Five apparent steps in the ssDNA position profile can be observed, each representing a permeation event of a single nucleotide. We take the third step as an illustration [from (c) to (d) in Fig. 2]. When the nucleotide of the ssDNA reached the pore, it was trapped at the entrance (see Fig. 2(c)) and then the pulling force increased gradually [from (c) in Fig. 2(b)], resulting from the severe geometric restraint by the pore and the interaction with the pore. Subsequently, when the pulling force exceeded a peak value [i.e., (d) in Fig. 2(b)],the base was released by the pore rapidly (Fig. 2(d)). Thus, this force peak can reflect the passage process of the third nucleotide of the ssDNA across the pore. The obtained force signal in Fig. 2(b) is therefore at a resolution of a single base, with each peak corresponding to a nucleotide. The demon- strated “stop and go” ratchet-like motion of ssDNA can significantly slow down DNA translocation and, thus, increase the detention time of nucleotides inside the nanopore, which could significantly enhance the signal resolution of existing nanopore sequencing techniques.31 We also noted that when the last base of A6 reached the nanopore, it rotated remarkably to easily pass through the nanopore such that it was “missed” in the position and force curves.