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. APPROACH: 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. MAIN 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. SIGNIFICANCE: Overall, the data show strikingly that mechanically-compliant intracortical implants can reduce the neuroinflammatory response in comparison to stiffer systems.
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. APPROACH: 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. MAIN 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. SIGNIFICANCE: Overall, the data show strikingly that mechanically-compliant intracortical implants can reduce the neuroinflammatory response in comparison to stiffer systems.
Authors: Cort H Thompson; Ti'Air E Riggins; Paras R Patel; Cynthia A Chestek; Wen Li; Erin Purcell Journal: J Neural Eng Date: 2020-03-12 Impact factor: 5.379
Authors: Kyung Nim Noh; Sung Il Park; Raza Qazi; Zhanan Zou; Aaron D Mickle; Jose G Grajales-Reyes; Kyung-In Jang; Robert W Gereau; Jianliang Xiao; John A Rogers; Jae-Woong Jeong Journal: Small Date: 2017-12-07 Impact factor: 13.281
Authors: John K Hermann; Madhumitha Ravikumar; Andrew J Shoffstall; Evon S Ereifej; Kyle M Kovach; Jeremy Chang; Arielle Soffer; Chun Wong; Vishnupriya Srivastava; Patrick Smith; Grace Protasiewicz; Jingle Jiang; Stephen M Selkirk; Robert H Miller; Steven Sidik; Nicholas P Ziats; Dawn M Taylor; Jeffrey R Capadona Journal: J Neural Eng Date: 2018-04 Impact factor: 5.379
Authors: Morgan B Lee; Daniel R Kramer; Terrance Peng; Michael F Barbaro; Charles Y Liu; Spencer Kellis; Brian Lee Journal: J Clin Neurosci Date: 2019-07-30 Impact factor: 1.961