Biomolecule Trapping With Stimuli-Responsive Polymer Coated Nanostructures

Doctoral thesis, 2022

Detecting and analyzing single or a few biomolecules such as proteins is crucial to develop novel drugs and understand disease formation. In human organisms alone, at least around 20 000 different proteins exist. However, only around a quarter of these have been studied for their function, behavior in different environments and structural change over time. Mostly until now, biomolecules have been investigated in bulk. This means that if a smaller fraction of the same protein sample behaves differently over time, it will not be detected as the majority of the other proteins will “mask” their detection. Nowadays, an increasing number of tools allow to study single or a few proteins, which could present a clearer understanding of how the whole sample might behave. Nevertheless, the analyses are usually limited as the protein’s freedom is often restricted in some way, the molecules move out of the focal point before they can be observed, or the experimental environment does not mimic the native picture in full.
To tackle some of the mentioned challenges, we envisioned a system, which would allow proteins to freely roam around at physiological conditions while confining them in the detection spot. Such a volume should be relatively tiny as an average protein’s diameter ranges between 3 and 6 nanometers. Therefore, a platform containing some sort of a nanocavity with a tunable gating mechanism could deem advantageous in achieving this.
Nanosized objects are often difficult for people to relate to as they are incredibly small. An example of such scale could be by roughly comparing the diameters of a common football ball and the Sun.
In this thesis, a novel platform to trap and release biomolecules on demand was designed and its working principle is shown. The platform is made of out multiple or a few nanostructures (or nanowells), which are the supports for the confinement of proteins. Furthermore, they are coated with temperature-responsive polymer brushes, which act as a smart-gate and do not damage or restrict these biomolecules in any way. Finally, trapping and analyzing proteins in many nanocavities in parallel at the same time could possibly allow to increase the throughput of coming investigations manyfold.
All in all, we highly hope that our manufactured system combined with other methods will help other researchers and medical facilities to better understand how various proteins (other biomolecules as well) function, change their shape over time and interact with others in the future.