Multishank Thin‐Film Neural Probes and Implantation System for High‐Resolution Neural Recording Applications

Abstract

Silicon probes have played a key role in studying the brain. However, the stark mechanical mismatch between these probes and the brain leads to chronic damage in the surrounding neural tissue, limiting their application in research and clinical translation. Mechanically flexible probes made of thin plastic shanks offer an attractive tissue-compatible alternative but are difficult to implant into the brain and struggle to achieve the electrode density and layout necessary for the high-resolution applications their silicon counterparts excel at. Here, we present a multi-shank high-density flexible neural probe design which emulates the functionality of stiff silicon arrays for neural population recordings across multiple sites within a given region. The flexible probe is accompanied by a detachable 3D printed implanter which delivers the probe by means of hydrophobic-coated shuttles. The shuttles can then be retracted with minimal movement, and the implanter houses the electronics necessary for in vivo recording applications. Validation of the probes through extracellular recordings from multiple brain regions and histological evidence of minimal foreign body response opens the path to long-term chronic monitoring of neural ensembles.

Tuning the Physically Induced Crystallinity of Microfabricated Bioresorbable Guides for Insertion of Flexible Neural Implants

“…The significant stiffness improvement in c‐PVA is further quantified using an insertion test with a universal mechanical testing machine into a PDMS membrane, mimicking rat dura mater as the closest animal model. [ 8 ] Most of the surgical protocols for implanting neural probes require the removal of the dura mater. This membrane is relatively thick and limits the penetration of low mechanical modulus polymer‐based devices.…”

“…This membrane is relatively thick and limits the penetration of low mechanical modulus polymer‐based devices. [ 8 ] This makes surgery and animal recovery even more challenging as it raises the risk of bleeding and infection. Herein, we measure the penetrability of shanks in PDMS film with a thickness of 50 µm as an evaluation model.…”

“…Shank Insertion Test: The artificial dura mater was made of polydimethylsiloxane (PDMS), as described in the literature. [8] First, elastomer and curing agent with the ratio of 10:1 (PDMS, Sylgard 184, Elseworth adhesives) were mixed together. The PDMS was spin-coated on a glass slide at a speed of 1000 rpm for a duration of 60 s and dried for 5 min at 100 °C.…”

“…The fabrication of such devices is based on the use of polymers such as parylene-C (Pa-C), polyimide, polydimethylsiloxane (PDMS), various hydrogels, or other much thinner stiff materials. [8][9][10][11][12][13] Their performance in brain-machine interfaces has been demonstrated for over a decade. Although several device prototypes made of plastic electronics are mechanically minimally invasive and trace the future of neural implants, they are unable to reliably penetrate brain tissue.…”

Electrodeposition of PEDOT:ClO4 on non-noble tungsten microwire for nerve and brain recordings

“…For brain implantation, brain maps were used to locate the middle area of the barrel cortex where the microwires were inserted following a technique published elsewhere. 68 The barrel cortex is located in the primary somatosensory cortex, which is located in the postcentral gyrus of the parietal lobes. After shaving it, the head of the animal was fixed on a stereotaxic frame.…”