Neural Stimulation and Recording with Bidirectional, Soft Carbon Nanotube Fiber Microelectrodes

TLDR

The development of microelectrodes capable of safely stimulating and recording neural activity is essential for prosthetic devices, brain‑machine interfaces, and therapies for neurological disorders, yet metal electrodes are limited by poor electrochemical properties, high stiffness, and bending fatigue. The study demonstrates neural recording and stimulation using carbon nanotube (CNT) fiber electrodes. CNT fiber electrodes are employed to record and stimulate neural activity. In vitro, CNT fiber electrodes exhibit markedly lower tissue contact impedance than state‑of‑the‑art metal electrodes, enabling single‑neuron recording without surface treatment; in vivo, they stimulate neurons as effectively as metal electrodes with tenfold larger surface area while inducing a significantly reduced inflammatory response, and they can record neural activity for weeks, supporting long‑term stable multifunctional interfaces.

Abstract

The development of microelectrodes capable of safely stimulating and recording neural activity is a critical step in the design of many prosthetic devices, brain-machine interfaces, and therapies for neurologic or nervous-system-mediated disorders. Metal electrodes are inadequate prospects for the miniaturization needed to attain neuronal-scale stimulation and recording because of their poor electrochemical properties, high stiffness, and propensity to fail due to bending fatigue. Here we demonstrate neural recording and stimulation using carbon nanotube (CNT) fiber electrodes. In vitro characterization shows that the tissue contact impedance of CNT fibers is remarkably lower than that of state-of-the-art metal electrodes, making them suitable for recording single-neuron activity without additional surface treatments. In vivo chronic studies in parkinsonian rodents show that CNT fiber microelectrodes stimulate neurons as effectively as metal electrodes with 10 times larger surface area, while eliciting a significantly reduced inflammatory response. The same CNT fiber microelectrodes can record neural activity for weeks, paving the way for the development of novel multifunctional and dynamic neural interfaces with long-term stability.