Intracellular Neural Recording with Pure Carbon Nanotube Probes

Abstract

The computational complexity of the brain depends in part on a neuron’s capacity to integrate electrochemical information from vast numbers of synaptic inputs. The measurements of synaptic activity that are crucial for mechanistic understanding of brain function are also challenging, because they require intracellular recording methods to detect and resolve millivolt- scale synaptic potentials. Although glass electrodes are widely used for intracellular recordings, novel electrodes with superior mechanical and electrical properties are desirable, because they could extend intracellular recording methods to challenging environments, including long term recordings in freely behaving animals. Carbon nanotubes (CNTs) can theoretically deliver this advance, but the difficulty of assembling CNTs has limited their application to a coating layer or assembly on a planar substrate, resulting in electrodes that are more suitable for in vivo extracellular recording or extracellular recording from isolated cells. Here we show that a novel, yet remarkably simple, millimeter-long electrode with a sub-micron tip, fabricated from self-entangled pure CNTs can be used to obtain intracellular and extracellular recordings from vertebrate neurons in vitro and in vivo. This fabrication technology provides a new method for assembling intracellular electrodes from CNTs, affording a promising opportunity to harness nanotechnology for neuroscience applications.

Penetration of Cell Membranes and Synthetic Lipid Bilayers by Nanoprobes

“…Nanofabricated devices, including nanostraws (1-3), nanowires (4-7), nanoneedles (8)(9)(10)(11)(12), and nanoelectrodes (13)(14)(15)(16)(17)(18)(19)(20)(21)(22), are increasingly being investigated as tools for cellular studies, but these structures do not readily insert through the cell membrane (2)(3)(4)(5)13,23), and assessing when (or whether) penetration has occurred is difficult due to the nanoscale features of the probe-membrane interface. To design cell-penetrating nanoprobes, a systematic approach is needed to describe nanostructure-membrane interactions at relevant temporal and spatial scales, particularly the processes of nanoprobe insertion through (3,(8)(9)(10)(11)(12)(13)15,18,24,25) or fusion with (14,16,19,(26)(27)(28) the plasma membrane.…”

Electrochemical Nanoprobes for Single-Cell Analysis

“…Lieber's group, for instance, developed a nanoscale field effect transistor (nanoFET) based on a kinked nanowire that was able to penetrate living cells and record intracellular potentials. 6 Similarly, Angle et al starting from conventional tungsten microelectrodes 9 and Yoon et al from a pure carbon nanotube 10 developed nanoelectrodes capable of intracellular recordings.…”

Implanted intracortical electrodes as chronic neural interfaces to the central nervous system

“…Already, carbon nanotube coatings have been used to increase biocompatibility of electrode microarrays and were found to improve quality of recordings by lowering impedance and increasing charge transfer [63,64]. Further work has continued in using carbon nanotubes for intracellular recording [65] with promising results. Additionally, proposed methods for creating microarrays of carbon nanotubes for intracortical recording had been proposed [66], and recently successfully implemented with promising in vitro results [67].…”