Detecting Transient Electrochemical Events by Converting Extremely Low Electrode Currents into Optical Signals Using Electrochemiluminescence

In the modern field of “nano-impact” electrochemistry, individual particles, vesicles, or macromolecules collide randomly with an ultramicroelectrode (UME), generating a series of low-intensity transient (Faradaic) current signals that stand out from the background current noise. However, the resolution of these short-lived signals associated with each individual collision “event” is often compromised, as amperometric measurement devices inherently cannot detect ultra-low currents (requiring filtering) without sacrificing response time (limited by the filter rise time). This major challenge requires disruptive instrumental approaches that no longer rely solely on reading the electrode current. Starting on an inspiring experimental idea, we recently developed an innovative measurement scheme capable of converting any electrochemical current generated by catalytic nano-collisions into a remote and sensitive emission of photons via an electrochemiluminescence (ECL) reaction (Anal Chem 2026, https://doi.org/10.1021/acs.analchem.5c05964).

In the framework of this PhD project, we propose to develop an optimal and universal opto-electrochemical configuration improving both sensitivity and temporal resolution of the current-to-ECL converter. The first part of the PhD work will consist in implementing an “on-chip” device, integrating microfluidics and transparent electrode material, to maximize the optical capture of the ECL. Several ECL systems will be then tested as light generation mechanism (in collaboration with Pr. Neso Sojic, Université de Bordeaux), seeking fast dynamics ECL conversion. Enabling sensitive, time-resolved “optical” detection of very low-current electrochemical processes, state-of-the-art applications in nano-collision electrochemistry and electrochemical microscopy will be explored in fine, particularly with regard to single bio-entities detection such as redox enzymes, whose measurement has so far remained beyond the reach of purely amperometric approaches.

ITODYS Lab, BioNano group (https://itodys.u-paris.fr/equipe-bionano/) Department of Chemistry, Université Paris Cité (Paris, France)

The ideal candidate should hold a recent Master’s degree in Analytical Chemistry or Physical Chemistry, with strong skills in electrochemistry. A practical experience in in optical microscopy, microfluidics or instrumentation will be a significant asset. Good interpersonal skills, scientific rigor and curiosity are essential.