Materials and Designs for Multimodal Flexible Neural Probes

Abstract

The use of electrophysiology (EP) signals is the most relevant way to reflect biological activities in cells and tissues. In neuroscience, EP signals are standard indicators enable to display neural activities as action potentials. The action potentials are typically measured by the change of voltage or current from ion channels in the neurons. Usually, conductive electrodes formed on injectable probes that can be penetrated into deep brain tissue for recording EP signals. Over the last few decades, neural probes have been developed using microfabrication technology. Many researchers have attempted to develop and optimize various materials and designs of electrodes and neural probes to effectively minimize their invasive geometry with biocompatible materials. Compared to the rigid and non-flexible neural probes presented in the late 1980s, the shape of deformable neural probes, reported in the late 1990s, has many advantages. A multimodal function (i.e. electric recording with light or drug delivery) for optogenetics technique has also recently been developed as the next generation flexible neural probe. In this chapter, we deal with several examples of flexible neural probes (FNP) in terms of their geometry, materials, and functions. This study will facilitate a new paradigm for less invasive and more flexible multimodal neural probes that can be utilized in many research fields such as materials science, electrical engineering, and fundamental neuroscience.