  Fluidic channels at atomic scales regulate cellular trafficking and molecular
filtration across membranes and thus play crucial roles in the functioning of
living systems. However, constructing synthetic channels experimentally at
these scales has been a significant challenge due to the limitations in
nanofabrication techniques and the surface roughness of the commonly used
materials. Angstrom-scale slit-like channels address this challenge, as these
can be made with precise control over their dimensions and can be used to study
the fluidic properties of gases, ions and water at unprecedented scales. Here,
we provide a detailed fabrication method of the two-dimensional (2D)
angstrom-scale channels, which can be assembled as a single channel or up to
hundreds of channels made with atomic scale precision using layered crystals.
The procedure includes the fabrication of the substrate, flake, spacer layer,
flake transfers, van der Waals assembly, and post-processing. We further
explain how to perform molecular transport measurements with the angstrom-scale
channels, for the development of methods directed at unravelling interesting
and anomalous phenomena that help shed light on the physics of nanofluidic
transport systems. The procedure requires a total of 1 to 2 weeks for the
fabrication of the 2D channel device and is suitable for users with prior
experience in clean room working environments and nanofabrication.
