Solid-state nanopore detection of osmylated bases.

<p><b>(a)</b> Schematic view of the nanopore ssDNA detection system. Voltage is applied across a SiN membrane containing a ~1.6 nm diameter nanopore using a pair of electrodes, leading to a steady-state ion current across the pore. When negatively charged DNA molecules are added to the <i>cis</i> chamber they are electrophoretically drawn through the nanopore to the positively charged electrode in the trans chamber. “Os*” tags are shown to represent osbipy molecules as they preferentially bind to thymidine bases (represented in red). <b>(b)</b> Reaction of OsO₄ with bipyridine to form the bipy-OsO₄ reactive complex. The complex then reacts with dTMP to form the osmylated adduct.