticky’ to proteins. Recent work with Martin Gruebele (Chemistry, U of Illinois) extended a fluorescence based approach, to quantify the impact of the polymer micro environments on protein stability, at submicron spatial resolution and millisecond time resolution. Surprising findings reveal that pNIPAM stabilizes adsorbed protein above the LCST. These results reveal unexpected ways that polymers perturb proteins and open up new avenues for identifying material properties that preserve or shut down protein function.
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Professor
Deborah Leckband is Professor of Chemical and Biomolecular Engineering and Chemistry at the University of Illinois at Urbana-Champaign. She is recognized internationally for pathbreaking research that identified interfacial forces and molecular mechanisms that control protein adsorption and function at both biological and abiotic interfaces. Professor Leckband is a pioneer in the use of molecular force probes to study proteins at interfaces, and has made major discoveries of the impact of interfacial forces on protein adsorption, recognition, and function. Her studies of the mechanical properties of cell surface adhesion proteins also uncovered novel ways that protein machines at cell surfaces transduce mechanical cues to regulate cell and tissue functions. Professor Leckband earned her BS and PhDs in Chemistry at Humboldt State University and Cornell, respectively, and was a postdoc with Robert Langer (MIT) and then with Jacob Israelachvili (UCSB). She is an Editor of Colloids and Surfaces B: Biointerfaces and has held positions in the American Chemical Society Colloids Division and the Biomedical Engineering Society. She has also served on several national and international advisory boards.
