arXiv subjects

Tual Monfort

Publications and source records attributed to Tual Monfort.

5 recordsLinked to original sources

arXiv2026

Dynamic dark-field FFOCT and dynamic reflection differential phase contrast for label-free functional imaging at reflective biomaterial interfaces

Strong reflections from metallic and engineered substrates severely limit label-free functional imaging of living cells at biomaterial interfaces, neural electrodes, and implantable devices. Here we introduce two complementary approaches for recovering intracellular dynamic contrast at highly reflective interfaces. Dynamic dark-field full-field optical coherence tomography (D-dFFOCT) suppresses the dominant substrate reflection and restores intracellular visibility through selective detection of scattered light. In parallel, asymmetric illumination generates a distinct directional dynamic contrast that is most consistently interpreted as dynamic reflection differential phase contrast (D-RDPC). Both approaches reveal intracellular activity that remains poorly visible with conventional dynamic full-field optical coherence tomography. D-RDPC exhibits characteristic signatures of phase-gradient imaging, including contrast reversal upon illumination inversion, enhancement with increasing illumination asymmetry, and recovery of spatial localization through directional Hilbert-transform reconstruction. Together, these results establish new strategies for functional imaging at reflective interfaces and suggest that differential phase contrast signals can support temporal fluctuation analysis.

physics.optics↗

arXiv2025

Rolling phase modulation regime for dynamic full field OCT

Dynamic full-field optical coherence tomography (DFFOCT) has recently emerged as an invaluable label-free microscopy technique, owing to its sensitivity to cell activity, as well as speed and sectioning ability. However, the quality of DFFOCT images are often degraded due to phase noise and fringe artifacts. In this work, we present a new implementation named Rolling-Phase (RP) DFFOCT, in which the reference arm is slowly scanned over magnitudes exceeding 2$\pi$. We demonstrate mathematically and experimentally that it shows superior image quality while enabling to extract both static and dynamic contrast simultaneously. We showcase RP DFFOCT on monkey retinal explant, and demonstrate its ability to better resolve subcellular structures, including intranuclear activity.

q-bio.QM↗

arXiv2024

Impact of maternal high fat on neurovascular unit of adult offspring

Maternal obesity is associated with increased risk of diabetes, cardiovascular disease and hypertension in adult offspring. Midlife hypercholesterolemia and hypertension are risk factors for Alzheimer's disease, suggesting that the ageing brain may be impacted by early life environment. We found that exposure to a high fat diet during gestation and lactation induced changes in multiple components of the neurovascular unit, including a downregulation in apolipoprotein E and fibronectin, an upregulation in markers of astrocytes and perivascular macrophages and altered blood vessel morphology in the brains of adult mice. Feeding of high fat diet after weaning increased lipid droplets in the brain and influenced the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine species, but did not affect the neurovascular unit. Sustained high fat diet over the entire lifespan resulted in additional decreases in levels of pericytes and collagen IV, changes in phospholipid composition and impaired perivascular clearance of Beta-amyloid (A-Beta) from the brain. In humans, vascular A-Beta load was significantly increased in the brains of aged individuals with a history of hypercholesterolemia. These results support a critical role for early dietary influence on the brain vasculature across the lifespan, with consequences for the development of age-related cerebrovascular and neurodegenerative diseases.

q-bio.TO↗

arXiv2023

Interface Self-Referenced Dynamic Full-Field Optical Coherence Tomography

Dynamic full-field optical coherence tomography (D-FFOCT) has recently emerged as an invaluable live label-free and non-invasive imaging modality able to image subcellular biological structures and their metabolic activity within complex 3D samples. However, D-FFOCT suffers from fringe artefacts when imaging nearby reflective surfaces and is highly sensitive to vibrations. Here, we present interface Self-Referenced (iSR) D-FFOCT, an alternative configuration to D-FFOCT that takes advantage of the presence of the sample coverslip in between the sample and the objective by using it as a defocused reference arm, thus avoiding the aforementioned artefacts. We demonstrate the ability of iSR D-FFOCT to image 2D fibroblast cell cultures, which are among the flattest mammalian cells.

physics.optics↗

arXiv2023

Dynamic Full-Field Optical Coherence Tomography module adapted to commercial microscopes for longitudinal in vitro cell culture study

Dynamic full-field optical coherence tomography (D-FFOCT) has recently emerged as a label-free imaging tool, capable of resolving cell types and organelles within 3D live samples, whilst monitoring their activity at tens of milliseconds resolution. Here, a D-FFOCT module design is presented which can be coupled to a commercial microscope with a stage top incubator, allowing non-invasive label-free longitudinal imaging over periods of minutes to weeks on the same sample. Long term volumetric imaging on human induced pluripotent stem cell-derived retinal organoids is demonstrated, highlighting tissue and cell organisation as well as cell shape, motility and division. Imaging on retinal explants highlights single 3D cone and rod structures. An optimal workflow for data acquisition, postprocessing and saving is demonstrated, resulting in a time gain factor of 10 compared to prior state of the art. Finally, a method to increase D-FFOCT signal-to-noise ratio is demonstrated, allowing rapid organoid screening.

q-bio.QM↗