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Integrated optrodes for optogenetics have been becoming a significant tool in neuroscience through the combination of offering accurate stimulation to target cells and recording biological signals simultaneously. This makes it not just be widely used in neuroscience researches, but also have a great potential to be employed in future treatments in clinical neurological diseases. To optimize the integrated optrodes, this paper aimed to investigate the influence of surface material and illumination upon the performance of the microelectrode/electrolyte interface and build a corresponding evaluation system. In this work, an integrated planar optrode with a blue LED and microelectrodes was designed and fabricated. The charge transfer mechanism on the interface was theoretically modeled and experimentally verified. An evaluation system for assessing microelectrodes was also built up. Using this system, the proposed model of various biocompatible surface materials on microelectrodes was further investigated under different illumination conditions. The influence of illumination on the microelectrode/electrolyte interface was the cause of optical artifacts, which interfere the biological signal recording. It was found that surface materials had a great effect on the charge transfer capacity, electrical stability and recoverability, photostability, and especially optical artifacts. The metal with better charge transfer capacity and electrical stability is highly possible to have a better performance on the optical artifacts, regardless of its electrical recoverability and photostability under the illumination conditions of optogenetics. Among the five metals used in our investigation, iridium served as the best surface material for the proposed integrated optrodes. Thus, optimizing the surface material for optrodes could reduce optical interference, enhance the quality of the neural signal recording for optogenetics, and thus help to advance the research in neuroscience. [ABSTRACT FROM AUTHOR]

The novel La-doped FeNiSe 4 /Fe 0.8 Ni 0.2 Se 2 /NF (La-FeNi-Se/NF) heterostructure catalyst was prepared by a facile selenization treatment to La-doped FeNi Prussian blue analogue(PBA) in-situ grown on foam nickel (NF). The optimized La-FeNi-Se-2/NF exhibits superior alkaline OER electrocatalytic activity with a low overpotential 158 mV at 10 mA cm−2, a small Tafel slope 35.6 mV dec−1 and long-time durability. [Display omitted] • A simple and efficient method for preparing La-doped FeNi-Se/NF heterostructure. • The optimized La-FeNi-Se-2/NF exhibits superior alkaline OER electrocatalytic activity. • This performance was superior to most reported FeNi-based OER electrocatalysts. It is of great value to explore non-noble and highly active electrocatalysts for oxygen evolution reaction (OER) to obtain reproducible and clean fuels. In this work, a novel La-doped FeNiSe 4 /Fe 0.8 Ni 0.2 Se 2 /NF (La-FeNi-Se/NF) heterostructure catalyst was prepared by a facile selenization treatment to La-doped FeNi Prussian blue analogue(PBA) in-situ grown on foam nickel (NF). The catalytic performance of La-FeNi-Se/NF was significantly enhanced by the doped La3+. As a result, the optimized La-FeNi-Se-2/NF exhibits superior alkaline OER electrocatalytic activity (overpotential 158 mV at 10 mA cm−2 and Tafel slope 35.6 mV dec−1) than FeNi-Se/NF and Ln-FeNi-Se/NF (Ln = Ce, Gd, Yb), and most reported FeNi-based OER electrocatalysts. The excellent electrocatalytic capability to OER is attributed to the doping FeNi-Se heterostructure with a suitable amount La3+. Also, the unique La-FeNi-Se-2/NF flower-like structure composed of nanograins can produce abundant active sites and enhance charge transfer, thereby further improving the catalytic performance. This work highlights an effective chemical and engineering method to prepare efficient electrochemical catalysts. [ABSTRACT FROM AUTHOR]