A novel dexamethasone-releasing, anti-inflammatory coating for neural implants

Y. Zhong, G. C. McConnell, J. D. Ross, S. P. Deweerth, R. V. Bellamkonda

Research output: Contribution to conferencePaperpeer-review

35 Scopus citations

Abstract

The long-term stability of implanted micromachined neural probes is compromised due to the glial scar formation at the insertion site. In this study, we developed a novel nitrocellulose-based coating for the sustained local delivery of the anti-inflammatory drug dexamethasone, a synthetic glucocorticoid that effectively reduces inflammation in the CNS. In vitro dexamethasone release was observed over 16 days, with a relatively high release in the first three days and a slow, stable release thereafter. When Michigan neural recording probes coated with and without dexamethasone-loaded nitrocellulose coatings were implanted into the adult rat brains, immunohistochemical evidence shows a marked reduction of reactive astrocytes (GFAP), reactive microglia (ED1), and chondroitin sulfate proteoglycans (CS56) expression around the insertion site compared to uncoated probes. Impedance spectroscopy showed that the dexamethasone-loaded nitrocellulose coatings slightly reduce the magnitude of electrode impedance at the biologically relevant frequency of 1 kHz through an increase of capacitance. In vivo acute recordings demonstrate that extracellular recordings with coated probes are akin to non-coated probes and it is anticipated that with time, the coated probes will exhibit superior performance. In conclusion, we developed a novel nitrocellulose-based, drug releasing coating for neural electrodes that can effectively reduce scar tissue formation without adversely affecting the electrical performance of the electrodes.

Original languageEnglish
Pages522-525
Number of pages4
DOIs
StatePublished - 2005
Event2nd International IEEE EMBS Conference on Neural Engineering, 2005 - Arlington, VA, United States
Duration: 16 Mar 200519 Mar 2005

Conference

Conference2nd International IEEE EMBS Conference on Neural Engineering, 2005
Country/TerritoryUnited States
CityArlington, VA
Period16/03/0519/03/05

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