Flexible Neural Probes with Electrochemical Modified Microelectrodes for Artifact-Free Optogenetic Applications

Abstract

With the rapid increase in the use of optogenetics to investigate nervous systems, there is high demand for neural interfaces that can simultaneously perform optical stimulation and electrophysiological recording. However, high-magnitude stimulation artifacts have prevented experiments from being conducted at a desirably high temporal resolution. Here, a flexible polyimide-based neural probe with polyethylene glycol (PEG) packaged optical fiber and Pt-Black/PEDOT-GO (graphene oxide doped poly(3,4-ethylene-dioxythiophene)) modified microelectrodes was developed to reduce the stimulation artifacts that are induced by photoelectrochemical (PEC) and photovoltaic (PV) effects. The advantages of this design include quick and accurate implantation and high-resolution recording capacities. Firstly, electrochemical performance of the modified microelectrodes is significantly improved due to the large specific surface area of the GO layer. Secondly, good mechanical and electrochemical stability of the modified microelectrodes is obtained by using Pt-Black as bonding layer. Lastly, bench noise recordings revealed that PEC noise amplitude of the modified neural probes could be reduced to less than 50 µV and no PV noise was detected when compared to silicon-based neural probes. The results indicate that this device is a promising optogenetic tool for studying local neural circuits.

A Review: Research Progress of Neural Probes for Brain Research and Brain–Computer Interface

“…To minimize the effect of optoelectronic artifacts, highly transparent materials such as graphene [ 52 ] or indium tin oxide [ 105 ] have been used as electrode materials. Flexible polymer-based substrates to eliminate PV-induced artifacts are also a good option [ 106 , 107 , 108 ].…”

Dimensionality Reduction and Prediction of Impedance Data of Biointerface

“…To measure the accuracy of predicted DF as an absolute or quantitative value, we calculated the difference between the last value of the actual DF signal and the last value of the predicted one. Then, we normalized it to the maximum range of the actual DF, which gave us the relative error of the predicted signal; thus, (1-error) expresses the accuracy of the equality between the actual and the predicted DF as shown in Equation (3).…”

“…The primary goal of biointerface technology is the understanding of interactions between biomolecules and corresponding surfaces or mediums, which has recently been considered significant in the fields of biology, biotechnology, diagnostics, and medicine [2]. Biointerface technology has widespread applications, for example, but not limited to, neural interfaces that deal with the nervous system for recording and stimulating purposes [3], pathogenesis and pathogen detection [4], membrane-based biosensing [5], nanotube/nanoparticle interfaces and cells in engineered microenvironments, and regenerative medicine [6].…”

“…1 Root mean square of sinusoidal electric signal; 2 nanoZ Impedance Tester (Plexon, Texas);3 Gamry Reference 600 Potentiostat (Gamry Instruments, Warminster, PA, USA); 4 0.01 M phosphate-buffered saline (PBS) solution (P4417, tablet diluted in 200 mL distilled water, Merck KGaA, Darmstadt, Germany).…”

Flexible Neural Probes with Optical Artifact-Suppressing Modification and Biofriendly Polypeptide Coating

“…Furthermore, the PEC noise (up to 200 µVpp) on the metal-electrolyte interface can be mitigated by using electrochemical modification of materials with a band gap of larger than 3.26 eV, such as counterion-doped PEDOT, Sn-doped indium oxide or graphene [24,25]. In a previously published work [26], it was demonstrated that graphene oxide-doped PEDOT (PEDOT-GO) can effectively reduce PEC noise. However, direct comparison of electrochemical performance, stability and PEC noise of the PEDOT-GO modifications with the PEDOT-PSS modifications has not been reported.…”