Fully-Automated Multicolour Structured Illumination Module for Super-resolution Microscopy

Abstract In the rapidly advancing field of biological imaging, there is a great need for high-resolution imaging techniques that are both cost-effective and accessible, for example to better observe and understand dynamics in intracellular processes. Structured illumination microscopy (SIM) is the method of choice to achieve high axial and lateral resolution in living samples due to its optical sectioning and minimal phototoxicity. However, the high cost and complexity of conventional SIM systems limit their wide application. In our work, we present an open-source, fully-automated, two-color structured illumination module that is compatible with commercially available microscope stands. The compact design, consisting of low-cost single-mode fiber-coupled lasers and a digital micromirror device (DMD), is integrated into the open-source acquisition and control software (ImSwitch) in order to realize real-time super-resolution imaging. This developed system achieves up to a 1.55-fold improvement in lateral resolution compared to conventional wide-field microscopy. To rationally design this module, we developed a model to ensure optimal DMD diffraction per-formance using tilt and roll pixels, thus covering a wide range of low-cost video projectors for use in coherent SIM setups. Our goal is to democratize SIM-based super-resolution microscopy by providing both comprehensive open-source documentation and a modular software framework that works with various hardware components (e.g. cameras, stages) and reconstruction algorithms. In this way, we try to upgrade as many devices as possible to the super-resolution realm.