Liu, K. et al. Nat. Commun. 10, 3 (2019).

Nanopore sequencing allows the reading of individual, long DNA molecules, but the protein-based nanopores currently used for nucleotide-level resolution are only one form of nanopore. The need to embed them in a lipid bilayer and their larger structure are drawbacks that could be addressed with solid-state pores. Liu et al. focus on thin MoS2 pores and show that they can detect topological alterations in DNA. The researchers created a DNA molecule with a single-strand segment sandwiched between two double-stranded ends. They measured the change in current as the DNA translocated through the 3-nm pore and saw that while only 10% of events were complete translocations of the entire molecule, the different strand topologies could be distinguished. When they probed a single-strand DNA with a small barcoded oligo hybridized close to one end, the current trace clearly distinguished the barcoded region. The authors see potential utility of these thin solid-state pores as biomarker sensors; the pores could also be used to probe whether DNA of unknown sequence pairs with known barcodes.