Thesis presented February 15, 2022

Abstract:
Surface nanopatterning is a key point in the fields of applications covering microelectronics, photovoltaics or biosensors. The purpose of nanopatterning a surface is to increase the specific surface area to improve the performance of the devices. This is achieved by reducing the pitch between two adjacent motifs created by the nanopatterning. Despite the constant improvement of the state-of-the-art techniques currently used for the creation of such patterns, they reach physical limitations and become very expensive. These main limitations can be overcome with bottom-up approach using self-assembling molecules. Among the molecules with self-assembly capabilities, proteins are distinguished by their nature, which makes them intrinsically stable and robust under physiological conditions. However, the protein self-assemblies described in the literature are often monolayers and, therefore, present few grafting sites, which limits their application in the field of nanotechnology. In this work, we present a protein oligomerization domain capable of self-assembly, through head-tail interactions, creating a honeycomb structure. This structure presents dimensions below 10 nm. We showed that it was possible to modulate its anchor on different surfaces and that one pore of this honeycomb was composed of 40 stacked proteins. Moreover, it is possible to modify the amino acids present inside these pores without modifying the honeycomb structure. We also showed that the functionalization of this nanostructure was possible using divalent or trivalent metal ions. This opens the possibility of using this structure for applications in nanotechnology. In this context, we have evaluated the interest of its use in two types of biosensors: a colorimetric biosensor for glucose detection and a biosensor using surface plasmon resonance for the detection of volatile organic compounds. These results show the potential of this protein honeycomb to nanostructure surfaces and thus improve already existing devices.

Keywords:
self-assembly, protein, bio-inspired, nanotechnology, biosensor, grafting