Regensburg 2022 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Modeling and Simulation of Soft Matter (joint session CPP/DY)

CPP 9.6: Talk

Monday, September 5, 2022, 16:15–16:30, H39

Modulating internal transition kinetics of responsive macromolecules by collective crowding — •Nils Göth, Upayan Baul, Michael Bley, and Joachim Dzubiella — Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany

Packing and crowding are used in biology as mechanisms to (self-) regulate internal molecular or cellular processes based on collective signaling. Here, we study how the transition kinetics of an internal “switch” of responsive macromolecules is modified collectively by their spatial packing. We employ Brownian dynamics simulations of a model of Responsive Colloids, in which an explicit internal degree of freedom–here, the particle size–moving in a bimodal energy landscape self-consistently responds to the density fluctuations of the crowded environment. The bimodal energy landscape is motivated by existing two-state behavior like in protein folding or hydrogels with bimodal volume transitions. We demonstrate that populations and transition times for the two-state switching kinetics can be tuned over one order of magnitude by “self-crowding”. An exponential scaling law derived from a combination of Kramers’ and liquid state perturbation theory is in very good agreement with the simulations.
[1] Upayan Baul, NG, MB, and JD, J. Chem. Phys. 155, 244902 (2021).