µ12: Cost-effective DIY microscope

The widespread adoption of rapid prototyping technologies has enabled the development of numerous, easily implementable solutions across nearly every area of science and engineering. Microscopy, particularly in life and materials sciences, has benefited from this trend. The literature features various microscope designs that can be assembled at relatively low cost or even built at home. While some proposals rely on conventional microscope objectives and eyepieces, increasing their cost, others sacrifice optical performance to uphold the do-it-yourself (DIY) and low-cost promises. In this work, we present a DIY bright-field microscope that employs M12 lenses assembled into a modular 3D-printed platform to build a competitive optical device, hereafter referred to as µ12. The M12 lenses, arranged in a telecentric configuration, enable a cost-effective microscope with near diffraction-limited performance and a flat field of view. The µ12 supports both handheld and desktop operation, combining a compact optical head, interchangeable reversed M12 objectives, integrated high-intensity LED illumination, and a manual X-Y-Z stage. With the tested M12 objectives, the system provides magnifications from 4.2X to 8.9X, while resolution tests indicate an effective resolving capability of about 1.2 µm for the best-performing objective. The imaging capabilities of the µ12 are compared to those of a high-end research-grade commercial microscope, demonstrating a highly competitive performance despite its significantly reduced cost. The proposed microscope is benchmarked with both resolution test targets and biological specimens. Furthermore, the µ12 is integrated into the ImageJ ecosystem to leverage its built-in functionalities, like image acquisition, MTF evaluation and analysis tools.