Implantable Neural Probe System for Patterned Photostimulation and Electrophysiology Recording

Abstract

We demonstrate a system for implantable nanophotonic neural probes with custom packaging and peripherals. The probes, which were manufactured on 200mm Si wafers, monolithically integrate SiN waveguides with TiN electrophysiology electrodes and were tested in vivo.

Development of wafer-scale multifunctional nanophotonic neural probes for brain activity mapping

“…In addition to the single SiN waveguide layer, 3 metal routing layers and TiN surface electrodes are integrated to realize electrophysiological recording with the probe. 52,55 Microfluidic channels can also be printed on the probe, allowing neurochemical drug delivery to the brain. 56 external laser is deflected to each core in the MCF using a MEMS mirror-based laser scanning system.…”

“…The output power variation across the emitters on the probe packaged with the machine was within 5.3 dB for 3 packaged probes. 55 To reduce the optical insertion loss caused by the misalignment of the MCF-to-chip interface during packaging, the probe shanks can be selectively thinned to preserve a thicker base for the edge couplers, 64 and a V-groove can be cut in the probe holders to increase the fiber attachment stability. Using grating couplers instead of edge couplers can improve packaging reliability due to larger bonding surface area and greater tolerance for displacement caused by epoxy shrinkage.…”

“…53,54 The probes are fabricated in a commercial foundry (Advanced Micro Foundry), and hundreds to more than a thousand probes fit on a 200 mm diameter Si wafer. The probes combine waveguides and electrodes, 52,55 and microfluidic channels can be 3D printed onto the probes. 56 This versatile platform lays the foundation for multifunctional neural probes for multimodal exploration of neural circuits.…”

“…aOnly report the cross-sectional area of a single shank unless specified otherwise.bWe have demonstrated emitters with various beam characteristics utilizing a single-layer SiN waveguide, including low-divergence beams, light sheets, steerable beams, and focusing beams. 46–52 cCross-sectional area of a silicon shank + a 3D printed microfluidic channel.dRef. 47–50 reported with wavelength operation at 488 nm and ref.…”

“…Fig.7(a) Cross-sectional illustration of the multi-modal neural probe. In addition to the single SiN waveguide layer, 3 metal routing layers and TiN surface electrodes are integrated to realize electrophysiological recording with the probe 52,55. Microfluidic channels can also be printed on the probe, allowing neurochemical drug delivery to the brain 56.…”