Improvement of the ITC binding analysis methodology for the unspecific interaction between serum proteins and polymer brushes grafted to nanoparticles
The use of nanoparticles in consumer and industrial applications is widespread and proliferates annually. Their tunable physicochemical properties improved many products and processes. The utilization of nanoparticles is mostly unregulated or underregulated, which arouses urgent questions about t...
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Format: | Thesis-Doctor of Philosophy |
Language: | English |
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Nanyang Technological University
2023
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Online Access: | https://hdl.handle.net/10356/165155 |
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Institution: | Nanyang Technological University |
Language: | English |
Summary: | The use of nanoparticles in consumer and industrial applications is widespread
and proliferates annually. Their tunable physicochemical properties improved
many products and processes. The utilization of nanoparticles is mostly
unregulated or underregulated, which arouses urgent questions about the direct
and long-term effects on humans and the environment. Such questions are
insufficiently answered because analysis methods capable of probing the weak
interactions between proteins and particles have their own limitations. These
analytical obstacles can also curb the development of new nanoparticle
formulations.
Other reasons for these uncertainties regarding the biosafety of nanoparticles lie
in the complex interaction between nanoparticles with biomolecules, cells, and
organs. Biomedical nanoparticles are usually injected into the bloodstream or
directly into the target tissue. Due to the particle's attractive force, biomolecules
form a strongly bound “hard corona” and a highly dynamic “soft corona“. Softand hard corona are forming the “protein corona” , which composition is heavily
influenced by the physicochemical properties of the nanoparticle. The protein
corona is responsible for the cell-nanoparticle interaction and, therefore, also for
nanomaterials' ultimate biological fate. Unfortunately, current available
analytical methods either probe the protein corona with significant limitations
only.
This thesis addresses the complex nature of the protein corona and the limitation
and strengths of commonly used analytical methods. This work focuses on
measuring affinity, stoichiometry, and thermodynamic parameters of the weak
interaction between thermoresponsive polymer brushes densely grafted on small
superparamagnetic iron oxide nanoparticles (SPIONs) and blood proteins with
the rarely used isothermal titration calorimetry (ITC) method. This approach
showed that lysozyme and transferrin are not interacting with certainty with the
used SPIONs. On the other hand, the binding- and thermodynamic parameters of
the interaction of albumin and immunoglobulin G with SPIONs could be
determined at physiological protein concentrations. Additionally, ITC was used
to compare the interaction of albumin with SPIONs which have a shell consisting
of linear or cyclic polymers. In contrast to linear polymer shells, particles with cyclic brushes did not show interaction with albumin. Furthermore, the
sequestering of toxic heavy metal ions by a novel polymer was quantified with
ITC. The following work aims to improve the methodology of ITC for the
analysis of the interaction between core-shell nanoparticles with biomolecules
and ions. It compares ITC to other analytical methods generally accepted for
binding studies and could be used as a starting point for new studies on the protein
corona. |
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