Facile assembly of an affordable miniature multicolor fluorescence microscope made of 3D-printed parts enables detection of single cells

Fluorescence microscopy is one of the workhorses of biomedical research and laboratory diagnosis; however, their cost, size, maintenance, and fragility has prevented their adoption in developing countries or low-resource settings. Although significant advances have decreased their size, cost and accessibility, their designs and assembly remain rather complex. Here, inspired on the simple mechanism from a nut and a bolt we report the construction of a portable fluorescence microscope that operates in bright field mode and in three fluorescence channels: UV, green, and red. It is assembled in under 10 min from only six 3D printed parts and basic electronic components that can be readily purchased in most locations or online for US $85. Adapting a microcomputer and a touch LCD screen, the microscope can capture time-lapse images and videos. We characterized its resolution and illumination conditions and benchmarked its performance against a high-end fluorescence microscope by tracking a biological process in single cells. We also demonstrate its application to image cells inside a microfluidic device in bright-field and fluorescence mode. Our microscope fits in a CO2 chamber and can be operated in time-lapse mode. Our portable microscope is ideal in applications where space is at a premium, such as lab-on-a-chips or space missions, and can find applications in clinical research, diagnostics, telemedicine and in educational settings.