Dynamic optical coherence tomography for cell analysis [Invited]

Abstract

Label-free live optical imaging of dynamic cellular and subcellular features has been made possible in recent years thanks to the advances made in optical imaging techniques, including dynamic optical coherence tomography (D-OCT) methods. These techniques analyze the temporal fluctuations of an optical signal associated with the active movements of intracellular organelles to obtain an ensemble metric recapitulating the motility and metabolic state of cells. They hence enable visualization of cells within compact, static environments and evaluate their physiology. These emerging microscopies show promise, in particular for the three-dimensional evaluation of live tissue samples such as freshly excised biopsies and 3D cell cultures. In this review, we compare the various techniques used for dynamic OCT. We give an overview of the range of applications currently being explored and discuss the future outlook and opportunities for the field.

zIncubascope: long-term quantitative imaging of multi-cellular assemblies inside an incubator

“…This may require to "clear" the sample to reduce light absorption and scattering 3,4 with chemical treatment leading to sample fixation. Alternatively, optical techniques such as Optical Coherence Tomography (OCT) 5,6 intrinsically improve the depth of light penetration and are exquisitely suited for live imaging since they are label-free methods and thus induce very low photo-toxicity. The second issue, which becomes crucial for screening applications, eg.…”

Line-field dynamic optical coherence tomography platform for volumetric assessment of biological tissues

“…While originally OCT was developed for morphological imaging, over the past three decades different system designs, data acquisition protocols and data processing algorithms have been developed to expand the application of OCT to mapping blood vasculature, measuring blood flow, blood oxygenation and blood glucose concentration, assessing physiological processes and mapping birefringence in biological tissues [ 2 ]. Dynamic OCT is one such example where OCT data is collected repeatedly from the imaged object over an extended period of time and the temporal changes in the OCT interferogram (intensity and phase) are analyzed to extract information about the motility of biological cells and their organelles [ 3 ]. The motility data can be used in several ways: as an indirect measure of the cellular metabolic and physiological processes, including apoptosis [ 4 – 9 ]; as a method to enhance image contrast in morphological OCT images, in order to improve the visualization of cells and their nuclei [ 10 – 13 ]; and as a potential method for label-free identification of cell types [ 10 , 14 , 15 ].…”