Flexible and Implantable Microelectrodes for Chronically Stable Neural Interfaces

Abstract

Implantable electrical probes that can record neural activities at single‐neuron and sub‐millisecond resolution are the most widely applied tools in both neuroscience research and neuroprosthetics. However, the structural and mechanical mismatch between conventional rigid probes and neural tissues results in inflammatory responses and signal degradation over chronic recordings. Reducing the cross‐sectional footprints and rigidity of the probes can effectively improve the long‐term stability of neural interfaces. Herein, recent progress in the development of implantable microelectrodes for chronically stable neural interfaces is highlighted, with a focus on the utilization of advanced materials and structural design concepts.

Smart Textile‐Integrated Microelectronic Systems for Wearable Applications

“…Neural probes for the monitoring and interrogation of brain activities have drawn great attention in recent years. To reduce the insertion trauma of the probes, micro/nanoscale fibers are preferred in the construction of neural probes due to their small footprints . The introduction of multifunctional components within a single fiber is enticing, while the assembly of these components is usually costly and labor‐consuming with traditional micro/nanofabrication techniques.…”

Multifunctional Fibers to Shape Future Biomedical Devices

“…Multifunctional fibers are urgently needed in both neuroscience research and neuroprosthetics, in order to record neural activities at a single neuron resolution and communicate with neurons across diverse signal modalities. Thus, these devices have great potentials to treat psychiatric and neurological disorders or to restore functions followed by nerve injury …”

Polymer-based flexible bioelectronics

“…A representative strategy is to modify the structure of the bioelectronic devices by coating soft polymers on rigid electrodes [21,30,36]. For instance, biodegradable poly (lactic-co-glycolic acid) was used as the sacrificial layer or substrate, followed by coating electrodes, interconnects and interlayer dielectrics to produce a transient hydration sensor [7].…”

“…For the use of a flexible device in vitro, it can closely attach on curved skin surface with a stable interface and thus works efficiently under moving [18][19][20]. In the case of the flexible device in vivo, the stable and dynamically matching interfaces between the flexible electronic device and tissues are also found to play a critical role in high biocompatibility [21][22][23]; In contrast, the stiff implants induce astrocytic scars and microglia populations (Fig. 1).…”