Label-free correlative morpho-chemical tomography of 3D kidney mesangial cells

TL;DR

This paper presents a label-free, correlative imaging technique combining SLAM and GLIM to obtain 3D morphological and chemical information of kidney mesangial cells, aiding in understanding kidney function and pathology.

Contribution

It introduces a novel correlative approach that integrates autofluorescence multi-harmonic and gradient light interference microscopy for comprehensive 3D cellular imaging without labels.

Findings

Successful 3D imaging of kidney mesangial cells with chemical and morphological data

Quantitative phase imaging of samples up to 250 microns thick

Potential to study cell metabolism and matrix deposition in physiological conditions

Abstract

Label-free characterization of biological specimens seeks to supplement existing imaging techniques and avoid the need for contrast agents that can disturb the native state of living samples. Conventional label-free optical imaging techniques are compatible with living samples but face challenges such as poor sectioning capability, fragmentary morphology, and lack chemical specific information. Here, we combined simultaneous label-free autofluorescence multi-harmonic (SLAM) microscopy and gradient light interference microscopy (GLIM) to extract both chemical specific and morphological tomography of 3D cultured kidney mesangial cells. Imaging 3D in vitro kidney models is essential to understand kidney function and pathology. Our correlative approach enables imaging and quantification of these cells to extract both morphology and chemical-specific signals that is crucial for understanding kidney function. In our approach, SLAM offers a nonlinear imaging platform with a single-excitation source to simultaneously acquire autofluorescence (FAD and NAD(P)H), second, and third harmonic signal from the 3D cultured cells. Complementarily, GLIM acquires high-contrast quantitative phase information to quantify structural changes in samples with thickness of up to 250 micron. Our correlative imaging results demonstrate a versatile and hassle-free platform for morpho-chemical cellular tomography to investigate functions such as metabolism and matrix deposition of kidney mesangial cells in 3D under controlled physiological conditions.