| 研究実績の概要 |
Current technologies for brain studies are electrophysiological recording and optical imaging, both of which retain unique yet complementary advantages, advancing our fundamental understanding of brain functions. However, electrophysiological recordings performed by microelectrode have low spatial resolution limited by the number and size of electrodes, while optical imaging relies on the bulky optics and fluorescent reporters of neuronal dynamics. Here a new class of implantable, biocompatible and label-free microscope device was introduced based on a field-effect sensor, i.e., the light-addressable potentiometric sensor (LAPS) with insulator-semiconductor structure, and flexible polymer fibers with electrodes and optical waveguide bundles, for deep brain imaging. The LAPS can convert the brain electric activities at the brain-insulator interface into carrier redistribution within the semiconductor via the field effect. Moreover, thanks to the photoelectronic effect of the semiconductor, localized surface potential change can be read out in the form of an ac photocurrent induced by a modulated light beam. In this way, image of brain activities can be performed by simultaneously mapping photocurrents at each measurement spot illuminated by light modulated at different frequencies. In this study, an implantable label-free microscope device based on field-effect sensor and multifunctional polymer fibers was developed. It has been demonstrated that this device can be implanted into the deep brain regions of mice and record low-frequency brain events with high fidelity.
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