Phase correlation imaging of unlabeled cell dynamics

Abstract

We present phase correlation imaging (PCI) as a novel approach to study cell dynamics in a spatially-resolved manner. PCI relies on quantitative phase imaging time-lapse data and, as such, functions in label-free mode, without the limitations associated with exogenous markers. The correlation time map outputted in PCI informs on the dynamics of the intracellular mass transport. Specifically, we show that PCI can extract quantitatively the diffusion coefficient map associated with live cells, as well as standard Brownian particles. Due to its high sensitivity to mass transport, PCI can be applied to studying the integrity of actin polymerization dynamics. Our results indicate that the cyto-D treatment blocking the actin polymerization has a dominant effect at the large spatial scales, in the region surrounding the cell. We found that PCI can distinguish between senescent and quiescent cells, which is extremely difficult without using specific markers currently. We anticipate that PCI will be used alongside established, fluorescence-based techniques to enable valuable new studies of cell function.

3D Time-lapse Imaging and Quantification of Mitochondrial Dynamics

“… 30 . In addition, the associated diffusion constants we calculate from these data coincide with published quantified cellular dynamics using phase correlation imaging 24 .…”

“…Merging photothermal detection and correlation spectroscopy was previously introduced 21 22 but not with 3D imaging or extended time scales (up to 1 hour) 23 . In a similar manner, phase correlation imaging has also been demonstrated as a robust technique for studying cell dynamics 24 even without the use of specific labels. As we have previously stated, using the poli-OCM we achieved fast 3D mitochondria specific live cell imaging up to 3000 seconds without any loss of contrast (see Fig.…”

The relative densities of cell cytoplasm, nucleoplasm, and nucleoli are robustly conserved during cell cycle and drug perturbations

“…The effects of the nuclear and cytoplasmic mass densities on their mechanical properties, and vice versa, is still unexplored, primarily due to the lack of practical techniques to measure local mechanical properties inside cells. There are emerging non-invasive optical microscopic techniques to probe the mechanical properties of biological samples including Brillouin microscopy (52,73,74), fluorescence lifetime imaging (FLIM) (75,76), and time-lapse quantitative phase microscopy (77). In the future, combining ODT with such other microscopic modalities can reveal the interaction between the mass density and mechanical properties of nucleus and cytoplasm.…”

Development and Application of Optical Coherence Tomography (OCT)

“…Also PS-OCT has been successfully applied for ophthalmic imaging using experimental prototypes [131]. The eye features a variety of tissues exhibiting birefringence or depolarization, which enable PS-OCT to provide additional contrast for discerning, segmenting, and quantifying ocular structures.…”

“…D-FF-OCT is promising, when compared with digital holography techniques [33], dynamic light scattering techniques [110], or quantitative phase imaging [124,130,131], as it provides optical sectioning, and can access a motility-based contrast in 3D in scattering tissues with a subcellular resolution. Additionally, compared with dynamic OCT techniques [116,132], we take advantage of the higher spatial resolution to capture subcellular variations, which further enable the cells to be revealed.…”