scholarly journals Dehydration of plant cells shoves nuclei rotation allowing for 3D phase-contrast tomography

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhe Wang ◽  
Vittorio Bianco ◽  
Daniele Pirone ◽  
Pasquale Memmolo ◽  
Massimiliano Maria Villone ◽  
...  
Keyword(s):  
Refractive Index ◽  
Phase Contrast ◽  
Ad Hoc ◽  
Turgor Pressure ◽  
Dry Mass ◽  
Label Free ◽  
3D Tomography ◽  
Index Distribution ◽  
Onion Epidermal Cells ◽  
Phase Contrast Tomography

AbstractSingle-cell phase-contrast tomography promises to become decisive for studying 3D intracellular structures in biology. It involves probing cells with light at wide angles, which unfortunately requires complex systems. Here we show an intriguing concept based on an inherent natural process for plants biology, i.e., dehydration, allowing us to easily obtain 3D-tomography of onion-epidermal cells’ nuclei. In fact, the loss of water reduces the turgor pressure and we recognize it induces significant rotation of cells’ nuclei. Thanks to the holographic focusing flexibility and an ad-hoc angles’ tracking algorithm, we combine different phase-contrast views of the nuclei to retrieve their 3D refractive index distribution. Nucleolus identification capability and a strategy for measuring morphology, dry mass, biovolume, and refractive index statistics are reported and discussed. This new concept could revolutionize the investigation in plant biology by enabling dynamic 3D quantitative and label-free analysis at sub-nuclear level using a conventional holographic setup.

scholarly journals Image-based analysis of living mammalian cells using label-free 3D refractive index maps reveals new organelle dynamics and dry mass flux

PLoS Biology ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. e3000553 ◽  
Author(s):  
Patrick A. Sandoz ◽  
Christopher Tremblay ◽  
F. Gisou van der Goot ◽  
Mathieu Frechin
Keyword(s):  
Refractive Index ◽  
Mass Flux ◽  
Mammalian Cells ◽  
Dry Mass ◽  
Label Free ◽  
Index Maps

Culturing Cells on Flexible Substrates of High Refractive Indexes

2012 ◽  
Vol 1418 ◽  
Author(s):  
You-Ren Liu ◽  
Po-Ling Kuo
Keyword(s):  
Refractive Index ◽  
Cell Adhesion ◽  
Phase Contrast ◽  
Human Lung ◽  
Structured Illumination ◽  
Adenocarcinoma Cells ◽  
Human Lung Adenocarcinoma Cells ◽  
Cellular Behaviors ◽  
Phase Contrast Tomography ◽  
Composite Substrates

ABSTRACTMechanical cues in cellular microenvironment are central in directing a class of cellular behaviors such as the dynamic of cell adhesion, migration, and differentiation. Several advanced optical techniques, such as structured-illumination nano-profilometry (SINAP), have been developed for a better resolution of these dynamic processes. These techniques however require culturing cells on materials of refractive index close to that of glass, while most studies regarding the effects of mechanical cues on cellular dynamics were conducted on hydrogel-based substrates. Here we report the development of culturing substrates of tunable rigidity and refractive index suitable for SINAP studies. Polyvinyl chloride (PVC)-based substrates were mixed with a softener called Di(isononyl) Cyclohexane-1,2-Dicarboxylate (DINCH) and cured by heating. The volume ratios of PVC to DINCH were varied from 1:1 to 3:1. The Young’s modulus of the resulting substrates ranged from 18 kPa to 40 kPa. The yielded refractive indices of the composite substrates as measured by phase contrast tomography ranged from 1.47 to 1.53. Human lung adenocarcinoma cells CL1-5 were cultured on the composite substrates and cell viability was examined using the MTT assay. The dynamics of cell adhesion and filopodia activities were examined using SINAP. Preliminary results suggest that PVC based culturing substrates have a great potential in the application of SINAP based studies.

scholarly journals 3D Spatial Distribution of Nanoparticles in Mice Brain Metastases by X-ray Phase-Contrast Tomography

2021 ◽  
Vol 11 ◽  
Author(s):  
Elena Longo ◽  
Lucie Sancey ◽  
Alessia Cedola ◽  
Emmanuel L. Barbier ◽  
Alberto Bravin ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Label Free ◽  
Reliable Technique ◽  
Heterogeneous Distribution ◽  
X Ray ◽  
Non Invasive ◽  
Melanoma Metastases ◽  
Distribution In Organs ◽  
3D Information ◽  
Phase Contrast Tomography

Characterizing nanoparticles (NPs) distribution in multiple and complex metastases is of fundamental relevance for the development of radiological protocols based on NPs administration. In the literature, there have been advances in monitoring NPs in tissues. However, the lack of 3D information is still an issue. X-ray phase-contrast tomography (XPCT) is a 3D label-free, non-invasive and multi-scale approach allowing imaging anatomical details with high spatial and contrast resolutions. Here an XPCT qualitative study on NPs distribution in a mouse brain model of melanoma metastases injected with gadolinium-based NPs for theranostics is presented. For the first time, XPCT images show the NPs uptake at micrometer resolution over the full brain. Our results revealed a heterogeneous distribution of the NPs inside the melanoma metastases, bridging the gap in spatial resolution between magnetic resonance imaging and histology. Our findings demonstrated that XPCT is a reliable technique for NPs detection and can be considered as an emerging method for the study of NPs distribution in organs.

scholarly journals Constrained Non-Linear Phase Retrieval for Single Distance Xray Phase Contrast Tomography

2020 ◽  
Vol 2020 (14) ◽  
pp. 146-1-146-8
Author(s):  
K. Aditya Mohan ◽  
Dilworth Y. Parkinson ◽  
Jefferson A. Cuadra
Keyword(s):  
Inverse Problem ◽  
Refractive Index ◽  
Phase Contrast ◽  
Phase Retrieval ◽  
Transmission Function ◽  
Linear Phase ◽  
Linear Inverse Problem ◽  
X Ray ◽  
Non Linear ◽  
Phase Contrast Tomography

X-ray phase contrast tomography (XPCT) is widely used for 3D imaging of objects with weak contrast in X-ray absorption index but strong contrast in refractive index decrement. To reconstruct an object imaged using XPCT, phase retrieval algorithms are first used to estimate the X-ray phase projections, which is the 2D projection of the refractive index decrement, at each view. Phase retrieval is followed by refractive index decrement reconstruction from the phase projections using an algorithm such as filtered back projection (FBP). In practice, phase retrieval is most commonly solved by approximating it as a linear inverse problem. However, this linear approximation often results in artifacts and blurring when the conditions for the approximation are violated. In this paper, we formulate phase retrieval as a non-linear inverse problem, where we solve for the transmission function, which is the negative exponential of the projections, from XPCT measurements. We use a constraint to enforce proportionality between phase and absorption projections. We do not use constraints such as large Fresnel number, slowly varying phase, or Born/Rytov approximations. Our approach also does not require any regularization parameter tuning since there is no explicit sparsity enforcing regularization function. We validate the performance of our non-linear phase retrieval (NLPR) method using both simulated and real synchrotron datasets. We compare NLPR with a popular linear phase retrieval (LPR) approach and show that NLPR achieves sharper reconstructions with higher quantitative accuracy.

Sign in / Sign up

Export Citation Format

Share Document