Microfluidic block copolymer membrane arrays for nanopore DNA sequencing

Abstract

Nanopore DNA sequencing has the potential to provide significant improvements to DNA sequencing: it may decrease cost while increasing speed and portability. Due to fundamental limits on the speed of reading DNA as it moves through a nanopore, an array of nanopores is necessary to parallelize measurements for high speeds. Additionally, a practical nanopore sequencing device would benefit from the use of block copolymer membranes to house the nanopore proteins; block copolymers are more structurally and chemically stable than phospholipids. We have previously tailored membranes composed of a block copolymer to house the nanopore protein MspA for this purpose. In this work, we extend the use of this polymer to a membrane array. We find that when switching from our previous manual system to this microfluidic system, the nanopore protein MspA exhibits variable behavior despite the use of the same block copolymer solution as before. We establish a metric for quantifying this variability and investigate its cause. We find that the cause is likely the use of volatile and water-soluble solvents in a small channel volume. Finally, we demonstrate that MspA in these block copolymer membranes is able to translocate DNA similar to MspA behavior in lipid membranes. These results illustrate the viability of polymer membranes for nanopore-based sensors while highlighting the challenges inherent in the development of a practical nanopore DNA sequencing device.