Design and construction of a modular low-cost epifluorescence upright microscope for neuron visualized recording and fluorescence detection

Abstract

One of the limitations when establishing an electrophysiology setup, particularly in low resource settings, is the high cost of microscopes. The average cost for a microscope equipped with the optics for infrared (IR) contrast or microfluorometry is $40,000. We hypothesized that optical elements and features included in commercial microscopes are not necessary to IR video-visualize neurons or for microfluorometry. We present instructions for building a low-cost epifluorescence upright microscope suitable for visualized patch-clamp recording and fluorescence detection using mostly catalog-available parts. This microscope supports applications such as visualized whole-cell recording using IR oblique illumination (IR-OI), or more complex applications such as microfluorometry using a photodiode. In both IR-OI and fluorescence, actual resolution measured with 2-μm latex beads is close to theoretical resolution. The lack of movable parts to switch configurations ensures stability when doing intracellular recording. The low cost is a significant advantage of this microscope compared to existent custom-built microscopes. The cost of the simplest configuration with IR-OI is ∼$2000, whereas the cost of the configuration with epifluorescence is ∼$5000. Since this design does not use pieces discarded from commercial microscopes, it is completely reproducible. We suggest that this microscope is a viable alternative for doing in vitro electrophysiology and microfluorometry in low-resource settings. Characteristics such as an open box design, easy assembly, and low-cost make this microscope a useful instrument for science education and teaching for topics such as optics, biology, neuroscience, and for scientific "hands-on" workshops.