Detection of polymeric entities through Single-Entity electrochemistry via electrocatalytic amplification

Single-entity electrochemistry (SEE) was used to investigate the stochastic collisions of polymeric entities. Electrocatalytic amplification of π-conjugated polyelectrolytes (CPEs) using the oxidation of ammonia borane (AB) was employed for detecting polymeric entities. AB oxidation, while slow on a carbon ultramicroelectrode (C-UME), is catalyzed by the active sites of CPEs, which have positive polarons formed along their backbone owing to collisions with the electrode at a sufficiently positive potential (+0.5 V). The collision frequency of the CPE was proportional to the increase in concentration, and the charge distribution of particle collisions tended to be similar to the size distribution obtained by dynamic light scattering (DLS). By applying this method in combination with optical techniques, additional information can be obtained at the molecular level, thereby contributing to the fields of biosensors, and solar/fuel cells.