High-density stretchable microelectrode array based on multilayer serpentine interconnections

Abstract

Microelectrode array (MEA) is a powerful tool for recording electrophysiological signals and studying the electrophysiological features of nerve, retina, and cardiomyocytes. Stretchable electrodes can form conformal contact with dynamic biological tissues/organs (e.g. heart) to enhance the coupling efficiency in electrophysiological measurements. However, MEAs based on conventional materials require serpentine interconnections to enable stretchability. A large number of serpentine interconnects take up spaces and hinder the improvement of spatial resolution. Here, we introduce a multilayer design strategy that yields a stretchable MEA with spatial density of 7.3 sites/mm2 and biaxial stretchability of 30%. The serpentine interconnects of each layer overlap vertically to reduce the area of the wires used for connection. In vitro validation in phosphate buffered saline (PBS) and ex vivo test on perfused mouse heart show a 100% yield rate of the multilayer stretchable MEA, with capabilities in spatiotemporal mapping of electrophysiological signals at high spatial resolution.

Soft, bioresorbable, transparent microelectrode arrays for multimodal spatiotemporal mapping and modulation of cardiac physiology

“…Similar differences exist in EGs from nonbioresorbable Au microelectrodes (fig. S10) and are reported by other groups (59)(60)(61). These results demonstrate that the bioresorbable and transparent Mo nanogrid MEAs enable in vivo arrhythmia detection, monitoring, and treatment in the beating hearts for cardiac rhythm management (movie S3).…”

Flexible high-density microelectrode arrays for closed-loop brain–machine interfaces: a review

“…Serpentine-shaped metal interconnecting wires were designed to improve the stretchability. Similar serpentine structures were also used in some other latest microsystems ( Ji et al, 2020b ; Xiang et al, 2022 ).…”

“…Serpentine-shaped metal interconnecting wires were designed to improve the stretchability. Similar serpentine structures were also used in some other latest microsystems (Ji et al, 2020b;Xiang et al, 2022). Mesh-like electrode designs have also been explored in order to improve the conformability of HDMEAs to the brain's surface and minimize mechanical stress on cell or tissue.…”

“…However, the development of flexible HDMEAs with these ideal properties entails confronting both the general challenges inherent to HDMEAs and specific challenges unique to their flexible design, encompassing mechanical ( Oldroyd and Malliaras, 2022 ), electrical ( Szostak et al, 2017 ; Qiang et al, 2021 ), biological ( Golabchi et al, 2019 ), chemical ( Shepherd et al, 2021 ), and interconnection issues ( Behfar et al, 2021 ). In response, researchers employ strategies spanning material exploration ( Bonafe, 2022 ; Chik et al, 2022 ), flexible HDMEA design innovation, advanced fabrication strategies ( Scholten et al, 2020 ; Shah et al, 2022 ; Xiang et al, 2022 ), engineering optimization ( Chik et al, 2022 ; Yan et al, 2022 ; Yin et al, 2022 ), and holistic combination strategies ( Eunah et al, 2022 ; Hong et al, 2022 ), aiming to enhance performance and minimize risks in flexible neural interfacing devices.…”

Microstructured Anisotropic Elastomer Composite-Based Vertical Interconnect Access (VIA) for Multilayered Stretchable Electronics

“…Recently, researchers have investigated various unique strategies for forming VIAs at the stretchable substrate, including the patterning of polyimide (PI) at the serpentine metal/PI electrodes; − injection of a metal ink into a textile substrate; direct 3D printing of metals; , drilling holes using a laser and filling metal or liquid metal; − and filling a liquid metal at the microfluidic channel . In the case of using rigid metals as VIAs and electrodes, the stretchability of the entire system can be limited depending on the density of VIAs and electrodes.…”