Solid-State Nanopores for the Detection and Characterization of Engineered Nanomaterials

The field of nanotechnology has pushed a remarkable transition towards exploring and harnessing unique properties and functionalities presented by engineered nanomaterials. An extensive investigation of their physicochemical properties is of paramount importance to gain insight into their structural–functional relationships. Recent developments in nanoscale characterization techniques, such as the use of solid-state nanopores have enabled single-molecule measurements, offering unprecedented insights into investigating nanomaterials on individual basis. The ability of nanopores to provide label-free and rapid detection and characterization of nanomaterials in solution based on their ionic current readout makes this technique a great candidate. However, its use in nanomaterials characterization is still limited by the need to tailor the nanopore aperture size to the size of the analyte, impeding the analysis of heterogenous samples due to low signal-to-noise-ratio readouts and low throughput. In this thesis, a polymer electrolyte nanopore-based approach for enhanced detection of engineered nanomaterial is demonstrated. The heterogenous nature of nanomaterials, including size, shape, assembly state, and functionalization layer is explored by means of ionic current recordings with solid-state nanopores based on pulled glass nanopipettes. Firstly, the analysis of DNA supramolecular assemblies in their native state is demonstrated in a rapid and high-throughput manner, employing the polymer electrolyte system. Furthermore, the fingerprinting and quantification of the assembly yield in different folding mixtures based on nanopore discriminants is showed with a fixed tailored pore size. Secondly, the polymer electrolyte nanopore system enabled the analysis of a range of functional nanomaterials, particularly targeting the analysis of metallic nanospheres, nanorods, plasmonic nanostars, and protein-based spherical nucleic acids. Overall, this thesis demonstrates the potential of solid-state nanopores as a versatile tool for interrogating different characteristics of engineered nanomaterials. These findings can contribute to complementing the toolbox of nanomaterials characterization and support innovation in nanomaterials development for many applications.