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@PHDTHESIS{Niether:858802,
author = {Niether, Doreen},
title = {{T}hermophoresis of biological and biocompatible systems},
school = {Universität zu Köln},
type = {Dissertation},
address = {Köln},
reportid = {FZJ-2018-07642},
pages = {160 p.},
year = {2018},
note = {Dissertation, Universität zu Köln, 2018},
abstract = {Thermophoresis, or thermodiffusion, is mass transport
driven by a temperature gradient. This work focuses on
thermodiffusion in a biological context, where there are two
major applications for the effect: accumulation of a
component in microfluidic devices through a combination of
thermodiffusion and convection, and monitoring of protein
binding reactions through the sensitivity of thermodiffusion
to complex formation.Both applications are investigated, the
first as an accumulation process in the context of
origin-of-life theories and the second in light of the
question what we can learn from the observed changes in
thermodiffusion about modifications of the hydration shell
upon complex formation. While thermodiffusion in non-polar
liquids can be predicted with reasonable accuracy, the
description of aqueous systems is complicated as their
concentration and temperature dependence is often anomalous.
The underlying goal of this work is to gain a better
understanding of the interactions between components in an
aqueous mixture and how they influence thermodiffusion.We
find that the temperature dependence of a solute's
thermodiffusion correlates with its hydrophilicity and argue
that the temperature sensitivity of hydrogen bonds, which
dominate the interactions in aqueous solutions, might induce
a temperature dependence of the chemical potential. Such a
temperature dependence is as of yet not considered in
theoretical descriptions of thermodiffusion. Numerical
calculations show that the thermophoretic accumulation
process, as of yet only considered for the formation of RNA,
can accumulate formamide to high concentrations that would
allow the formation of prebiotic molecules. A heuristic
model is developed to illuminate the mechanism behind the
accumulation. Cyclodextrins and streptavidin were
investigated as model systems for biological complexes. It
is feasible that the exquisite sensitivity of
thermodiffusion to interactions with the surrounding solvent
allows inferences about changes in the protein's hydration
shell upon complex formation. Preliminary measurements on
streptavidin-biotin show a decreased hydrophilicity of the
complex, which is in qualitative agreement with increased
entropy of the hydration shell upon complex formation
calculated from calorimetric and neutron scattering
experiments.},
cin = {ICS-3},
cid = {I:(DE-Juel1)ICS-3-20110106},
pnm = {551 - Functional Macromolecules and Complexes (POF3-551)},
pid = {G:(DE-HGF)POF3-551},
typ = {PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/858802},
}