NeuroMEMS: Neural Probe Microtechnologies

Abstract

Neural probe technologies have already had a significant positive effect on our understanding of the brain by revealing the functioning of networks of biological neurons. Probes are implanted in different areas of the brain to record and/or stimulate specific sites in the brain. Neural probes are currently used in many clinical settings for diagnosis of brain diseases such as seizers, epilepsy, migraine, Alzheimer's, and dementia. We find these devices assisting paralyzed patients by allowing them to operate computers or robots using their neural activity. In recent years, probe technologies were assisted by rapid advancements in microfabrication and microelectronic technologies and thus are enabling highly functional and robust neural probes which are opening new and exciting avenues in neural sciences and brain machine interfaces. With a wide variety of probes that have been designed, fabricated, and tested to date, this review aims to provide an overview of the advances and recent progress in the microfabrication techniques of neural probes. In addition, we aim to highlight the challenges faced in developing and implementing ultra-long multi-site recording probes that are needed to monitor neural activity from deeper regions in the brain. Finally, we review techniques that can improve the biocompatibility of the neural probes to minimize the immune response and encourage neural growth around the electrodes for long term implantation studies.

MEMS electrolytic inchworms for movable neural probe applications

“…A review of MEMS technology for neural probe applications is given by HajjHassan et al [19]. MEMS technology enables accurate and repeatable fabrication of microprobes, and it has the ability to include multiple recording sites on each shank with excellent control over their size and spacing.…”

Prospects for Neuroprosthetics: Flexible Microelectrode Arrays with Polymer Conductors

“…For getting a general overview on in vivo neuroprosthetic 9 implants and brain-machine interfaces including the diverse types of microelectrode arrays, their specific applications and main vendors, the reader shall be referred to recent overview articles and reviews (Hetke & Anderson, 2002;Rutten, 2002;Navarro et al, 2005;Cheung, 2007;Winter et al, 2007;Dowling, 2008;Hajjhassan et al, 2008;Lebedev et al, 2008;Wise et al, 2008;Stieglitz et al, 2009;Graimann et al, 2010;Mussa-Ivaldi et al, 2010;Rothschild, 2010;Hassler et al, 2011). This paragraph will just summarize some of the basic design concepts, general fabrication approaches and the limitations they impose on the performance of chronically implanted devices.…”

Brain machine interfaces combining microelectrode arrays with nanostructured optical biochemical sensors

“…The oxygen sensors are based on quenchometric sensing and use nano-/microporous xerogels to reliably encapsulate the luminophore [Ru(bpy) 3 ] 2+ molecules during the sensor operation. Xerogels are nano-/micro-porous glasses and their appeal for biorecognition elements derives from their thermal stability, tunable pore dimensions and distributions, biocompatibility, and a broad optical transparency window [12].…”

“…In addition, the probes should incorporate sufficient mechanical strength to survive the compression and tensile forces during the insertion and retraction phases respectively while implantation into the brain. NeuroMEMS, or silicon-based neural probes allow the fabrication of long, miniaturized and well defined probes carrying accurately spaced recording sites thus fulfilling the requirements mentioned above [3].…”