Maskless Fabrication of PLA‐Based Neural Arrays for CNS Recording and Stimulation

Micro‐electrode arrays based on poly‐lactic acid substrates featuring gold electrodes coated with poly(3,4‐ethylenedioxythiophene)/poly(styrenesulfonate) are fabricated via maskless wet‐techniques and subtractive laser patterning. Devices exhibit stable electrical performance at the bench‐side over weeks and enable high‐quality neural interfacing in acute in vivo experiments. Two device layouts are presented: one for micro‐epicorticography and one for spinal cord stimulation. Cortical arrays are benchmarked against somatosensory evoked potentials in bilateral micro‐electrocorticography, showing robust contralateral activation and negative ipsilateral control. Spinal arrays activate sensory and motor pathways according to spatial features of the injected electric field, at fixed stimulation frequency and intensity, thus demonstrating localized stimulation. Long‐term (4‐months) implantation of spinal arrays results in almost complete substrate degradation and good device biocompatibility. These results demonstrate a versatile and sustainable fabrication workflow for prototyping of biodegradable substrate‐based neural interfaces, which opens new opportunities for transient neuroelectronics tailored to the application and the patient.