Gating Protein Transport in Solid State Nanopores
by Single Molecule Recognition
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Abstract
Control
of molecular translocation through nanoscale apertures
is of great interest for DNA sequencing, biomolecular filters, and
new platforms for single molecule analysis. However, methods for controlling
the permeability of nanopores are very limited. Here, we show how
nanopores functionalized with poly(ethylene glycol) brushes, which
fully prevent protein translocation, can be reversibly gated to an
“open” state by binding of single IgG antibodies that
disrupt the macromolecular barrier. On the basis of surface plasmon
resonance data we propose a two-state model describing the antibody–polymer
interaction kinetics. Reversibly (weakly) bound antibodies decrease
the protein exclusion height while irreversibly (strongly) bound antibodies
do not. Our results are further supported by fluorescence readout
from pore arrays and high-speed atomic force microscopy on single
pores. This type of dynamic barrier control on the nanoscale provides
new possibilities for biomolecular separation and analysis