Printed microelectrode arrays on soft materials: from PDMS to hydrogels

Abstract

Microelectrode arrays (MEAs) provide promising opportunities to study electrical signals in neuronal and cardiac cell networks, restore sensory function, or treat disorders of the nervous system. Nevertheless, most of the currently investigated devices rely on silicon or polymer materials, which neither physically mimic nor mechanically match the structure of living tissue, causing inflammatory response or loss of functionality. Here, we present a new method for developing soft MEAs as bioelectronic interfaces. The functional structures are directly deposited on PDMS-, agarose-, and gelatin-based substrates using ink-jet printing as a patterning tool. We demonstrate the versatility of this approach by printing high-resolution carbon MEAs on PDMS and hydrogels. The soft MEAs are used for in vitro extracellular recording of action potentials from cardiomyocyte-like HL-1 cells. Our results represent an important step toward the design of next-generation bioelectronic interfaces in a rapid prototyping approach.npj Flexible Electronics (2018) 2:15 ;

Optimization of makerspace microfabrication techniques and materials for the realization of planar, 3D printed microelectrode arrays in under four days

“…So MEAs directly deposited on PDMS-, agarose-, and gelatin-based substrates using ink-jet printing as a patterning tool has been demonstrated for in vitro extracellular recording of action potentials from cardiomyocyte-like HL-1 cells which represents an important step toward the design of next-generation bioelectronic interfaces in a rapid prototyping approach. 19 Single substrate interfacing approaches wherein so devices, such as sensors, are directly printed on Kapton® substrates that are widely used for fabricating exible printed circuit boards (FPCBs) have additionally been demonstrated for interfacing so and hard electronics for health and performance monitoring, as well as internet of things applications. 20 Makerspace fabrication is another alternative environment to cleanroom fabrication and involves lower cost equipment, materials and faster turnaround times.…”

“…25 This resolution can be competitive with other makerspace fabrication methods such as inkjet printed MEA. 19,26 With 3D PICLmM, a 3D printed MEA with an electrode density of 3 Â 3 was previously demonstrated as a proof of concept. 22 Optimizing the design, process and materials of this 3D PICLmM approach would allow for a desired end product of a transparent, high density, single well MEA that could be "used and tossed" during research.…”

Flexible Nanoporous Gold Electrodes for Electroanalysis in Complex Matrices

“…[30,34] As with glass substrates, the attachment of gold to PDMS often utilizes a linker molecule such as 3-mercaptopropyltrimethoxysilane. [25][26]29,35] In the present work, we show that high surface area NPG can be interfaced to PDMS without the use of linker molecules. More noteworthy, we also show the promise such flexible electrodes have for electrochemical sensing in samples with a complex matrix such as blood.…”

Printable microscale interfaces for long-term peripheral nerve mapping and precision control

“…High-resolution 3D printing offers the possibility of orthogonalizing the mechanical and material properties of an object, such that pliable microscale structures can be created from materials that are otherwise stiff and rigid (Bückmann et al, 2012(Bückmann et al, , 2014. This decoupling is evident in the nanoclip's elastically-deformable hinges (Figure 1) despite the Young's modulus of their bulk material being within the gigapascal range (Meza et al, 2015), and additional investigation of metamaterial designs that mimic the biomechanics of peripheral tissues could significantly improve long-term biointegration of these devices (Adly et al, 2018;Minev et al, 2015). Additionally, the integration of non-planar electrode arrays that provide improved electrical access to the nerve -either by increasing efficacy of contact with the epineurim (Robinson et al, 2012;Shmoel et al, 2016) or by penetrating into the intraneural space (Angle et al, 2015;Gillis et al, 2018;Vitale et al, 2015) -may allow for greater recording and stimulating specificity with low risk of increased host tissue trauma (Salatino et al, 2017).…”