Silent translocations in nanopores

Traditionally, nanopore research relies on electrical measurements to study the passage of materials, and these methods have been instrumental in understanding how various chemical species, including ions, small molecules, and polymers, interact with nanopores. However, it appears there are situations when certain molecules pass through nanopores without producing any detectable electrical signature, thus leaving no electrical trace.

The recent study, led by Daniel Burden et al., sheds light on this previously elusive phenomenon, dubbed “silent translocation.” The research team investigated the translocation of a Cyanine 5 derivative (sCy5a) through α-hemolysin (αHL) nanopores. What makes their approach quite remarkable is the simultaneous use of single-molecule fluorescence and single-channel electrical recordings.

To accomplish this, the authors used Nanion’s Orbit mini bilayer recording device with a MECA 4 OPTO-INV kit positioned on a Nikon Ti-E inverted optical microscope, custom-adapted for confocal operation. This setup enabled simultaneous optical and electrical recordings in free standing artificial lipid bilayers and allowed the researchers to observe the passage of sCy5a through the nanopore, even though it left no electrical signature.

This study challenges the long-held belief that molecular translocation always correlates with detectable electrical events. It highlights that silent translocations are more common than previously thought, thus urging scientists to reconsider existing theories and models.

Find the full article here: https://pubs.acs.org/doi/10.1021/acs.analchem.3c02329

Learn more about simultaneous optical and electrical recordings in free standing artificial lipid bilayers.