  Molecular carriers represent an increasingly common strategy in the field of
nanopore sensing to use secondary molecules to selectively report on the
presence of target analytes in solution, allowing for sensitive assays of
otherwise hard-to-detect molecules such as small, weakly-charged proteins.
However, existing carrier designs can often introduce drawbacks to nanopore
experiments including higher levels of cost/complexity and carrier-pore
interactions that lead to ambiguous signals and elevated clogging rates. In
this work, we present a simple method of carrier production based on
sticky-ended DNA molecules that emphasizes ease-of-synthesis and compatibility
with nanopore sensing and analysis. In particular, our method incorporates the
ability to flexibly control the length of the DNA carriers produced, enhancing
the multiplexing potential of this carrier system through the separable
nanopore signals they could generate for distinct targets. A proof-of-concept
nanopore experiment is also presented, involving carriers produced by our
method with multiple lengths and attached to DNA nanostructure targets, in
order to validate the capabilities of the system. As the breadth of
applications for nanopore sensors continues to expand, the availability of
tools such as those presented here to help translate the outcomes of these
applications into robust nanopore signals will be of major importance.
