New Ways to Look through Nanopores

In this thesis, we have introduced palladium zero-mode waveguides (Pd ZMWs) as a valuable tool for biophysics research and have showcased several applications thereof. We started by using them as single-molecule sensors for free translocations of fluorophores, proteins, and voltage-driven translocations of DNA. By studying salt-gradient driven DNA translocations we could investigate the effect of diffusiophoresis on nanopore translocations. Next, we attached nucleoporins to Pd ZMWs, which allowed us to mimic the transport occurring through the nuclear-pore complex. Here, we found that the pore diameter plays a crucial role for the selectivity of NPC mimics. To explore this effect further, we developed a new method making the structure of NPC mimics visible using cryo-EM. In a last application, we could enable observations of single membrane-bound fluorophores despite a high-cytoplasmic fluorescence background in live-cells by letting them grow into Pd ZMW nanowells.