A new mechanism based on electrochemiluminescence (ECL) may lead to serological tests that are faster, more cost-effective, and more reliable than those currently in use, according to research from the University of Bologna in cooperation with Roche Diagnostics, Basel, Switzerland, and Hitachi High Tech, Tokyo. In the study, serological tests using ECL had sensitivity levels 128% higher than current tests.
“The results we obtained mark a new milestone in the state of the art of signal enhancement of ECL-based immunoassays,” says Francesco Paolucci, PhD, leader of the research group and a professor of health economics and policy at the University of Bologna. “This milestone is the outcome of years and years of international research into electrochemistry and of a close synergy with research and development sectors.”

Serological tests work by translating chemical reactions—such as between a reagent and an antibody—into a measurable and visible signal. ECL produces a light signal in response to an electrochemical reaction. In the case of serological tests, ECL ‘switches on’ the antibodies as if they were lamps.

However, the ECL mechanism has some limitations. The molecules that are able to prompt the ECL reaction are in very low concentrations in the human blood. Therefore, highly sensitive techniques are needed to identify the antibodies in the blood. The results obtained by this research group seem to go in exactly this direction.

“Our work represents something unprecedented in the field of ECL because it relies on the enhancement of the signal as opposed to the enhancement of the target as it usually happens with enzymatic methods or polymerase chain reaction,” says Giovanni Valenti, PhD, study coordinator and researcher at the University of Bologna. “These results pave the way for the development of ultrasensitive serological tests.”

The researchers obtained a twofold result with this study. Not only did they refine the mechanisms regulating ECL analyses, they also employed these mechanisms to develop new reactants that allow for far more efficient serological tests.

“From these results, we managed to identify highly efficient reactants that are able to enhance the sensitivity of this technique way beyond that currently employed for serological tests,” says Alessandra Zanut, PhD, first author of the study and a researcher at the University of Bologna. “With this technique, we obtained an ECL signal enhancement up to 128% compared to current techniques.”


  1. Zanut A, Fiorani A, Canola S, et al. Insights into the mechanism of coreactant electrochemiluminescence facilitating enhanced bioanalytical performance. Nat Commun. 2020;11(1):2668; doi: 10.1038/s41467-020-16476-2.