Concurrent recordings of bladder afferents from multiple nerves using a microfabricated PDMS microchannel electrode array

In this paper we present a compliant neural interface designed to record bladder afferent activity. We developed the implant's microfabrication process using multiple layers of silicone rubber and thin metal so that a gold microelectrode array is embedded within four parallel polydimethylsiloxa...

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Bibliographic Details
Published in:Lab on a chip 2012-07, Vol.12 (14), p.2540-2551
Main Authors: Delivopoulos, Evangelos, Chew, Daniel J, Minev, Ivan R, Fawcett, James W, Lacour, Stéphanie P
Format: Article
Language:English
Subjects:
Animals
Dielectric Spectroscopy - instrumentation
Dielectric Spectroscopy - methods
Dimethylpolysiloxanes - chemistry
Electric Impedance
Female
Microelectrodes
Porosity
Rats
Rats, Sprague-Dawley
Spinal Nerve Roots - physiology
Urinary Bladder - physiology
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Summary:In this paper we present a compliant neural interface designed to record bladder afferent activity. We developed the implant's microfabrication process using multiple layers of silicone rubber and thin metal so that a gold microelectrode array is embedded within four parallel polydimethylsiloxane (PDMS) microchannels (5 mm long, 100 μm wide, 100 μm deep). Electrode impedance at 1 kHz was optimized using a reactive ion etching (RIE) step, which increased the porosity of the electrode surface. The electrodes did not deteriorate after a 3 month immersion in phosphate buffered saline (PBS) at 37 °C. Due to the unique microscopic topography of the metal film on PDMS, the electrodes are extremely compliant and can withstand handling during implantation (twisting and bending) without electrical failure. The device was transplanted acutely to anaesthetized rats, and strands of the dorsal branch of roots L6 and S1 were surgically teased and inserted in three microchannels under saline immersion to allow for simultaneous in vivo recordings in an acute setting. We utilized a tripole electrode configuration to maintain background noise low and improve the signal to noise ratio. The device could distinguish two types of afferent nerve activity related to increasing bladder filling and contraction. To our knowledge, this is the first report of multichannel recordings of bladder afferent activity.
ISSN:1473-0197
1473-0189
DOI:10.1039/c2lc21277c