Artifact‐Free 2D Mapping of Neural Activity In Vivo through Transparent Gold Nanonetwork Array

Abstract

With the rapid increase in the use of optogenetics to investigate the nervous system, there is a high demand for a neural interface that enables 2D mapping of electrophysiological neural signals with high precision during simultaneous light stimulation. Here, a gold nanonetwork (Au NN)-based transparent neural electrocorticogram (ECoG) monitoring system is proposed as implantable neural electronics. The neural interface enables accurate 2D mapping of ECoG neural signals without any photoelectric artifact during light stimulation. By using the Au NN, not only the transmittance of the microelectrodes is increased by 81% but also a low electrochemical impedance of 33.9 kΩ at 1 kHz with improved mechanical stability is achieved. It is demonstrated that the transparent microelectrode array records multichannel in vivo neural activities with no photoelectric artifact and a high signal-tonoise ratio. Propagation of neural dynamics of optically driven neural activities is also clearly visualized using the 2D Au NN microelectrode array. This transparent, flexible ECoG microelectrode array is a promising candidate for next-generation in vitro and in vivo neural interface for 2D mapping of neural dynamics.

Real-time monitoring of drug pharmacokinetics within tumor tissue in live animals

“…22 Our flexible probe minimizes such risks because its stiffness is sufficiently low (~270 nN•m) to approach that of tumor tissue. [37][38][39]…”

Red Light Optogenetics in Neuroscience

“…For topical parts of the brain, transparent intracranial EEG probes have been developed to be compatible with optogenetics ( Yang et al, 2020 ; Tian J. et al, 2021 ). For example, an acrylic template with gold electrodes has been utilized with opsin-based neural mapping in mice ( Seo et al, 2020 ). The flexibility of transparent intracranial EEG probes has also been improved.…”

Implantable Thin Film Devices as Brain-Computer Interfaces: Recent Advances in Design and Fabrication Approaches

“…Figure 2 shows some recent works of planar layout, which can be divided into flexible and soft structures according to the different substrate materials. [68]); (b) a parylene-based planar array with 56 microelectrodes and 6 macrodots (reprinted with permission from [84]); (c) an Au NN-based transparent ECoG monitoring system proposed as implantable planar neural electrodes; i: scale bar, 5 µm; ii: scale bar, 500 µm (reprinted with permission from [85]); (d) a flexible planar microelectrode device which could be inserted through a small cranial suture (reprinted with permission from [56]); (e) a soft, high-density and stretchable electrode grid (SEG) based on an inert, high-performance composite material; scale bar, 500 µm (reprinted with permission from [72]); (f) a PDMS-based soft, stretchable, 16-channel planar ECoG array (reprinted with permission from [86]); (g) the serpentine conductive leads embedded in polymer films attached on any soft planar substrate as the stretchable planar ECoG electrodes (reprinted with permission from [87]).…”

“…Besides, transparent electrodes are suitable to be combined with light stimulation modules for the bidirectional interaction with brain, and help reduce photoelectric artifacts in the recording signals induced by the light. A gold nanonetwork (Au NN)-based transparent neural electrocorticogram (ECoG) monitoring system was proposed in implantable neural electronics ( Figure 2c) [85]. By using the Au NN, the transmittance of microelectrodes increased by 81%, and furthermore a low electrochemical impedance of 33.9 kΩ at 1 kHz with improved mechanical stability was achieved.…”