Structured illumination microscopy (SIM) is an advanced optical microscopy technique that can improve the resolution of images beyond the diffraction limit of conventional fluorescence microscopy. The technique is based on the illumination of the sample with a structured light pattern and the subsequent software reconstruction of the high-resolution image from several recorded images. We present the development of a custom-built setup for SIM equipped with a specially developed transmission diffraction grating. Using the analogue microfilming method, we have produced transmission diffraction gratings tailored to the specific requirements of our system. This robust and cost-effective method enables the production of diffraction gratings with customised constants that ensure excellent transmission in both the visible and near-infrared spectrum. To evaluate the performance of our system, we measured the resolution in both epifluorescent and superresolution imaging modalities by applying the knife-edge technique to the MoS2 monolayer flakes. We confirmed an improvement in the resolution of SIM over the epifluorescent imaging modality. Furthermore, we successfully demonstrated the capabilities of our microscope by imaging fluorescently labelled astrocytes in vitro, specifically targeting the vimentin filament protein in these cells. The super-resolved images reveal fine structures of the vimentin cytoskeleton that remain unresolved in the epifluorescent image.