Sprecher
Beschreibung
The study of biological systems in all its complexity has proven to be quite difficult. As a result, the use of simpler model systems is common. Two of the central phenomena that are becoming recognized in biological systems are phase separation and self-assembly. In vivo, both of these are common for different types and combinations of proteins and RNA [1]. However, studying these systems directly is difficult and the starting materials can be expensive to obtain.
Synthetic polypeptides, specifically Polyaminoacids, have proven to be a versatile model system for polymer assembly, coacervation and phase separation [2][3]. In this work, Polyarginine and Polyaspartic Acid are combined to study both processes as a function of temperature and salt concentration.
At lower temperatures and with no, very little or a lot of added salt, the self-assembly of the solid phase is studied using primarily X-ray and neutron scattering methods such as SAXS and SANS as well as tensile testing. Large scale structural ordering and self-assembly is observed.
At higher temperatures and/or intermediate salt concentrations, the phase separation of the liquid phases will be studied using microscopy and DLS as well as rheology. The phases are highly concentrated and viscous. This work will also focus on tuning the properties of these phases to mimic specific systems and compare them to simple biological models. In the future, the plan is to also use NSE and QENS to study the internal dynamics of these concentrated phases.
[1] B. Wang, Signal Transduction and Targeted Therapy, 6, 290 (2021).
[2] W.Wenjie, ChemBioChem, 26, e202400773 (2025).
[3] A.Levin, Nature Reviews Chemistry, 4, 615-634 (2020).