Effective Attraction between Like-Charged Particles and the Reentrant Condensation Behavior
03 Sep 2024
02.00 PM - 03.00 PM
Lecture Theatre 7 (NS1-02-03)
Alumni, Current Students
NTU MSE Seminar Hosted by Associate Professor Zhao Yang
Abstract
In a vacuum, negatively charged particles repel each other. However, we often observe the association of negatively charged proteins in biological systems. For example, G-actins associate with each other and make strong fibrils, although they are negatively charged. This means that effective attraction between the macroanions appears in a biological fluid, and the attraction is very strong.
This effective attraction only appears at a certain electrolyte concentration. For example, Zhang et al. have reported the reentrant condensation of negatively charged proteins in an electrolyte solution that contains multivalent cations. The attraction appears only at mM-order electrolyte concentration. This reentrant behavior on the effective interaction completely differs from the usual screened Coulomb interaction explained in textbooks.
Recently, experimental results related to this phenomenon have increased. Therefore, the effect is expected to be universal for charged polymers in an electrolyte solution containing multivalent cations. This effective interaction should be important to understand the construction of nanostructures in biological systems. In the present talk, I will explain the experimental results and discuss our theoretical results.
We have studied this phenomenon using statistical mechanics theory and molecular simulations. Our calculation results also demonstrate the effective attraction and reentrant behaviors when the Coulomb interaction is larger than the thermal energy. Based on our results, we explain the mechanism.
Biography
Associate Professor Ryo Akiyama
Ryo Akiyama is an associate professor in the Department of Chemistry at Kyushu University. He is also giving lectures at the Open University of Japan. He graduated from the Department of Nuclear Engineering at Hokkaido University and entered the Ph. D. course at the Department of Physics, Nagoya University. After obtaining his Ph. D., he worked as a post-doctoral fellow at the Institute for Molecular Science and Cornell University. He is interested in the application of statistical mechanics to chemical physics and biophysics, especially effective interactions between molecules in the liquid phase.
Associate Professor Ryo Akiyama
Kyushu University
Ryo Akiyama is an associate professor in the Department of Chemistry at Kyushu University. He is also giving lectures at the Open University of Japan. He graduated from the Department of Nuclear Engineering at Hokkaido University and entered the Ph. D. course at the Department of Physics, Nagoya University. After obtaining his Ph. D., he worked as a post-doctoral fellow at the Institute for Molecular Science and Cornell University. He is interested in the application of statistical mechanics to chemical physics and biophysics, especially effective interactions between molecules in the liquid phase.