MODIFIED NANOPORES, COMPOSITIONS COMPRISING THE SAME, AND USES THEREOF

Transmembrane pores (e.g., nanopores) have been used to identify small molecules or folded proteins and to monitor chemical or enzymatic reactions at the single molecule level. The electrophoretic translocation of DNA across nanopores reconstituted into artificial membranes holds great promise for practical applications such as DNA sequencing, and biomarker recognition. However, translocation of double- stranded or single- stranded DNA through nanopores having internal surface facing negatively charged amino acids are not efficient. In particular, in nanopores having a negative internal surface charge and radii comparable to the Debye length of the solution, the surface potential produced by the electric-double layer (EDL) on the inner nanopore walls overlaps, resulting in a large electrostatic barrier for the entry of DNA into the nanopore. As a consequence, the translocation of DNA across such nanopores has only been observed using large nanopores (e.g. , 10 nm) or using small nanopores (e.g. , -3.5 nm) in high ionic strength solutions or under asymmetry salt concentrations.