Foreign body response to intracortical microelectrodes is not altered with dip-coating of polyethylene glycol (PEG)

Heui C. Lee, Janak Gaire, Seth W. Currlin, Matthew D. McDermott, Kinam Park, Kevin J. Otto

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Poly(ethylene glycol) (PEG) is a frequently used polymer for neural implants due to its biocompatible property. As a follow-up to our recent study that used PEG for stiffening flexible neural probes, we have evaluated the biological implications of using devices dip-coated with PEG for chronic neural implants. Mice (wild-type and CX3CR1-GFP) received bilateral implants within the sensorimotor cortex, one hemisphere with a PEG-coated probe and the other with a non-coated probe for 4 weeks. Quantitative analyses were performed using biomarkers for activated microglia/macrophages, astrocytes, blood-brain barrier leakage, and neuronal nuclei to determine the degree of foreign body response (FBR) resulting from the implanted microelectrodes. Despite its well-known acute anti-biofouling property, we observed that PEG-coated devices caused no significantly different FBR compared to non-coated controls at 4 weeks. A repetition using CX3CR1-GFP mice cohort showed similar results. Our histological findings suggest that there is no significant impact of acute delivery of PEG on the FBR in the long-term, and that temporary increase in the device footprint due to the coating of PEG also does not have a significant impact. Large variability seen within the same treatment group also implies that avoiding large superficial vasculature during implantation is not sufficient to minimize inter-animal variability.

Original languageEnglish
Article number513
JournalFrontiers in Neuroscience
Issue numberSEP
StatePublished - Sep 14 2017


  • CX3CR1-GFP
  • Chronic neural implant
  • Foreign body response (FBR)
  • Neuroprosthetics
  • Polyethylene glycol (PEG)


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