高分子科学系列讲座256讲:Dr. Fajun ZHANG,Temporarily Arrested State in Protein Solutions Studied Using Ultra-Small Angle X-ray Scattering (USAXS)

文章来源:    发布时间:2017-08-09
报告题目:Temporarily Arrested State in Protein Solutions Studied Using Ultra-Small Angle X-ray Scattering (USAXS)(NO.PSLAB256-PS2017-13)
报 告 人:Dr. Fajun ZHANG
单  位:Universit?t Tübingen, Germany

 The interplay of liquid-liquid phase separation (LLPS) with the glass transition is a potential route to the formation of arrested states in colloidal and protein systems. However, the details regarding the kinetic transition from a complete LLPS to an arrested state are still not clear. In our work, we have employed the USAXS technique to study the kinetics of LLPS and arrested state in protein systems with a high temporal and spatial resolution. The two protein systems studied were bovine γ-globulin in the presence of PEG1k, and bovine serum albumin with YCl3. For both systems, the growth kinetics of the characteristic length (ξ) for shallow quenches was found to follow the classical coarsening kinetics with ξ~t1/3. For deep quenches, a fully arrested state was obtained. Interestingly, for intermediate quenches, we observed an unusual three-stage coarsening process. We consider the state of the system following this type of kinetics as a temporarily arrested state. We interpret the finding in the light of simulations and experimental results on colloidal systems. The temporary nature of the arrested state is most likely due to the asymmetric quench. In this case, the minority phase is the dilute phase, which can still coarsen through the glassy majority phase.

 Dr. Fajun ZHANG

11. 2005 - current: Project Leader (A.G. Prof. F. Schreiber), Permanent position since 09.2011. Institut für Angewandte Physik, Universit?t Tübingen

01.2015: Visiting Professor at Kyushu University, Japan

07.2014: Habilitation in Experimental Physics, Universit?t Tübingen

03.2004 - 10.2005: Alexander von Humboldt Fellow (A. G. Prof. B. Stühn). Institut für Festk?rperphysik, Technische Universit?t Darmstadt, Germany

03.2003 - 02.2004: Postdoctoral research assistant (Prof. A. M. Jonas) . Universite catholique de Louvain, Louvain-la-Neuve, Belgium

09.1997 - 10.2002: Doctoral candidate (Prof. T. He) . State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, China

09.1993 - 07.1997: Bachelor degree / under graduate. Department of Chemistry, Nankai University, Tianjin, China.