Long‐term biocompatibility of implanted polymer‐based intrafascicular electrodes

Abstract

Polymer-based longitudinal intrafascicular electrodes (polyLIFEs) were chronically implanted into the sciatic nerve of white New Zealand rabbits (n=8) for a period of 6 months (hereafter referred to as the long-term group). The impact of the implantation procedure, as observed 6 months post surgery, was evaluated in a sham-treated control group (n=9). The contralateral sciatic nerve served as the control for each animal. Nerve-fiber counts, fiber diameters, and myelin thickness were estimated at the level of the implant site, 1.5 cm proximally, and 1.5 cm distally for both nerves in sham-treated and long-term groups. Implantation of polyLIFEs had no significant effect on fiber counts, nerve-fiber diameter, or myelin thickness. A slight increase in connective tissue in the vicinity of the implant site was evident in the long-term group, including a thin but dense capsule immediately surrounding the implanted electrode.

Acute Performance of the Thin-Film Longitudinal Intra-Fascicular Electrode

“…To date, the prior work has been based on handmade monopolar or bipolar electrodes, either made of Teflon ® insulated 25μm diameter Pt-Ir wires or metallized and insulated polyaramid filaments [10].…”

Stability and selectivity of a chronic, multi-contact cuff electrode for sensory stimulation in human amputees

“…In early chronic studies in human, intraneural interfaces have had challenges with failing electrode channels [13] and rising stimulation threshold [7,9]. However, chronic intraneural research is preliminary in humans and research continues to progress toward long-term stability [44,45].…”

Silicon Carbide Materials for Biomedical Applications

“…Research has indicated that there are many factors behind this problem, and the major contributors seem to be material biocompatibility, device geometry, and micro-motion of the brain within the skull. The hallmark of the problem is the development of a chronic immune response which continues well beyond the conclusion of the acute immune response initiated by the surgical trauma the device causes to neuronal and vascular tissue [134,[137][138][139]. Some studies indicate that device-related chronic immune response occurs regardless of the extent of neuronal damage and increases in intensity with longer implantation times [134,[139][140][141][142].…”