Novel PMMA Polymer-Based Nanopores Capable of Detection and Discrimination Between Structurally Different Biomolecules

We report, for the first time, the use of single poly (methyl-methacrylate) (PMMA) polymer-based nanopores to not only detect the translocating biomolecules of dsDNA and BSA in individual populations, but also distinguish between them in a mixed population, based on the obtained depths (ⁱBlock) and durations (t_D) of the ionic current blockade events. Quantitative analyzes of current blockade events induced by separate populations of dsDNA and BSA molecules translocating through single PMMA-based nanopores revealed a mean ⁱBlock value of 22.4 ± 0.69 pA with a t_D of 0.202 ± 0.009 ms, and a mean ⁱBlock value of 60.14 ± 0.19 pA with a t_D of 0.59 ± 0.08 ms for dsDNA and BSA molecules, respectively. Evaluation of translocation events by dsDNA and BSA molecules in a mixed population through single nanopores indicated two distinct groups of current blockade events, extrapolation of which could perfectly correlate the group demonstrating ⁱBlock values of 13-38 pA to the dsDNA molecules, whereas the group demonstrating ⁱBlock values of 52-73 pA to the BSA protein molecules transporting through the nanopores. Analysis of the data suggests that the majority of dsDNA or BSA protein molecules translocating through the nanopores are in their partially folded conformation. This paper is an important milestone in the development of polymer-based solid-state nanopore devices for fast and accurate biomolecule detection, differentiation/discrimination, and future structural characterization.