title: Mechanically-compliant intracortical implants reduce the neuroinflammatory response.
abstract: OBJECTIVE
  The mechanisms underlying intracortical microelectrode encapsulation and failure are not well understood. A leading hypothesis implicates the role of the mechanical mismatch between rigid implant materials and the much softer brain tissue. Previous work has established the benefits of compliant materials on reducing early neuroinflammatory events. However, recent studies established late onset of a disease-like neurodegenerative state.
  
  
  METHODS
  In this study, we implanted mechanically-adaptive materials, which are initially rigid but become compliant after implantation, to investigate the long-term chronic neuroinflammatory response to compliant intracortical microelectrodes.
  
  
  RESULTS
  Three days after implantation, during the acute healing phase of the response, the tissue response to the compliant implants was statistically similar to that of chemically matched stiff implants with much higher rigidity. However, at two, eight, and sixteen weeks post-implantation in the rat cortex, the compliant implants demonstrated a significantly reduced neuroinflammatory response when compared to stiff reference materials. Chronically implanted compliant materials also exhibited a more stable blood-brain barrier than the stiff reference materials.
  
  
  CONCLUSIONS
  Overall, the data show strikingly that mechanically-compliant intracortical implants can reduce the neuroinflammatory response in comparison to stiffer systems.
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, 2071 Martin Luther King Jr Drive, Wickenden Bldg, Cleveland, OH 44106, USA. Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Blvd, 151W/APT, Cleveland, OH 44106-1702, USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Nguyen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Park
authors.forename: John L
authors.initials: JL
authors.lastname: Skousen
authors.forename: Allison E
authors.initials: AE
authors.lastname: Hess-Dunning
authors.forename: Dustin J
authors.initials: DJ
authors.lastname: Tyler
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Rowan
authors.forename: Christoph
authors.initials: C
authors.lastname: Weder
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Capadona
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000009:adverse effects*; D017076:Computer-Aided Design; D004548:Elasticity; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004660:Encephalitis / Q000209:etiology* / Q000473:pathology* / Q000517:prevention & control; D019544:Equipment Failure Analysis; D008297:Male; D008422:Materials Testing; D008839:Microelectrodes / Q000009:adverse effects*; D011474:Prosthesis Design; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D020099:Coated Materials, Biocompatible