Rapid discrimination of DNA sequences using an engineered nanopore

Nanopores have been used for the development of biosensors for various substances and are currently under intense investigation as a potential tool for the entire genome sequencing. It has been demonstrated that an α-hemolysin protein pore covalently attached with a β-cyclodextrin adapter can differentiate single bases[1]; furthermore, single base discrimination could be achieved when a single-stranded DNA (ssDNA) is immobilized in the α-hemolysin pore[2]. Here, we show that when an unlabelled/unmodified double-stranded DNA (dsDNA) translocates through a properly engineered α-hemolysinnanopore, a sequence of sub-state blockage events is observed. Since different sequences of sub-state modulation events are produced by different DNA strands, they offer the potential as characteristic fingerprints to identify and discriminate the precise sequences of dsDNA samples.