Detecting Single Porphyrin Molecules in a Conically Shaped Synthetic Nanopore

Abstract
We report here the first example of abiotic resistive-pulse sensing of a molecular (as opposed to a particle or macromolecular) analyte. This was accomplished by using a conically shaped nanopore prepared by the track-etch method as the sensing element. It is possible to sense the molecular analyte because the small diameter opening of the conical nanopore (∼4.5 nm) is comparable to the diameter of the analyte molecule (∼2 nm).