<section id="sec1" style="margin: 0px 0px 8px; padding: 0px;"><ul style="margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding: 0px; list-style: outside none; color: rgb(77, 81, 86); font-family: Roboto, &quot;helvetica neue&quot;, helvetica, arial, sans-serif; font-size: 16px;"><li class="va-top ov-h" style="margin: 0px 0px 4px; padding: 0px; vertical-align: top; overflow: hidden; zoom: 1;"><span style="font-size: 14px; font-family: Helvetica;">In particular, the way the microbial cells approach a solid surface in the presence of an electric field remains&nbsp;unclear. It seems tacitly accepted that microbial cells reach the surface of polarised electrodes by random motion and that the electrode impacts biofilm development only during the phase of cell growth on the surface.</span></li><li class="va-top ov-h" style="margin: 0px 0px 4px; padding: 0px; vertical-align: top; overflow: hidden; zoom: 1;"><br></li></ul><p id="p0010" style="margin-bottom: 16px; padding: 0px;"><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">Now, It is becoming increasingly obvious that&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/microbial-biofilms" title="Learn more about microbial biofilms from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">microbial biofilms</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;have a natural tendency to exchange electrons with their support when they grow on a conductive surface</span></span><span style="font-family: Helvetica; font-size: 14px;">. For us, it is around two decades, and microbial electroactive biofilms have been the source of the so-called microbial electrochemical technologies&nbsp;</span><span style="font-family: Helvetica; font-size: 14px;">with a huge number of possible application fields such as the production of electrical energy&nbsp;</span><span style="font-family: Helvetica; font-size: 14px;">or hydrogen&nbsp;</span><span style="font-family: Helvetica; font-size: 14px;">effluent treatments </span><span style="font-family: Helvetica; font-size: 14px;">and metal recovery&nbsp;</span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">for example. Electroactive biofilms have also been essential roles in&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/microbiological-corrosion" title="Learn more about microbiologically influenced corrosion from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">microbiologically influenced corrosion</span></a>.</span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">&nbsp;Besides all it is the field of conventional&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/electrochemical-process" title="Learn more about electrochemical processes from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">electrochemical processes</span></a><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">, more and more cases of inter-species microbial&nbsp;</span><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/electron-transport" title="Learn more about electron transfers from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">electron transfers</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;are being discovered to be mediated by conductive solids.</span></span></span><img src="/media/django-summernote/2022-11-12/bb6aa5a1-87aa-4eae-b3ea-f377b71dac7d.png" style="width: 698.009px;"></p><p id="p0015" style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">Extensive it is fundamental research has led to great advances in our understanding of extracellular electron transfers inside biofilms and between biofilms and electrodes</span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">. Nevertheless, we still know very little about the early formation of electroactive biofilms. In particular, the way the&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/microbial-cell" title="Learn more about microbial cells from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">microbial cells</span></a><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">&nbsp;approach a solid surface in the presence of an electric field remains unclear. It seems tacitly accepted that microbial cells reach the surface of polarised electrodes by random motion and that the electrode impacts&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/biofilm-development" title="Learn more about biofilm development from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">biofilm development</span></a><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">&nbsp;only during the phase of cell growth on the surface. The possible impact of the electric field on the approach phase, before the cells reach the&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/electrode-surface" title="Learn more about electrode surface from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">electrode surface</span></a><span style="font-family: Helvetica; font-size: 14px;">, is rarely evoked.</span></span></span></span></p><p id="p0020" style="margin-bottom: 16px; padding: 0px;"><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">A few studies have pr osed that&nbsp;</span><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/bacterial-cell" title="Learn more about bacterial cells from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">bacterial cells</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;can migrate in the electric field as colloids that are uniformly charged</span></span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;or behave as dipoles</span><span style="font-family: Helvetica; font-size: 14px;">. In these cases, we have seen bacterial cells have been assumed to migrate passively, without the involvement of a specific sensing process. In contrast, a few reports have postulated that bacteria might detect local electric fields&nbsp;</span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">through chemotaxis, by sensing the&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/concentration-gradient" title="Learn more about concentration gradient from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">concentration gradient</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;of redox compounds</span></span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">. Some reports have described the inhibition of&nbsp;</span><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/cell-motility" title="Learn more about cell motility from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">cell motility</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;by an applied current, without evoking possible mechanisms</span></span><span style="font-family: Helvetica; font-size: 14px;">. Others have observed that the swimming speed of&nbsp;</span><span style="margin: 0px; padding: 0px; font-family: Helvetica; font-size: 14px;"><em style="margin: 0px; padding: 0px;"><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/shewanella" title="Learn more about Shewanella from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;">Shewanella</a></em></span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;species increases in the vicinity of a polarised electrode</span><span style="font-family: Helvetica; font-size: 14px;">. This effect is different from a passive migration process because the swimming speed was enhanced in all directions of motion rather than in the direction of the electric field only. Nevertheless, the effect was conditioned by the cells’ ability to exchange electrons with the electrode and therefore required initial contact with the electrode to be triggered. Apart from these few leads, the approach phase of bacterial cells towards a polarised surface is still very poorly documented.</span></p><p id="p0025" style="margin-bottom: 16px; padding: 0px;"><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">In contrast,&nbsp;</span><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/eukaryotic-cell" title="Learn more about eukaryotic cells from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">eukaryotic cells</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;have been widely demonstrated to develop sophisticated strategies to sense an electric field and use it to orient their motion</span></span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">. This property, called electrotaxis, has been shown to play key roles in essential&nbsp;</span><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/physiological-process" title="Learn more about physiological processes from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">physiological processes</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;such as tissue development&nbsp;</span></span><span style="font-family: Helvetica; font-size: 14px;">wound healing</span><span style="font-family: Helvetica; font-size: 14px;">, and organ formation</span><span style="font-family: Helvetica; font-size: 14px;">. The multiplicity of evidence of electrotaxis in eukaryotic cells prompted us to look for a possible bacterial electrotaxis-related strategy in the formation of electroactive biofilms.</span></p><ul><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">The main purpose of this study was to move forward in identifying and deciphering possible microbial electrotaxis by using a complex multi-species consortium. </span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">A new type of electrochemical set-up was designed to discriminate the impact of the electric field from that of the polarised electrode. Imposing an electric field through a solution requires electrochemical reactions to occur on the surface of the electrodes. </span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">It is consequently difficult to discriminate the impact of the electric field from that of the polarised electrode surface in a conventional electrochemical reactor because the electrodes that create the electric field act also as the electron source or sink for the electroactive species that reach them. The new experimental device and procedure described here made it possible to separate the two effects.</span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">It is thus evidenced here that an electric field enhances the formation of electroactive biofilms on solid surfaces. The electric field affects the&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/biofilm-formation" title="Learn more about biofilm formation from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">biofilm formation</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;through indirect action due to the ionic gradient created at the interface. </span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">This analysis leads us to consider the capacity of microbial cells to detect interfacial ionic gradients as a major motor of surface colonization.</span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">The results described here indicate that controlling local ionic gradients may be an efficient way to enhance or mitigate the formation of biofilms on solid surfaces. Obvious applications can be foreseen in all domains of microbial electrochemical technologies.</span></li><li style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;"> Beyond that, and in a more speculative way, considering the ubiquitous presence of endogenous electric fields in living organisms </span><span style="font-family: Helvetica; font-size: 14px;">and the huge number of interfaces that compose them, the results described here may also open up new research paths in the domains of biomedicine and physiology.</span></li></ul></section><section id="sec2" style="margin: 0px 0px 8px; padding: 0px;"><h2 id="sectitle0025" class="u-h3 u-margin-l-top u-margin-xs-bottom" style="margin-right: 0px; margin-left: 0px; padding: 0px; color: rgb(80, 80, 80); margin-top: 32px !important; margin-bottom: 8px !important; font-size: 1.2rem !important; line-height: 1.333 !important;"><span style="font-family: Helvetica; font-size: 14px;"><b>Materials and methods</b></span></h2><h2 id="sectitle0025" class="u-h3 u-margin-l-top u-margin-xs-bottom" style="margin-right: 0px; margin-left: 0px; padding: 0px; color: rgb(80, 80, 80); margin-top: 32px !important; margin-bottom: 8px !important; font-size: 1.2rem !important; line-height: 1.333 !important;"><b><span style="font-size: 14px;">Inoculum and media</span></b></h2><section id="sec2.1" style="margin: 0px 0px 8px; padding: 0px;"><p id="p0045" style="margin-bottom: 16px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">The inoculum solution was garden compost leachate prepared by filtering a mix of 1.5&nbsp;​L of garden compost (Lombricompost, Or Brun) and 2.25&nbsp;​L of tap water containing 60&nbsp;​mM KCl through a large-mesh cloth. The synthetic medium was a phosphate buffer solution supplemented or not with 60&nbsp;​mM of KCl. The phosphate buffer solution was obtained by mixing a solution of Na</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; bottom: -0.25em; font-family: Helvetica;">2</span><span style="font-family: Helvetica; font-size: 14px;">HPO</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; bottom: -0.25em; font-family: Helvetica;">4</span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;(9.47&nbsp;​g&nbsp;​L</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">-1</span><span style="font-family: Helvetica; font-size: 14px;">) and a solution of KH</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; bottom: -0.25em; font-family: Helvetica;">2</span><span style="font-family: Helvetica; font-size: 14px;">PO</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; bottom: -0.25em; font-family: Helvetica;">4</span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;(9.08&nbsp;​g&nbsp;​L</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">-1</span><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">) with a ratio of respectively 61-39% (v/v) to a final pH of 7.0. When indicated in the protocol, the synthetic medium was supplemented with 20&nbsp;​mM of&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/sodium-acetate" title="Learn more about sodium acetate from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">sodium acetate</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;and with 10&nbsp;​mL&nbsp;​L</span></span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">-1</span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;of macronutrients solution, 1&nbsp;​mL&nbsp;​L</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">-1</span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;of micronutrients solution, and 1&nbsp;​mL&nbsp;​L</span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">-1</span><span style="font-family: Helvetica; font-size: 14px;">&nbsp;of vitamin solution.</span></p></section><section id="sec2.2" style="margin: 0px 0px 8px; padding: 0px;"><h3 id="sectitle0035" class="u-h4 u-margin-m-top u-margin-xs-bottom" style="margin-right: 0px; margin-left: 0px; padding: 0px; color: rgb(80, 80, 80); margin-top: 24px !important; margin-bottom: 8px !important; font-size: 1rem !important; line-height: 1.4 !important;"><span style="font-family: Helvetica; font-size: 14px;">&nbsp;<b>Electrochemical set-up:</b></span></h3><div style="margin: 0px; padding: 0px;"><p id="p0050" style="margin-bottom: 16px; padding: 0px; color: rgb(46, 46, 46); font-family: NexusSerif, Georgia, &quot;Times New Roman&quot;, Times, STIXGeneral, &quot;Cambria Math&quot;, &quot;Lucida Sans Unicode&quot;, &quot;Microsoft Sans Serif&quot;, &quot;Segoe UI Symbol&quot;, &quot;Arial Unicode MS&quot;, serif; font-size: 18px;"><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">The electrochemical reactors were made by assembling three modified Schott glass bottles (diameter 101&nbsp;​mm, height 152&nbsp;​mm, Duran). The central compartment was separated from the two end compartments with a system constituted of a flat&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/gasket" title="Learn more about gasket from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">gasket</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;cut from a rubber foil with an outer diameter of 5&nbsp;​cm and an inner diameter of 2&nbsp;​cm, a membrane with 0.2-μm cut-off threshold (outer diameter 5&nbsp;​cm, Pall SAS France), a carbon cloth electrode (outer diameter 3&nbsp;​cm, PaxiTech SAS France) electrically connected with a platinum wire, and a second rubber gasket identical to the first one. Such a separation system was arranged between the central compartment and each of the two end compartments, with the carbon cloth electrode facing the central compartment. According to the inner diameter of the flat rubber gasket (2&nbsp;​cm), the surface area of the carbon cloth electrodes exposed to the solution was 3.1&nbsp;​cm</span></span><span style="margin: 0px; padding: 0px; font-size: 14px; line-height: 0; position: relative; vertical-align: baseline; top: -0.5em; font-family: Helvetica;">2</span><span style="font-family: Helvetica; font-size: 14px;">. Sealing was achieved by pressing the system with an external frame equipped with four bolts.</span><img src="/media/django-summernote/2022-11-12/9ac3710b-3ef2-44a1-b4a4-417199de178f.png" style="width: 100%;"></p><div><p id="p0055" style="margin-bottom: 16px; padding: 0px; color: rgb(46, 46, 46); font-family: NexusSerif, Georgia, &quot;Times New Roman&quot;, Times, STIXGeneral, &quot;Cambria Math&quot;, &quot;Lucida Sans Unicode&quot;, &quot;Microsoft Sans Serif&quot;, &quot;Segoe UI Symbol&quot;, &quot;Arial Unicode MS&quot;, serif; font-size: 18px;"><span style="font-family: Helvetica; font-size: 14px;">&nbsp;Two metallic electrodes were electrically connected with a 2-mm-diameter screwed titanium wire. The electric field was established between these two metallic electrodes by applying a voltage of 8&nbsp;​V during 3&nbsp;​h (or 2&nbsp;​h when indicated) between the DSA used as the anode and the SS electrode used as the cathode, which was separated by around 27&nbsp;​cm.</span></p><p id="p0060" style="margin-bottom: 16px; padding: 0px; color: rgb(46, 46, 46); font-family: NexusSerif, Georgia, &quot;Times New Roman&quot;, Times, STIXGeneral, &quot;Cambria Math&quot;, &quot;Lucida Sans Unicode&quot;, &quot;Microsoft Sans Serif&quot;, &quot;Segoe UI Symbol&quot;, &quot;Arial Unicode MS&quot;, serif; font-size: 18px;"><span style="margin: 0px; padding: 0px;"><span style="font-family: Helvetica; font-size: 14px;">When necessary, a saturated calomel reference electrode (SCE, Radiometer, +0.241&nbsp;​V vs SHE) and a platinum grid used as the counter electrode were introduced in the central compartment and each of the two carbon cloth electrodes was individually polarised as a working electrode at -0.20&nbsp;​V/SCE with a multi-channel&nbsp;</span><a href="https://www.sciencedirect.com/topics/engineering/potentiostat" title="Learn more about potentiostat from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">potentiostat</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;(N-stat set-up,&nbsp;</span></span><a href="https://www.sciencedirect.com/topics/engineering/biologics" title="Learn more about Biologic from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(46, 46, 46); color: rgb(46, 46, 46); word-break: break-word; text-underline-offset: 1px;"><span style="font-family: Helvetica; font-size: 14px;">Biologic</span></a><span style="font-family: Helvetica; font-size: 14px;">&nbsp;SA, France).</span></p></div></div></section></section>