This article, from the journal "Nature," describes the development of a low-cost smartphone fluorescence microscope. The microscope design consists of a plexiglass platform to hold a smartphone or tablet atop the specimen, and a second plexiglass platform positioned below the smartphone lens to serve as a stage to hold the specimen.
An additional clip-on macro lens is clamped over the phone or tablet camera to increase magnification and resolution beyond the smartphone or tablet alone. To equip the microscope with fluorescence imaging capability, fluorescence light sources and filters are added.
For green fluorescence viewing, a blue LED headlamp or flashlight is used, and theater stage lighting filters are placed immediately underneath the clip-on lens and smartphone to block the blue light from reaching the camera lens. For red fluorescence viewing, a green LED flashlight is used, and Rosco stage lighting filter #19 is used as an emission filter positioned underneath the lens to block green light while permitting red fluorescence to pass through to the camera lens.
The required parts are listed and cost around $30-$50 per unit. The converted device is capable of detecting subtle green fluorescence in Tg(phox2b:EGFP) embryos and changes to heart rate and rhythmicity in embryonic zebrafish using green fluorescence imaging. The study concluded that newer smartphone or tablet models were not necessary for glowscope fluorescence viewing. The same setup was also used for non-fluorescent imaging using a LED work lamp positioned underneath the specimen.