An Implantable Nanoelectrode for Simultaneous in-Situ Self-Referencing, Drug Delivery, and Reliable Fixed-Point Recording Within a Single Neuron

This paper reports a novel multifunctional implantable nanoelectrode (MINE) based on a θ-tube, featuring one channel with Ag/AgCl for self-referencing, another channel for injection, and a precisely exposed collection point on the tip for fixed-point recording of electromotive force (EMF) and pH values. The protective coating on the tip is selectively etched by the atmospheric microplasma jet, exposing the functional coating and θ-tube channels. Comparative analysis of curves of cyclic voltammetry (CV) and impedance-frequency, and stability of current and EMF of nanoelectrodes (NEs) with five different protective coatings for the first time confirms that the NE coated with Parylene-C offers superior detection reliability. Real-time recordings of intracellular EMF and pH values during in-situ self-referencing and injection demonstrate that the MINE provides stable and reliable intracellular fixed-point recording capability, along with the potential for in-situ drug delivery and in-vivo intracellular monitoring, which holds significant promise for accurate diagnosis, real-time monitoring, and in-situ treatment of neurological diseases.