Customizable Fabrication of 2D and Conformal Multielectrode Arrays for 3D Printed Organotypic Bioelectronic...

Organotypic 3D tissue models require precise electrophysiological interfaces to study function and disease. Multi-electrode arrays (MEAs) are essential for recording and stimulation, yet conventional fabrication methods are costly and time-intensive. This study demonstrates aerosol jet printing (AJP) of gold nanoparticles onto flexible polyimide substrates to produce fully gold, biocompatible MEAs for rapid customization of MEAs. Fabrication time is reduced from ≈320 min (photolithography) to ≈175 min, with minimal material waste. Printed electrodes achieve low impedance (0.05 kΩ µm^{- 2} at 1 kHz) with stable performance over 14 days. Coating with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) increases charge injection capacity and maintains stability over 200 000 stimulation pulses. Cytocompatibility is confirmed through direct 3D bioprinting of C2C12 myoblast-laden gelatin methacryloyl (GelMA) onto MEAs, achieving 70-80% viability. Electrical stimulation induces myoblast alignment, and extracellular recordings from primary cortical neurons and HL-1 cardiomyocytes yield signal-to-noise ratios of 20.89 and 16.62 dB, respectively. Integration into 3D-printed hydrogel conduits demonstrates conformal application and enhanced cell organization. These findings establish AJP as a scalable fabrication approach for customizable MEAs, supporting the development of advanced bioelectronic interfaces for organotypic tissue models.