Electro-optical mechanically flexible coaxial microprobes for minimally invasive interfacing with intrinsic neural circuits

Abstract

Central to advancing our understanding of neural circuits is developing minimally invasive, multi-modal interfaces capable of simultaneously recording and modulating neural activity. Recent devices have focused on matching the mechanical compliance of tissue to reduce inflammatory responses. However, reductions in the size of multi-modal interfaces are needed to further improve biocompatibility and long-term recording capabilities. Here a multi-modal coaxial microprobe design with a minimally invasive footprint (8–14 µm diameter over millimeter lengths) that enables efficient electrical and optical interrogation of neural networks is presented. In the brain, the probes allowed robust electrical measurement and optogenetic stimulation. Scalable fabrication strategies can be used with various electrical and optical materials, making the probes highly customizable to experimental requirements, including length, diameter, and mechanical properties. Given their negligible inflammatory response, these probes promise to enable a new generation of readily tunable multi-modal devices for long-term, minimally invasive interfacing with neural circuits.

Electron Conductive and Transparent Hydrogels for Recording Brain Neural Signals and Neuromodulation

“…[27,28] The flexible probes can be prepared by depositing a thin metal or metal oxide layer on a polymer substrate or composites of flexible polymers with carbon materials or conductive polymers. [29][30][31][32] Although the literature has reported flexible sensors with a modulus of below 100 MPa, they are still much more rigid compared to neural tissues. [33,34] To resolve the issue of mechanical property mismatch between implantable materials and neural tissues, hydrogels have attracted attention due to their excellent biocompatibility.…”

A self-stiffening compliant intracortical microprobe

“…Neural microprobes contribute significantly to the study of brain function, brain diseases, and brain-machine interfaces (Li et al 2023 ; McGlynn et al 2022 ; Ward et al 2022 ). An intracortical microprobe needs to be implanted deep within the brain to directly interface with specific brain regions allowing for high-accuracy brain recording and stimulation (Atkinson et al 2021 ; Zhou et al 2023 ).…”

Soft Bioelectronics Using Nanomaterials and Nanostructures for Neuroengineering

“…In addition to enhancing the spatiotemporal resolution and mechanical compliance, multifunctionality (e.g., optical, chemical, and electrical functions) can be imparted to bioelectronics using nanomaterials. For example, light-emitting devices based on nanomaterials can manipulate genetically modified cells 22,23 (Figure 1b). The release of nanoscale drugs and neurotransmitters can be controlled in response to real-time monitoring of local biochemical concentrations and biophysical conditions in unified soft bioelectronics.…”

“…In addition to enhancing the spatiotemporal resolution and mechanical compliance, multifunctionality (e.g., optical, chemical, and electrical functions) can be imparted to bioelectronics using nanomaterials. For example, light-emitting devices based on nanomaterials can manipulate genetically modified cells , (Figure b). The release of nanoscale drugs and neurotransmitters can be controlled in response to real-time monitoring of local biochemical concentrations and biophysical conditions in unified soft bioelectronics. ,, Moreover, soft nanobioelectrodes can achieve the accurate sensing of electrophysiological signals and precise electrical stimulation − and high-quality bidirectional communication with neural networks using various modalities, which is useful for improving the treatment efficacy of several neurological disorders, such as brain tumors, epilepsy, and Parkinson’s disease (PD).…”