Nanopores are versatile single-molecule sensors offering
a simple
label-free readout with great sensitivity. We recently introduced
the nanopore electro-osmotic trap (NEOtrap) which can trap and sense
single unmodified proteins for long times. The trapping is achieved
by the electro-osmotic flow (EOF) generated from a DNA-origami sphere
docked onto the pore, but thermal fluctuations of the origami limited
the trapping of small proteins. Here, we use site-specific cholesterol
functionalization of the origami sphere to firmly link it to the lipid-coated
nanopore. We can lock the origami in either a vertical or horizontal
orientation which strongly modulates the EOF. The optimized EOF greatly
enhances the trapping capacity, yielding reduced noise, reduced measurement
heterogeneity, an increased capture rate, and 100-fold extended observation
times. We demonstrate the trapping of a variety of single proteins,
including small ones down to 14 kDa. The cholesterol functionalization
significantly expands the application range of the NEOtrap technology.