In-plane silicon probes for simultaneous neural recording and drug delivery

Abstract

This paper reports on the design, fabrication and characterization of silicon-based microprobes for simultaneous neural recording and drug delivery. The fabrication technology is based on two-stage deep reactive ion etching combined with silicon wafer bonding and grinding to realize channel structures integrated in needle-like probe shafts. Liquids can be supplied to microfluidic devices via in-plane and out-of-plane ports. The liquid is dispensed at circular out-of-plane ports with a diameter of 25 μm and rectangular in-plane ports with dimensions of 50 × 50 μm 2. Two-shaft probes with a pitch between shafts of 1.0 and 1.5 mm were realized. The probe shafts have a length of 8 mm and rectangular cross-sections of w × h (w = 250 μm and h = 200 or 250 μm). Each shaft contains one or two fluidic channels with a cross-section of 50 × 50 μm 2. In addition, each probe shaft comprises four recording sites with diameters of 20 μm close to the outlet ports. Mechanical and fluidic characterization demonstrated the functionality of the probes. Typical infusion rates of 1.5 μL min −1 are achieved at a differential pressure of 1 kPa. The Pt-gray electrodes have an average electrode impedance of 260 ± 59 k at 1 kHz.

Fabrication and characterization of the flexible neural microprobes with improved structural design

“…Multichannel high-density microprobes have been reported over the past three decades offering advanced capabilities such as three-dimensional (3D) arrays [1,[13][14][15], integrated electronics [16][17][18], integrated biosensors [19,20], and embedded microfluidic channels [21][22][23][24]. Although silicon is the most utilized material [25][26][27][28], other substrates such as metals [29][30][31], sapphire [32], and glass [33] have been employed in the fabrication of microprobes.…”

Prospects for Neuroprosthetics: Flexible Microelectrode Arrays with Polymer Conductors

“…7b) (Colas, 2001;Musick et al, 2009). Various neural implant design studies with included microfluidics have already been reported (e.g., (Metz et al, 2004;Suzuki et al, 2004;Seidl & Et al., 2010)) and their benefit been discussed recently (Musienko et al, 2009). Although the stable coupling of the microchannels to outside fluidics might be possible (e.g., by making use of multilayer bonding concepts (Zhang et al, 2010) or reversible mechanical, pressure-or vacuum-assisted interconnection strategies (Chen & Pan, 2011)), without doubt it will be even more challenging than the design of fail-proof electrical connectors as discussed above.…”

In Vivo Neural Recording and Electrochemical Performance of Microelectrode Arrays Modified by Rough-Surfaced AuPt Alloy Nanoparticles with Nanoporosity

“…With MEMS technology, the precise definition of electrode size and shape can be realized, and multiple recording/stimulation sites can be fabricated on a single probe shank [9]. Starting with the pioneering work from Wise et al [10], a growing number of silicon-based electrode arrays have been developed in the past and the performances of MEMS silicon microelectrodes have been improved in many aspects [11,12], e.g., three-dimensional arrays [13,14,15], dual-sided microelectrode arrays [16], integrated electronics or microfluidic channels [17,18,19,20,21,22], silicon probes for optical stimulation and imaging [23,24,25,26,27,28] or neurochemical signals detection [29,30,31]. In addition, one of the most important fabrication advancements is to integrate a greater number of recording sites on a single probe shank and simultaneously minimizing the probe geometry to avoid large tissue damages during the insertion.…”