At the primary care setting, defined by the World Health Organization (WHO) as an area with often no or minimal laboratories available, medical devices must be simple and easy to operate by users with a variety of skill levels. Because of these requirements, fluorescence microscopy has become a standard tool used in both high and low resource laboratories owing to its ability to identify fluorescently stained cells and sub-microscopic cellular components. An alternative design that could simplify the fluorescent microscope involves the use of ultraviolet (UV) illumination. While there is little documentation on fluorescence in the short range UV wavelengths, many fluorescent dyes that are excitable in the visible region are also excitable by UV. Based on this idea, we developed a simple fluorescence microscope built out of commercially available components which uses UV illumination and can image any fluorescent sample (given that the fluorophore can be excited by UV). Because UV is not typically visible on camera detectors and is absorbed by glass components, the separation of excitation light from emitted fluorescence may be easily incorporated into in the design of the microscope, eliminating the need for excitation, emission, and dichroic filters. The simplicity of the designed fluorescent microscope may allow for a more compact and easy to use microscope for the primary care setting as well as decrease the overall cost of manufacturing the device. For biological validation, we imaged whole blood stained with acridine orange (AO) and performed a two-part white blood cell (WBC) differential count.
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