A Novel Lensless Miniature Contact Imaging System for Monitoring Calcium Changes in Live Neurons

Here, we report on the design, fabrication, and verification of a novel CMOS-imager-based contact imaging system. We acquired fluorescent images from live neurons by monitoring calcium changes with Fura-2 dye. Our current device consists of a removable absorption filter interfaced with a CMOS imaging sensor and an external DG-4 lamp for excitation. Fura-2 loaded Lymnaea stagnalis neurons were stimulated with dual excitation wavelengths of 340 and 380 nm; our image sensor detected 510-nm emission. We show that our system is capable of detecting intracellular calcium changes in Fura-2 loaded neurons. Further, this sensor also enabled viewing of multiple neurons over a large surface area simultaneously, an option that is not readily available in conventional light microscopy.