Holographic intravital microscopy for 2-D and 3-D imaging intact circulating blood cells in microcapillaries of live mice

TL;DR

This paper introduces a holographic microscopy technique for label-free, quantitative 2D and 3D imaging of circulating blood cells in live mice, revealing detailed cellular properties and blood flow dynamics.

Contribution

The study presents a novel in vivo holographic imaging method that provides detailed morphological and biochemical information of blood cells without labels.

Findings

Quantitative 3D imaging of blood cells in live mice.

Measurement of haemoglobin concentration and content at the single-cell level.

Observation of blood flow alterations in sepsis-model mice.

Abstract

Intravital microscopy is an essential tool that reveals behaviours of live cells under conditions close to natural physiological states. So far, although various approaches for imaging cells in vivo have been proposed, most require the use of labelling and also provide only qualitative imaging information. Holographic imaging approach based on measuring the refractive index distributions of cells, however, circumvent these problems and offer quantitative and label-free imaging capability. Here, we demonstrate in vivo two- and three-dimensional holographic imaging of circulating blood cells in intact microcapillaries of live mice. The measured refractive index distributions of blood cells provide morphological and biochemical properties including three-dimensional cell shape, haemoglobin concentration, and haemoglobin contents at the individual cell level. With the present method, alterations in blood flow dynamics in live healthy and sepsis-model mouse were also investigated.