Structured illumination microscopy for dual-modality 3D sub-diffraction resolution fluorescence and refractive-index reconstruction

TL;DR

This paper presents a structured illumination microscopy technique that combines fluorescence and refractive-index imaging to achieve 3D sub-diffraction resolution, enabling detailed biological sample visualization at the molecular and biophysical levels.

Contribution

It introduces a dual-modality 3D super-resolution microscopy framework integrating fluorescence and RI imaging, advancing biological imaging capabilities.

Findings

Successfully reconstructed 3D RI and fluorescence images of microspheres.

Demonstrated 3D imaging of biological cells with sub-diffraction resolution.

Validated the method's ability to visualize molecular and biophysical structures.

Abstract

Though structured illumination (SI) microscopy is a popular imaging technique conventionally associated with fluorescent super-resolution, recent works have suggested its applicability towards sub-diffraction coherent imaging with quantitative endogenous biological contrast. Here, we demonstrate that SI can efficiently integrate the principles of fluorescent super-resolution and coherent synthetic aperture to achieve 3D dual-modality sub-diffraction resolution, fluorescence and refractive-index (RI) visualizations of biological samples. Such a demonstration can enable future biological studies to synergistically explore molecular and biophysical/biochemical mechanisms at sub-diffraction resolutions. We experimentally demonstrate this framework by introducing a SI microscope capable of 3D sub-diffraction fluorescence and RI imaging, and verify its biological visualization capabilities by experimentally reconstructing 3D RI/fluorescence visualizations of fluorescent calibration microspheres as well as alveolar basal epithelial adenocarcinoma (A549) and human colorectal adenocarcinmoa (HT-29) cells, fluorescently stained for F-actin.