Dr. Robert Szoszkiewicz

Kansas State University, Department of Physics

Biological and Soft-Matter Physics in the Szosz-lab, KSU

102 Cardwell Hall

September 17, 2013

4:30 p.m.

In this colloquium, I will overview our research activities in biological and soft-matter physics. Within our biological physics thrust, we measure physiologically relevant pN forces exerted by a tip of an atomic force microscopy (AFM) on a biomolecule. The last 15 years have witnessed an explosion of interest in such measurements fueled by: 1) new possibilities to advance our understanding of protein folding, 2) possibilities to elucidate molecular mechanisms of various cellular processes and diseases, and 3) efforts to understand the nanomechanical properties of proteins, polysaccharides and DNAs in order to design biomimetic and/or mechanically functional materials. I will concentrate on our efforts in elucidating initial folding events in a simple model protein from changes of molecular stiffness and dissipation factors. Using such measurements, we expect to provide basic understanding of early folding events in simple proteins and polypeptides. I will also show how mechanical force can influence rates and mechanisms of an enzymatic cleavage of a single disulfide bond. Within our non-biological, soft-matter physics thrust, we use hot-tip AFM methods to manipulate arbitrary polymer surfaces. I will present our recent understanding of heat induced nano-abrasive wear in amorphous polymers and copolymers. Finally, I will mention future directions and extensions of our research.