Subcellular Neural Probes from Single-Crystal Gold Nanowires

Abstract

Size reduction of neural electrodes is essential for improving the functionality of neuroprosthetic devices, developing potent therapies for neurological and neurodegenerative diseases, and long-term brain–computer interfaces. Typical neural electrodes are micromanufactured devices with dimensions ranging from tens to hundreds of micrometers. Their further miniaturization is necessary to reduce local tissue damage and chronic immunological reactions of the brain. Here we report the neural electrode with subcellular dimensions based on single-crystalline gold nanowires (NWs) with a diameter of ∼100 nm. Unique mechanical and electrical properties of defect-free gold NWs enabled their implantation and recording of single neuron-activities in a live mouse brain despite a ∼50× reduction of the size compared to the closest analogues. Reduction of electrode dimensions enabled recording of neural activity with improved spatial resolution and differentiation of brain activity in response to different social situations for mice. The successful localization of the epileptic seizure center was also achieved using a multielectrode probe as a demonstration of the diagnostics potential of NW electrodes. This study demonstrated the realism of single-neuron recording using subcellular-sized electrodes that may be considered a pivotal point for use in diverse studies of chronic brain diseases.

Synthesis, Properties, and Biological Application of Perfect Crystal Gold Nanowires: A Review

“…original shape after the stress is removed as shown in Fig. 3(c) [29] . The combination of these mechanical properties would make the Au NW an interesting functional element in nanomechanical devices.…”

“…4) obtained from a four-probe device (inset in Fig. 4) [29] . It has electrical resistivity of 2.08 Â 10 À8 Um that is slightly lower than those of bulk Au (2.21 Â 10 À8 Um).…”

“…The average impedance of Au NW electrodes measured at 1 kHz in phosphate buffered saline solution is 5.6 MU ( Fig. 5(d)) [29] .…”

“…Reproduced from ref. [29] . Carbon nanotube pH-dependent chemical cleavage of disulfide bond Not controlled Quantum dot [38] BN nanotube pH-dependent chemical cleavage of disulfide bond Cytoplasm or nucleus Quantum dot [39] BN nanotube Electrochemical cleavage of AueS bond Cytoplasm or nucleus Quantum dot [40] SnO 2 nanowire Light-induced cleavage of photocleavable linkage Cytoplasm or nucleus Quantum dot [41] Si nanowire Diffusion Not controlled Nucleic acids, protein, peptide, small molecule [42] Au nanowire Electrochemical cleavage of AueS bond, electrophoretic detachment of electrostatically attached payloads Cytoplasm or nucleus Nucleic acids [32] .…”

“…Significant difference in the averaged first-peak values of Reproduced from ref. [29] . correlation coefficient means that Au NW electrodes could provide much higher spatial resolution than tungsten electrodes.…”