An implantable green fluorescence imaging device using absorption filters with high excitation light rejection ratio

We have developed an implantable complementary-metal-oxide-semiconductor (CMOS) imaging device for green fluorescence imaging to observe various neural activities of the mouse brain in a freely moving state. The device comprises a CMOS image sensor, blue LEDs as excitation light sources, and absorption filters to enable real-time green fluorescence imaging. To observe weak green fluorescence reactions such as that of green fluorescent protein (GFP), we achieved efficient excitation light rejection using a combination of dedicated absorption filters and achieved the detection of GFP positive cells from mouse brain slices. It is expected that high-sensitivity green fluorescence imaging of neural activities in a freely moving mouse will be possible using this technology.