Inkjet-Printed Silver Electrode Array for in-vivo Electrocorticography.

Electrocorticography (ECoG) is an important neuroscientific tool for acquiring information about brain states and mesoscopic neural activity. Additionally, the use of ECoG and the higher resolution technique micro-ECoG (µECoG) show promise in Brain-Machine Interface (BMI) applications for motor and speech prosthetics. Commercially available µECoG arrays made through photolithographic and vapor-deposition processes allow neuroscientists to incorporate µECoG into their studies, however, these electrode arrays can be expensive and do not lend themselves to easy reconfigurability for experiment-specific electrode layouts. Here we show a process for patterning µECoG electrode arrays using inkjet printing on a 50 µm thick PET substrate. With inkjet printing, we achieve electrode active areas with 300 µm diameters and interconnects with a 500 µm pitch. These electrode arrays demonstrate an average impedance of 2.5 kΩ at 100 Hz and were used to record local field potentials from the mouse somatosensory cortex with signal-to-noise ratios between 30-45 dB. Our results demonstrate the feasibility of using inkjet-patterned µECoG electrode arrays in future neuroscientific studies. Furthermore, we expect printed µECoG arrays to be compatible with roll-to-roll processing for high-throughput and low-cost manufacturing, decreasing the cost-barrier for neuroscientists seeking to incorporate customizable µECoG electrode arrays into their experimental design.