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Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1Hz), typical LFP signals (0.1-80 Hz) and higher frequencies (80-600 Hz) using the same recording site would particularly benefit preclinical epilepsy research and could provide clinical biomarkers for improved seizure onset zone delineation. However, commonly used metal microelectrode technology suffers from instabilities that hamper the high-fidelity of DC-coupled recordings, which are needed to access signals of very low frequency. Here, we use flexible graphene depth neural probes (gDNP), consisting of a linear array of graphene microtransistors, to concurrently record DC-shifts and high frequency neuronal activity in awake rodents. We show that gDNPs can reliably record and map with high spatial resolution seizures, pre-ictal DC-shifts and seizure associated spreading depolarizations together with higher frequencies through the cortical laminae to the hippocampus in a mouse model of chemically-induced seizures. Moreover, we demonstrate functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow oscillations in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, and in particular epilepsy research, by allowing stable and chronic DC-coupled recordings.

A synergetic approach to enhance magnetoelectric effects (i.e., control of magnetism with voltage) and improve energy efficiency in magnetically actuated devices is presented. The investigated material consists of an ordered array of Co−Pt microdisks, in which nanoporosity and partial oxidation are introduced during the synthetic procedure to synergetically boost the effects of electric field. The microdisks are grown by electrodeposition from an electrolyte containing an amphiphilic polymeric surfactant. The bath formulation is designed to favor the incorporation of oxygen in the form of cobalt oxide. A pronounced reduction of coercivity (88%) and a remarkable increase of Kerr signal amplitude (60%) are observed at room temperature upon subjecting the microdisks to negative voltages through an electrical double layer. These large voltage-induced changes in the magnetic properties of the microdisks are due to (i) the high surface-area-to-volume ratio with ultranarrow pore walls (sub-10 nm) that promote enhanced electric charge accumulation and (ii) magneto-ionic effects, where voltage-driven O 2− migration promotes a partial reduction of CoO to Co at room temperature. This simple and versatile procedure to fabricate patterned "nano-in-micro" magnetic motifs with adjustable voltage-driven magnetic properties is very appealing for energy-efficient magnetic recording systems and other magnetoelectronic devices.

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Cell viability and release ion concentration of two newly developed Fe-based alloys.