A novel dual mode microelectrode array for neuroelectrical and neurochemical recording in vitro

The communication between neurons is inherently electrical and chemical in nature. In situ, simultaneous acquisition for the dual mode signals is important for neuroscience research. In this paper, the concept of dual mode neural microelectrode array (MEA) sensor was proposed, and a low cost thin film MEA chip for in vitro test was fabricated using standard lithography technology. The sensor incorporates arrayed microelectrodes, a counter electrode and a reference electrode on one glass slide, which is suitable for electrophysiological and electrochemical recording in vitro. Electrophysiological recordings were carried out on acute hippocampus slice. Local field potentials and three different spike firing patterns with the amplitude ranging from ± 20 μV to ± 60 μV were acquired by the arrayed microelectrodes. Electrochemical current response of the microelectrodes to calibrated dopamine solution was tested. A good linear relationship between the current and dopamine concentration was observed, with the detection sensitivity of 4671 μA mM(-1)cm(-2) and a correlation coefficient of 0.986. The sensor is novel for its capability of detecting in vitro dual mode neural signals on one single chip.