Structured illumination for 3D subdiffraction reconstruction of refractive-index and fluorescence (Conference Presentation)

Abstract

Refractive-index (RI) is an inherent optical property of materials that can provide important biochemical and biophysical information about a biological sample. Optical-diffraction-tomography (ODT) is a current standard to obtain quantitative three-dimensional RI distributions, by measuring optical fields diffracted from the sample by rotated illumination beams. This method for ODT also synthetically enlarges the microscope’s lateral spatial-frequency support, and thus images the RI distribution with lateral resolution beyond the microscope's coherent diffraction limit. Fluorescence microscopy offers a complementary set of biological insights by offering imaging capabilities with molecular specificity. Analogous to ODT, super-resolution fluorescence techniques can offer these insights at spatial resolutions beyond the microscope's incoherent diffraction limit. Unfortunately, such super-resolution techniques are generally incompatible with ODT and a generalized sub-diffraction technique has been difficult to find, which hinders a cohesive, high-resolution, multimodal analysis of biological samples. We experimentally introduce, for the first time to our knowledge, a novel, high resolution, optical system that uses structured illumination (SI) to enable 3D sub-diffraction resolution imaging for both fluorescence and RI. We demonstrate sub-diffraction resolution, multimodal SI imaging of HT29 and MCF7 cells fluorescently stained for F-actin, such that the 3D RI and fluorescent distributions may offer unique, but complementary, insights into the biological samples.