title: In vivo Characterization of Amorphous Silicon Carbide As a Biomaterial for Chronic Neural Interfaces.
abstract: Implantable microelectrode arrays (MEAs) offer clinical promise for prosthetic devices by enabling restoration of communication and control of artificial limbs. While proof-of-concept recordings from MEAs have been promising, work in animal models demonstrates that the obtained signals degrade over time. Both material robustness and tissue response are acknowledged to have a role in device lifetime. Amorphous Silicon carbide (a-SiC), a robust material that is corrosion resistant, has emerged as an alternative encapsulation layer for implantable devices. We systematically examined the impact of a-SiC coating on Si probes by immunohistochemical characterization of key markers implicated in tissue-device response. After implantation, we performed device capture immunohistochemical labeling of neurons, astrocytes, and activated microglia/macrophages after 4 and 8 weeks of implantation. Neuron loss and microglia activation were similar between Si and a-SiC coated probes, while tissue implanted with a-SiC displayed a reduction in astrocytes adjacent to the probe. These results suggest that a-SiC has a similar biocompatibility profile as Si, and may be suitable for implantable MEA applications as a hermetic coating to prevent material degradation.
authors.affiliation: Department of Molecular Neuroscience, Krasnow Institute for Advanced Study, George Mason UniversityFairfax, VA, USA; Quantitative Scientific SolutionsArlington, VA, USA.
authors.forename: Gretchen L
authors.initials: GL
authors.lastname: Knaack
authors.affiliation: Department of Molecular Neuroscience, Krasnow Institute for Advanced Study, George Mason University Fairfax, VA, USA.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: McHail
authors.affiliation: Department of Bioengineering, George Mason University Fairfax, VA, USA.
authors.forename: German
authors.initials: G
authors.lastname: Borda
authors.affiliation: Department of Bioengineering, George Mason University Fairfax, VA, USA.
authors.forename: Beomseo
authors.initials: B
authors.lastname: Koo
authors.affiliation: Electrical and Computer Engineering Department, George Mason University Fairfax, VA, USA.
authors.forename: Nathalia
authors.initials: N
authors.lastname: Peixoto
authors.affiliation: Department of Bioengineering, University of Texas at Dallas Richardson, TX, USA.
authors.forename: Stuart F
authors.initials: SF
authors.lastname: Cogan
authors.affiliation: Department of Molecular Neuroscience, Krasnow Institute for Advanced Study, George Mason University Fairfax, VA, USA.
authors.forename: Theodore C
authors.initials: TC
authors.lastname: Dumas
authors.affiliation: Quantitative Scientific SolutionsArlington, VA, USA; Department of Bioengineering, University of Texas at DallasRichardson, TX, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Pancrazio
keywords: amorphous silicon carbide; foreign body response; in vivo models; neural electrode; neuroinflammatory response; neuroprosthetic device