Abstract: A member has a solid carrier and a thin oxide layer which is arranged thereon and consists of iridium oxide and/or possibly at least one oxide of at least one other metal belonging to the fifth or sixth period and to one of the subgroups 5b, 6b, 7b and 8 of the Periodic Table of chemical elements and/or zirconium oxide. The oxide layer is monocrystalline and therefore very stable. The member can serve, for example, for the formation of at least one electrode which serves as a proton donor and/or proton acceptor and/or for the measurement and/or change of the pH value and/or for a coulometric measurement or for holding biologically active molecules and at the same time as an electrode and/or optical sensor.

Abstract: A device for analyzing the metabolism of cells includes a supporting base which carries a pH measuring electrode, a control electrode designed for proton exchange with the liquid, a reference electrode, and a counterelectrode, and which, together with at least one other part, confines a hollow space containing the cells and a liquid. The electrodes are connected to electronic circuit elements. In the course of an analysis the pH value of the liquid is determined by means of the pH measuring electrode and the reference electrode. Between the control electrode and the counterelectrode an electric current is passed through the liquid and controlled such that the pH of the liquid is maintained at a constant preset value beneficial to the cells, by proton exchange with the control electrode. In addition, the amount of charge required for generating the current during the measuring period is determined to obtain a measure for the intensity of the metabolic process and thus for the vitality of the cells.