T1 In situ investigation of the cytotoxic and interfacial characteristics of titanium when galvanically coupled with magnesium using scanning electrochemical microscopy A1 Souto, Ricardo Manuel A1 Asserghine, Abdelilah A1 Ashrafi, Amir M. A1 Mukherjee, Atripan A1 Petrlak, Frantisek A1 Heger, Zbynek A1 Svec, Pavel A1 Richtera, Lukas A1 Nagy, Lívia A1 Nagy, Géza A1 Adam, Vojtech A2 Química A2 Departamento de Química Grupo de Electroquímica y Corrosión Instituto de Materiales y Nanotecnología K1 titanium K1 magnesium K1 galvanic coupling K1 local electrochemical activity K1 cytotoxic effects K1 pH variations K1 reactive oxygen species AB Recently, the cytotoxic properties of galvanically coupled Mg-Ti particles have been shown todifferent cells, although this cytotoxic effect has been attributed mainly to Mg due to itstendency to undergo activation when coupled with Ti forming a galvanic cell consisting of ananode (Mg) and a cathode (Ti). However, the role of the Ti cathode has been ignored inexplaining the cytotoxic effect of Mg-Ti particles due to its high resistance to corrosion. In thiswork, the role of titanium (Ti) in the cytotoxic mechanism of galvanically coupled Mg-Tiparticles was examined. A model galvanic cell was prepared to simulate the Mg-Ti particles.The electrochemical reactivity of the Ti sample and the pH change above it due to galvaniccoupling with Mg were investigated using scanning electrochemical microscopy (SECM). Itwas observed that the Ti surface changed from passive to electrochemically active whencoupled with Mg. Furthermore, after only 15 min galvanic coupling with Mg, the pH in theelectrolyte volume adjacent to the Ti surface increased to an alkaline pH value. The effects ofthe galvanic coupling of Ti and Mg, as well as of the alkaline pH environment, on the viabilityof Hs27 fibroblast cells were investigated. It was shown that the viability of Hs27 cellssignificantly diminished when Mg and Ti were galvanically coupled compared to when the twometals were electrically disconnected. Next, the generation of reactive oxygen species (ROS)increased when the Ti and Mg were galvanically coupled. Thus, although Ti usually exhibitedhigh corrosion resistance when exposed to physiological environments, an electrochemicallyactive surface was observed when galvanically coupled with Mg, and this surface mayparticipate in electron transfer reactions with chemical species in the neighboring environment;this participation resulted in the increased pH values above its surface and enhanced generationof ROS. These features contributed to the development of cytotoxic effects by galvanicallycoupled Mg-Ti particles. LK http://riull.ull.es/xmlui/handle/915/25284 UL http://riull.ull.es/xmlui/handle/915/25284 LA en DS Repositorio institucional de la Universidad de La Laguna RD 29-mar-2024