Electroplated Nickel Multielectrode Microprobes With Flexible Parylene Cable for Neural Recording and Stimulation

Abstract

We design, fabricate, and characterize nickel-based multielectrode microprobes integrated with flexible parylene cable employing low-cost nickel electroplating process, intended for multichannel recording and stimulation of neurons in the brain. Electroplated nickel microprobes, which are encapsulated with parylene for biocompatibility, are more mechanically robust than brittle silicon-based ones. The selectively integrated flexible parylene cable facilitates the connection with external circuits and reduces the packaging requirements. The mechanical and electrical characterizations have been performed. Using the microprobes, the spontaneous neural activity in rat's hippocampus is recorded and the wing beat of tethered worker honeybees is initiated by delivering the stimulating pulse into the optic lobes.[2012-0372]

A Removable Insertion Shuttle for Ultraflexible Neural Probe Implantation with Stable Chronic Brain Electrophysiological Recording

“…The impedance of electrode decreases with the increase of frequency. The measured impedance of electrode at the biologically relevant frequency of 1 kHz is 52.4 kΩ, which is comparable with Au electrode in references …”

“…However, the low stiffness of flexible neural probe makes it susceptible to bending and buckling during insertion into the brain. To deal with this dilemma, several delicate strategies have been developed to guide the insertion such as transient shuttles with dissolvable support materials such as silk, sugars, hydrogel or polyethylene glycol (PEG) as coatings, metal as rigid backbone layers for insertion, and removable shuttles with SU‐8 shanks or microneedles as temporary carriers. To remove the need of additional materials that may displace tissue in shuttle strategies, mechanically adaptive materials that change modulus on exposure to physiological conditions have been utilized as the probe substrates despite the potential biocompatibility issue.…”

SF6 Optimized O2 Plasma Etching of Parylene C

“…Parylene C, or poly(monochloro-p-xylylene), is one of the most-used polymer materials in MEMS (micro-electro-mechanical system) for its compatibility with microfabrication techniques and excellent material properties. It is a chemically stable, USP (United States Pharmacopeia) Class VI biocompatible, and flexible material that has been widely implemented in microfluidics and bioMEMS applications such as microvalves [ 1 ], accelerometers [ 2 ], flexible electrodes [ 3 , 4 ], and neural probes [ 5 , 6 , 7 ]. To pattern the Parylene C, different fabrication techniques have been proposed, such as wet etching using chloronapthelene or benzoyl benzoate [ 8 ], dry etching based on O 2 plasma [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], thermal imprinting or micro-molding [ 16 , 17 ] and laser micromachining [ 18 , 19 , 20 ].…”

Highly controllable and reliable ultra-thin Parylene deposition

“…As one of the most widely-used polymers in the microelectromechanical system (MEMS), Parylene played active roles in flexible electronics and biomedical microdevices, such as substrates for flexible microelectrode array [1][2][3], protection layer for microdevices [4][5][6][7][8][9], etc. Generally, the Parylene deposition process consists of three steps: (1) Parylene dimers were vaporized in the sublimation furnace at temperature of 150-175 °C.…”

“…Generally, the Parylene deposition process consists of three steps: (1) Parylene dimers were vaporized in the sublimation furnace at temperature of 150-175 °C. (2) The vaporized dimers were then pyrolyzed into monomers in the hightemperature (~690 °C) furnace. (3) The monomers then entered the machine chamber and deposited onto the exposed substrates at room temperature.…”