Correlative Super-Resolution Imaging of Cellular Nanopores Facilitated by Transparent Polymer Waveguide Chips

Abstract

Super-resolution optical microscopy (SRM) permits the visualization of subcellular structures of biological samples beyond the diffraction limit of light. To evaluate and utilize the specific strengths of each SRM technique a combined approach in the form of correlative super-resolution imaging is essential. Here, the correlative SRM imaging of the ultrastructure of rat liver sinusoidal endothelial cells (LSECs) across a large field of view (FOV) with 3D structured illumination microscopy (3D-SIM) and single-molecule localization microscopy (SMLM), facilitated by a transparent polymer photonic waveguide chip, is presented. This waveguide is not only used for chip-based total internal reflection fluorescence (TIRF) excitation across a large FOV, but also enables the excitation and collection of single-molecule fluorescence via the inverted microscope configuration. Furthermore, the structural design of the waveguides allows to identify and correlate sample positions across multiple microscopes. This correlative SIM and multi-modality SMLM imaging provides a high throughput (FOV of ≈180 μm × 120 μm) method to analyze the structural morphology of LSECs with high spatial resolution (≈50 nm). Furthermore, waveguide chip-based TIRF excitation also yields a significant reduction of background signals.