Digital counting individual nucleic acid molecule is of great significance for fundamental biological research and accurate diagnosis of genetic diseases, which is hard to achieve with existing single-molecule detection technologies. Researchers at the University of Science and Technology Beijing report a novel one-by-one single-molecule counting method for digital quantification of SARS-Cov-2 RNA. This method uses one fluorescent micromotor functionalized with peptide nucleic acids (PNAs) to specially capture one target RNA molecule. The RNA-micromotors can be propelled by the electric field to target district and accurately counted. Moreover, the method can also clearly discriminate one-base mutation in the target RNAs, indicating the great potential for clinical diagnostics and virus traceability survey.
Schematic diagrams of single-molecule counting of SARS-CoV-2 RNA
based on electric field propelled PFFM-RNA
(A) Capturing one target RNA molecule with one PFFM and the motion of PFFM-RNA in the capillary under the applied electric field. (B) The structure of the capillary chip instrument. (C) The imaging of PFFM-RNA.