Single Molecule DNA Analysis Based on Atomic-Controllable Nanopores in Covalent Organic Frameworks
Xiaolei Xing, Qiaobo Liao, Saud Asif Ahmed, Dongni Wang, Shibin Ren, Qin Xiang, Xin‐Lei Ding, Kai Xi, Lina Ji, Kang Wang, Xing‐Hua Xia
Abstract
We explored the application of two-dimensional covalent organic frameworks (2D COFs) in single molecule DNA analysis. Two ultrathin COF nanosheets were exfoliated with pore sizes of 1.1 nm (COF-1.1) and 1.3 nm (COF-1.3) and covered closely on a quartz nanopipette with an orifice of 20 ± 5 nm. COF nanopores exhibited high size selectivity for fluorescent dyes and DNA molecules. The transport of long (calf thymus DNA) and short (DNA-80) DNA molecules through the COF nanopores was studied. Because of the strong interaction between DNA bases and the organic backbones of COFs, the DNA-80 was transported through the COF-1.1 nanopore at a speed of 270 μs/base, which is the slowest speed ever observed compared with 2D inorganic nanomaterials. This study shows that the COF nanosheet can work individually as a nanopore monomer with controllable pore size like its biological counterparts.