MnO₂ Nanoflower Integrated Optoelectronic Biointerfaces for Photostimulation of Neurons

Abstract

Optoelectronic biointerfaces have gained significant interest for wireless and electrical control of neurons. Three–dimentional (3D) pseudocapacitive nanomaterials with large surface areas and interconnected porous structures have great potential for optoelectronic biointerfaces that can fulfill the requirement of high electrode‐electrolyte capacitance to effectively transduce light into stimulating ionic currents. In this study, the integration of 3D manganese dioxide (MnO2) nanoflowers into flexible optoelectronic biointerfaces for safe and efficient photostimulation of neurons is demonstrated. MnO2 nanoflowers are grown via chemical bath deposition on the return electrode, which has a MnO2 seed layer deposited via cyclic voltammetry. They facilitate a high interfacial capacitance (larger than 10 mF cm−2) and photogenerated charge density (over 20 µC cm−2) under low light intensity (1 mW mm−2). MnO2 nanoflowers induce safe capacitive currents with reversible Faradaic reactions and do not cause any toxicity on hippocampal neurons in vitro, making them a promising material for biointerfacing with electrogenic cells. Patch‐clamp electrophysiology is recorded in the whole‐cell configuration of hippocampal neurons, and the optoelectronic biointerfaces trigger repetitive and rapid firing of action potentials in response to light pulse trains. This study points out the potential of electrochemically‐deposited 3D pseudocapacitive nanomaterials as a robust building block for optoelectronic control of neurons.

Capacitive and Efficient Near-Infrared Stimulation of Neurons via an Ultrathin AgBiS2 Nanocrystal Layer

“…Since in our previous studies we demonstrated that the use of P3HT on the biointerface had no adverse effect on cell survival, , at first we tested the effect of AgBiS 2 NCs on primary hippocampal cells by using devices without the P3HT layer. Morphological features of neurons during the 14-day culture period were maintained on ITO/ZnO/AgBiS 2 devices and showed no significant alteration in morphology with respect to the control group (Figure S9).…”