In this study, we have developed an implantable optogenetic device that can measure and stimulate neurons by an optical method based on CMOS IC technology. The device consist of a blue LED array for optically patterned stimulation, a CMOS image sensor for acquiring brain surface image, and eight green LEDs surrounding the CMOS image sensor for illumination. The blue LED array is placed on the CMOS image sensor. We implanted the device in the brain of a genetically modified mouse and successfully demonstrated the stimulation of neurons optically and simultaneously acquire intrinsic optical images of the brain surface using the image sensor. The integrated device can be used for simultaneously measuring and controlling neuronal activities in a living animal, which is important for the artificial control of brain functions.Jpn. J. Appl. Phys. 56, 057001 (2017) M. Haruta et al. 057001-3

A CMOS-based neural interface device equipped with an integrated micro light source array for optogenetics was fabricated and demonstrated. A GaInN LED array formed on sapphire substrate was successfully assembled with a multifunctional CMOS image sensor that is capable of on-chip current injection. We demonstrated a functionality of light stimulation onto ChR2-expressed cells in an in vitro experiment. A ChR2-expressed cell were successfully stimulated with the light emitted from the fabricated device.

Multi-electrode (MEA) assays using human induced pluripotent stem cell (hiPSC)-derived neurons are expected to predict the toxicity and the pharmacological effects. If we can measure the release of neurotransmitter using this MEA, it is possible to evaluate the drug related to release of neurotransmitters, and it is expected to improve the accuracy of medicinal effects. In this study, we aimed to develop the carbon nanotube (CNT) MEA chip, which enables in both electrochemical measurement of DA release and conventional field potential measurement. The CNT-MEA chip was fabricated by electro-plating method. Detection sensitivity to dopamine (DA) in the fabricated CNT-MEA chip was examined by electrochemical measurement method. The change of DA release to methamphetamine (MTH) were measured using cultured human iPSC-derived dopamine neurons on CNT-MEA. As a result of the electrochemical measurement, an oxidation peak current was observed at 0.25 V, and the detection limit and linearity of DA was less than 5 nM. We have succeeded in real time detection of DA release using human iPS cell derived DA neurons, and detected the changes in the amount of DA release depending on MTH dose. Furthermore, in the human iPSC-derived DA neuron, a change of spike pattern at MTH administration was detected by conventional field potential measurement. CNT-MEA is expected as a new MEA measurement method that improves the accuracy of toxicity prediction and the pharmacological effects. Poster Sessions