Lateral shearing optical diffraction tomography of brain organoid with reduced spatial coherence

TL;DR

This paper introduces lateral shearing optical diffraction tomography (LS-ODT), a novel interferometric method that improves 3D imaging of heterogeneous, thick biological samples like brain organoids by suppressing multiple scattering effects.

Contribution

The work presents a new LS-ODT technique combining lateral shearing interferometry and dynamic speckle illumination for enhanced imaging of complex biological tissues.

Findings

Successfully imaged brain organoids and tissue sections with high accuracy.

Demonstrated robustness of LS-ODT across various biological samples.

Enhanced spatial phase and RI sensitivity compared to traditional laser-based ODT.

Abstract

Optical diffraction tomography (ODT) is a powerful technique for quantitative, label-free reconstruction of the three-dimensional refractive index (RI) distribution of biological samples. While ODT is well established for imaging thin, weakly scattering samples, it encounters significant challenges when applied to heterogeneous, strongly scattering thick samples such as tissues and organoids. In this work, a novel common-path interferometric approach to ODT is presented, specifically designed for the RI reconstruction of heterogeneous and highly scattering samples at high temporal stability. The proposed technique, termed lateral shearing (LS)-ODT, incorporates partial lateral shearing off-axis interferometry to suppress the effects of multiple scattering, similar to the mechanism in differential interference contrast (DIC) microscopy, which is widely used for imaging thick specimens. Additionally, the LS-ODT system uses dynamic speckle illumination to enhance both spatial phase and RI sensitivity compared to laser-based ODT systems. The effectiveness of this method is demonstrated through experiments on a cell phantom. Its robustness and accuracy are further validated across a wide range of samples, including mouse kidney tissue sections and brain organoids derived from human induced pluripotent stem cells (iPSCs), in both thin and thick sections. Furthermore, correlative fluorescence and RI tomography of the organoids highlights the potential of LS-ODT to enhance and support a broad spectrum of biomedical studies, particularly in the field of histology.