Spatially expandable fiber-based probes as a multifunctional deep brain interface

Abstract

Understanding the cytoarchitecture and wiring of the brain requires improved methods to record and stimulate large groups of neurons with cellular specificity. This requires miniaturized neural interfaces that integrate into brain tissue without altering its properties. Existing neural interface technologies have been shown to provide high-resolution electrophysiological recording with high signal-to-noise ratio. However, with single implantation, the physical properties of these devices limit their access to one, small brain region. To overcome this limitation, we developed a platform that provides three-dimensional coverage of brain tissue through multisite multifunctional fiber-based neural probes guided in a helical scaffold. Chronic recordings from the spatially expandable fiber probes demonstrate the ability of these fiber probes capturing brain activities with a single-unit resolution for long observation times. Furthermore, using Thy1-ChR2-YFP mice we demonstrate the application of our probes in simultaneous recording and optical/chemical modulation of brain activities across distant regions. Similarly, varying electrographic brain activities from different brain regions were detected by our customizable probes in a mouse model of epilepsy, suggesting the potential of using these probes for the investigation of brain disorders such as epilepsy. Ultimately, this technique enables three-dimensional manipulation and mapping of brain activities across distant regions in the deep brain with minimal tissue damage, which can bring new insights for deciphering complex brain functions and dynamics in the near future.

Thermally drawn multifunctional fibers: Toward the next generation of information technology

“…Some advanced neural probes have been developed to promote the development of optogenetics and understanding of the nervous system. For example, Jiang et al prepared a multisite neural probe that provides 3D records of brain tissue when introduced into the brain at different specific angles by designing hollow helix channels, as shown in Figure 8J 111 . Lu et al reported a bendable and stretchable spinal probe to meet repeated deformation of the spine during normal movement.…”

“…The insert shows a cross‐sectional image of the scaffolding fiber containing seven hollow channels. Reproduced with permission 111 . Copyright 2020, Springer Nature.…”

“…For example, Jiang et al prepared a multisite neural probe that provides 3D records of brain tissue when introduced into the brain at different specific angles by designing hollow helix channels, as shown in Figure 8J. 111 Lu et al reported a bendable and stretchable F I G U R E 8 (A) Cross-sectional image of the all-polymer neural probe. Reproduced with permission.…”

Multimodal neural probes for combined optogenetics and electrophysiology

“…To achieve synchronous recording and modulation of brain activities across multiple brain regions, Jiang et al fabricated a spatially expandable multifunctional fiber probe by TDP technique (Jiang et al, 2020). Multifunctional fibers, consisting of an optical waveguide, microfluidic channels, and BiSn metal alloy electrodes, were firstly fabricated using the TDP process (Figure 5I).…”

“…Continued (L) An illustration of a spatially expanded multimodal fiber probe targeting the thalamus region and a photograph of the assembled device coupled to the 473 nm laser (left), and the electrophysiological recording resulted from 5 electrodes during optogenetic stimulation (right). Panels I to L are reproduced fromJiang et al (2020).…”