Implementation and testing of a biohybrid transition microelectrode array for neural recording and modulation

Recent advances in microtissue engineered neural networks have opened avenues for the fabrication of biohybrid intracortical brain implants. To date, however, the experimental validation of these biohybrid implants has been restricted to singularly positioned electrodes, with the functionality confined to optical neuromodulation and neural recording. We present for the first time a biohybrid transition microelectrode array (TMEA) comprising a 4×4 matrix of biohybrid electrodes. These electrodes are expected to project axons into the brain, thereby establishing synaptic connections for electrical readout and excitation. Our device thus offers a promising pathway to leverage organic, endogenous materials in intracortical implants to enhance their biocompatibility as well as their functionality. In particular with respect to functionality, we assume that the spatiotemporal resolution of recorded neural signals may be significantly increased using this technology owing to the size ratios of these biohybrid microelectrodes compared to abiotic ones. Future investigations will therefore focus on the exploitation of the electrode density to further advance brain-computer interface technology. ### Competing Interest Statement The authors declare the following competing financial interests that are overseen through the University of Utah conflict of interest management: Fan, Y., Reiche, C. F. and Solzbacher, F. Implantable Transition Microylectrode Array, 00846-U6846.PCT, 2022. F. Solzbacher declares a financial interest in Sentiomed, Inc. and Blackrock Neurotech.