Biohybrid Membrane Formation by Directed Insertion of Aquaporin into a Solid-State Nanopore

Biohybrid nanopores combine the durability of solid-state
nanopores
with the precise structure and function of biological nanopores. Particular
care must be taken to control how biological nanopores adapt to their
surroundings once they come into contact with the solid-state nanopores.
Two major challenges are to precisely control this adaptability under
dynamic conditions and provide predesigned functionalities that can
be manipulated for engineering applications. In this work, we report
on the computational design of a distinctive class of biohybrid active
membrane layers, built from the directed-insertion of an aquaporin-incorporated
lipid nanodisc into a model alkyl-functionalized silica pore. We show
that in an aqueous environment when a pressure difference exists between
the two sides of the solid-state nanopore, the preferential interactions
between the hydrocarbon tail of the lipid molecules that surround
the aquaporin protein and the alkyl group functionalizing the interior
surface of the silica nanopore enable the insertion of the aquaporin-incorporated
lipid shell into the nanopore by forcing out the water molecules.
The same preferential interactions are responsible for the structural
stability of the inserted aquaporin-incorporated lipid shell as well
as the water sealing properties of the lipid–alkyl interface.
We further show that the aquaporin protein stabilized in the alkyl-functionalized
silica nanopore preserves its biological structure and function in
both pure and saline water, and, remarkably, its water permeability
is equal to the one measured in the biological environment. The designed
biohybrid membrane could pave the way for the development of durable
transformative devices for water filtration.