Integration of CMOS and MEMS Technologies in the Development of a Neural Imaging and Interface Device: Showcase of an Emerging Bioimaging Technique

Previously, we reported a new neural imaging approach based on a CMOS imaging device. Using the device, we demonstrated real-time in vivo protease imaging inside the mouse hippocampus. In this work, we explore MEMS microfabrication technologies to develop a next generation device. By embedding electrodes onto the sensor chip and improving the packaging process, we have realized a single device capable of imaging and neural interface. Pt electrodes are embedded onto strategic sites on the image sensor for electrical stimulus and recording. On-chip fluorescence imaging is realized by integrating LED chips and coating the device with a corresponding excitation light filter. Tests were carried out to characterize fluorescence imaging and electrical current injection capability of the device. These tests show that the device can be used for simultaneous imaging and stimulation inside the brain. We have also tested the device in vivo and verified physiologically that the brain continued to function normally with the device implanted inside.