Mechanically Robust, Softening Shape Memory Polymer Probes for Intracortical Recording.

While intracortical microelectrode arrays (MEAs) may be useful in a variety of basic and clinical scenarios, their implementation is hindered by a variety of factors, many of which are related to the stiff material composition of the device. MEAs are often fabricated from high modulus materials such as silicon, leaving devices vulnerable to brittle fracture and thus complicating device fabrication and handling. For this reason, polymer-based devices are being heavily investigated; however, their implementation is often difficult due to mechanical instability that requires insertion aids during implantation.

Deployable, liquid crystal elastomer-based intracortical probes.

Intracortical microelectrode arrays (MEAs) are currently limited in their chronic functionality due partially to the foreign body response (FBR) that develops in regions immediately surrounding the implant (typically within 50-100 µm). Mechanically flexible, polymer-based substrates have recently been explored for MEAs as a way of minimizing the FBR caused by the chronic implantation. Nonetheless, the FBR degrades the ability of the device to record neural activity.

Mechanical considerations for design and implementation of peripheral intraneural devices.

Objective: Neural interfaces designed to stimulate or record electrical activity from peripheral nerves have applications ranging from the electrical modulation of nerve activity as a therapeutic option (e.g. epilepsy and depression) to the design of prosthetics.

Electrical Properties of Thiol-ene-based Shape Memory Polymers Intended for Flexible Electronics.

Thiol-ene/acrylate-based shape memory polymers (SMPs) with tunable mechanical and thermomechanical properties are promising substrate materials for flexible electronics applications. These UV-curable polymer compositions can easily be polymerized onto pre-fabricated electronic components and can be molded into desired geometries to provide a shape-changing behavior or a tunable softness. Alternatively, SMPs may be prepared as a flat substrate, and electronic circuitry may be built directly on top by thin film processing technologies.

Chronic Intracortical Recording and Electrochemical Stability of Thiol-ene/Acrylate Shape Memory Polymer Electrode Arrays.

Current intracortical probe technology is limited in clinical implementation due to the short functional lifetime of implanted devices. Devices often fail several months to years post-implantation, likely due to the chronic immune response characterized by glial scarring and neuronal dieback. It has been demonstrated that this neuroinflammatory response is influenced by the mechanical mismatch between stiff devices and the soft brain tissue, spurring interest in the use of softer polymer materials for probe encapsulation.

A Meta-Analysis of Intracortical Device Stiffness and Its Correlation with Histological Outcomes.

Neural implants offer solutions for a variety of clinical issues. While commercially available devices can record neural signals for short time periods, they fail to do so chronically, partially due to the sustained tissue response around the device. Our objective was to assess the correlation between device stiffness, a function of both material modulus and cross-sectional area, and the severity of immune response.

A Mosquito Inspired Strategy to Implant Microprobes into the Brain.

Mosquitos are among the deadliest insects on the planet due to their ability to transmit diseases like malaria through their bite. In order to bite, a mosquito must insert a set of micro-sized needles through the skin to reach vascular structures. The mosquito uses a combination of mechanisms including an insertion guide to enable it to bite and feed off of larger animals.

Thinking Small: Progress on Microscale Neurostimulation Technology.

Objectives: Neural stimulation is well-accepted as an effective therapy for a wide range of neurological disorders. While the scale of clinical devices is relatively large, translational, and pilot clinical applications are underway for microelectrode-based systems. Microelectrodes have the advantage of stimulating a relatively small tissue volume which may improve selectivity of therapeutic stimuli.