Enhanced biocompatibility of neural probes by integrating microstructures and delivering anti-inflammatory agents via microfluidic channels.
Biocompatibility is a major issue for chronic neural implants, involving inflammatory and wound healing responses of neurons and glial cells. To enhance biocompatibility, we developed silicon-parylene hybrid neural probes with open architecture electrodes, microfluidic channels and a reservoir for drug delivery to suppress tissue responses.



We chronically implanted our neural probes in the rat auditory cortex and investigated (1) whether open architecture electrode reduces inflammatory reaction by measuring glial responses; and (2) whether delivery of antibiotic minocycline reduces inflammatory and tissue reaction. Four weeks after implantation, immunostaining for glial fibrillary acid protein (astrocyte marker) and ionizing calcium-binding adaptor molecule 1 (macrophages/microglia cell marker) were conducted to identify immunoreactive astrocyte and microglial cells, and to determine the extent of astrocytes and microglial cell reaction/activation. A comparison was made between using traditional solid-surface electrodes and newly-designed electrodes with open architecture, as well as between deliveries of minocycline and artificial cerebral-spinal fluid diffused through microfluidic channels.



The new probes with integrated micro-structures induced minimal tissue reaction compared to traditional electrodes at 4 weeks after implantation. Microcycline delivered through integrated microfluidic channels reduced tissue response as indicated by decreased microglial reaction around the neural probes implanted.



The new design will help enhance the long-term stability of the implantable devices.
Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, MI, United States of America.
Bin
B
Liu
Eric
E
Kim
Anika
A
Meggo
Sachin
S
Gandhi
Hao
H
Luo
Srinivas
S
Kallakuri
Yong
Y
Xu
Jinsheng
J
Zhang
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001303:Auditory Cortex / Q000187:drug effects / Q000276:immunology*; D004343:Drug Implants / Q000008:administration & dosage*; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004660:Encephalitis / Q000209:etiology / Q000276:immunology* / Q000517:prevention & control*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018511:Systems Integration; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D004343:Drug Implants