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

Abstract

Ultraflexible neural probe is an ideal tool for brain research, which can reduce the mechanical interfacial mismatch between electrodes and brain tissue and can thus reduce the tissue's inflammation and extend the electrodes' service life. However, the low stiffness of ultraflexible neural probe makes it susceptible to bending and buckling during insertion into brain. Here, a simple yet robust design of removable insertion shuttle consisting of a steel needle with a dissolvable spheroid micropost is reported for ultraflexible neural probe implantation. The dissolvable spheroid micropost of insertion shuttle is fabricated by the simple dip‐coating process based on the competition and balance between the surface tension and gravity. A temporary engaging mechanism enabled by the micropost engaged into the via hole on the tip of ultraflexible neural probe is adopted to enable an easy and quick implantation. Experimental studies reveal the fundamental aspects of the design of removable insertion shuttle and the operation of implantation. In vivo implantation of ultraflexible neural probes into rat's brain illustrates the unusual capabilities of removable insertion shuttle with the accurate positioning of probe at desired depth and the stable chronic brain electrophysiological recording, which show great potential in both basic neuroscience and clinical applications.

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

“…A second method to temporarily attach shuttles to stiff carriers is by using a so called needle-and-thread approach [ 74 , 82 , 195 ] ( Figure 6 e,f). In this approach the probe functions as the needle and a stiff microwire [ 74 ] or even an actual needle [ 195 ] can function as the thread. For this method to work, the implantable probes have to incorporate a small hole at the probe tip.…”

Unconventional Device and Material Approaches for Monolithic Biointegration of Implantable Sensors and Wearable Electronics

“…Due to the recent advances in techniques for designing such materials and devices, the electronic devices now feature unprecedented soft mechanical properties that are similar to those of human tissues. [ 1–7 ] This has led to the developments in implantable biosensors and wearable bioelectronics, thereby enabling their monolithic biointegration with target tissues.…”

Development of a Polydimethylsiloxane‐Based Electrode Array for Electrocorticography

“…[ 39 ] Several interfaces utilized the biodegradable materials such as polyvinyl alcohol, polyethylene glycol, or silk to harden ultrathin devices instantly for implantation. [ 21,41,42 ]…”

“…In other words, the substrates made up of polyimide or parylene‐C, relatively rigid materials, can overcome their natural rigidity by reducing the thickness, but the ultrathin substrate of neural interfaces necessitates an extra guiding or supporting structure. [ 21,41,42 ] In case of neural interfaces based on bioresorbable materials, the devices are limited only to short‐term implantation. In addition, insufficient in vivo data to demonstrate the biocompatibility [ 43 ] and uncontrollable demise hinder the bioelectronic devices made up of these innovative materials.…”