Aerosol Jet-Printed High-Aspect Ratio Micro-Needle Electrode Arrays Applied for Human Cerebral Organoids and 3D Neurospheroid Networks

Abstract

The human brain is a complex and poorly accessible organ. Thus, new tools are required for studying the neural function in a controllable environment that preserves multicellular interaction and neuronal wiring. In particular, high-throughput methods that alleviate the need for animal experiments are essential for future studies. Recent developments of induced pluripotent stem cell technologies have enabled in vitro modeling of the human brain by creating three-dimensional brain tissue mimic structures. To leverage these new technologies, a systematic and versatile approach for evaluating neuronal activity at larger tissue depths within the regime of tens to hundreds of micrometers is required. Here, we present an aerosol-jet- and inkjet-printing-based method to fabricate microelectrode arrays, equipped with high-aspect ratio μ-needle electrodes that penetrate 3D neural network assemblies. The arrays have been successfully applied for electrophysiological recordings on interconnected neurospheroids formed on an engineered substrate and on cerebral organoids, both derived from human induced pluripotent stem cells.

Engineering biomaterials by inkjet printing of hydrogels with functional particulates

“…Inkjet printing technology has shown significant promise in the fabrication of organoids and spheroids, which are the most basic tissue models in tissue engineering. The ability of inkjet printing to precisely deposit cells and biomaterials layer by layer allows for the creation of complex, three-dimensional structures that closely mimic the architecture of natural organs [ 60 ]. This precision is crucial for developing organoids and spheroids with specific cellular compositions and spatial arrangements, which are essential for replicating the function of native tissues.…”

Decellularized Brain Extracellular Matrix Hydrogel Aids the Formation of Human Spinal-Cord Organoids Recapitulating the Complex Three-Dimensional Organization

“…The spinal cord’s intricate anatomical structure and physiological function lead to complex pathophysiological response postinjury, making it extremely challenging to simulate post-SCI microenvironment ex vivo . , Furthermore, many drugs that prove effective in animal studies on spinal cord injuries do not benefit humans . Due to ethical concerns, it is difficult to obtain spinal cord tissue from humans .…”

Three-Dimensional Morphology and Contour Quality of Conductive Lines Printed by High-Viscosity Paste Jetting

“…Materials with good electrical conductivity typically exhibit higher viscosities; therefore, the printing methods of highviscosity materials have become one of the focal points in the field of circuit printing. Techniques such as laser-induced forward transfer, 16 electrohydrodynamic inkjet, 17 and aerosol jet printing 18 have the capability to handle materials with a viscosity range of up to 1000 MPa or even higher. However, their individual droplet jetting volume is relatively small, resulting in the formation of single layers with a thickness of only several micrometers.…”