Support‐Free PEDOT:PSS Fibers as Multifunctional Microelectrodes for In Vivo Neural Recording and Modulation

Abstract

In vivo microelectrodes are essential for neuroscience studies. However, development of microelectrodes with both flexibility and multifunctionality for recording chemical and electrical signals in the same extracellular microspace and modulating neural activity remains challenging. Here, we find that pure PEDOT: PSS fibers (i.e., support-free) exhibit high conductivity, fast heterogeneous electron transfer, and suitable charge storage and injection capabilities, and can thus directly act as microelectrodes not only for chemical and electrophysiological recording in the same extracellular microspace, but also for electromodulation of neural microcircuit activity. Moreover, the microelectrodes mechanically match with neural tissues, exhibiting less foreign body responses. Given the multifunctionality, flexibility, and biocompatibility, the support-free PE-DOT:PSS-based microelectrodes offer a new avenue to microelectrode technology for neuroscience research, diagnostics and therapeutics.

Hydrogel-Coated Microelectrode Resists Protein Passivation of In Vivo Amperometric Sensors

“…As displayed in Figure C, upon intraperitoneal injection of insulin (8 U), the current response recorded with AOx/GOx-CSgel/PtNPs/CFME at 0.5 V decreased gradually after about 500 s, indicating a decrease in the glucose level in rat brain because insulin promotes the consumption of blood glucose. These above results are all consistent with previous reports and verify the sensing feasibility of hydrogel-coated microelectrodes. ,,− After the in vivo experiment, the electrodes were removed carefully and calibrated. The ratio of postsensitivity to presensitivity ( S post / S pre ) of hydrogel-coated microelectrodes is more than 90% for the three analytes (Figures D and S11–S13).…”

“…All animal procedures were in accordance with the guide for the care and use of laboratory animals from the Chinese Ministry of Health and approved by the Animal Care and Use Committee of Beijing Normal University. Animal experiments were performed with a method described in our earlier work. , Briefly, Rats were anesthetized with isoflurane (4% induction, 2% maintenance) through an R520 gas pump (RWD, China). Body temperature was maintained at 37 °C with a regulated heating blanket.…”

“…Animal experiments were performed with a method described in our earlier work. 19,51 Briefly, Rats were anesthetized with isoflurane (4% induction, 2% maintenance) through an R520 gas pump (RWD, China). Body temperature was maintained at 37 °C with a regulated heating blanket.…”

Biocompatible Microelectrode for In Vivo Sensing with Improved Performance

“…Conventional microelectrodes are based on "rigid" materials such as carbon fiber, and the Young's modulus (EY ≈ 60 to 680 GPA) significantly exceeds that of neural tissue (in the range of thousands to megabits). 44 Since implanted microelectrodes are usually fixed to the skull, brain micromovements due to respiration and vascular pulsation (physiological displacement) and mechanical and behavioral movements due to traction lead to relative between the microelectrodes and the host neural tissue. The resulting mechanical stress can further lead to tissue deformation, tearing, and shearing of the extracellular matrix and to aggravated BBB and vascular destruction.…”

“…To address the problem of a mechanical mismatch between CFE and brain tissue, Xu et al first prepared substrate-free PEDOT:PSS flexible polymer fiber microelectrodes by wet spinning (Figure 3a). 44 A series of postprocessing methods cause the fiber microelectrode with a low Young's modulus to have mechanical stability in water solution and to have high conductivity through improving the pathway and carrier concentration of PEDOT:PSS (Figure 3b). Neurochemicals have rapid heterogeneous electron transfer at the flexible PEDOT:PSS fiber microelectrode.…”