The minute release of various electroactive biomolecules emitted by a single living cell isolated in a Petri dish can be monitored in real time by an ultramicroelectrode positioned above the secreting cell. In this work, this platinized carbon fiber ultramicroelectrode analytical methodology is extended to the relation study between oxidative stress and effects of anti-tumoral species (FcdiOH, DP1 and Fc-OH-TAM) on breast cancer cells. The amperometric signal is collected by the carbon fiber electrode poised at hundred nanometers over a cancerous breast cell incubated with antitumoral species like ferrocifens. Local liberation of oxygen and nitrogen reactive species (ROS and RNS, namely H2O2, ONOO-, NO and NO2-) by these cell lines (MCF7 and MDA-MB-231) is analyzed. Morphological studies show that FcdiOH, DP1 and Fc-OH-TAM species have a significant antiproliferative effect. On one hand, treatments with Fc-diOH and particularly DP1 significantly increase ROS production. On the other hand, Fc (control) and Fc-OH-TAM have no or very little effect. This is quite surprising for Fc-OH-TAM, which has the strongest antiproliferative effect among all the tested ferrocifens. Fc-diOH and DP1 seem to induce an overproduction of NO and/or NO2-, as well as H2O2. This original comparison between morphological and electrochemical studies strives to show that ferrocifens act through two complementary paths, either the formation of a quinone methid (Fc-OH-TAM), or via a direct reaction (DP1, Fc-diOH).
