Intestinal organoid co-culture systems: current approaches, challenges, and future directions.

The intestinal microenvironment represents a complex and dynamic ecosystem, comprising a diverse range of epithelial and non-epithelial cells, a protective mucus layer, and a diverse community of gut microbiota. Understanding the intricate interplay between these components is essential for uncovering the mechanisms underlying intestinal health and disease. The development of intestinal organoids, 3D mini-intestines that closely mimic the architecture, cellular diversity, and functionality of the intestine, offers a powerful platform for investigating different aspects of intestinal physiology and pathology.

Optical Cellular Micromotion: A New Paradigm to Measure Tumor Cells Invasion within Gels Mimicking the 3D Tumor Environments.

Measuring tumor cell invasiveness through 3D tissues, particularly at the single-cell level, can provide important mechanistic understanding and assist in identifying therapeutic targets of tumor invasion. However, current experimental approaches, including standard in vitro invasion assays, have limited physiological relevance and offer insufficient insight into the vast heterogeneity in tumor cell migration through tissues. To address these issues, here the concept of optical cellular micromotion is reported on, where digital holographic microscopy is used to map the optical nano- to submicrometer thickness fluctuations within single-cells.

A systematic investigation of the effect of the fluid shear stress on Caco-2 cells towards the optimization of epithelial organ-on-chip models.

Epithelial cells experience constant mechanical forces, including fluid shear stress (FSS) on their apical surface. These forces alter both structure and function. While precise recapitulation of the complex mechanobiology of organs remains challenging, better understanding of the effect of mechanical stimuli is necessary towards the development of biorelevant in vitro models.

Reconfigurable liquid-core/liquid-cladding optical waveguides with dielectrophoresis-driven virtual microchannels on an electromicrofluidic platform.

An electrically reconfigurable liquid-core/liquid-cladding (L(2)) optical waveguide with core liquid γ-butyrolactone (GBL, ncore = 1.4341, εcore = 39) and silicone oil (ncladding = 1.401, εcladding = 2.

Advanced micromachining of concave microwells for long term on-chip culture of multicellular tumor spheroids.

A novel approach based on advanced micromachining is demonstrated to fabricate concave microwell arrays for the formation of high quality multicellular tumor spheroids. Microfabricated molds were prepared using a state-of-the-art CNC machining center, containing arrays of 3D convex micropillars with size ranging from 150 μm to 600 μm. Microscopic imaging of the micropillars machined on the mold showed smooth, curved microfeatures of a dramatic 3D shape.

Image alignment for tomography reconstruction from synchrotron X-ray microscopic images.

A synchrotron X-ray microscope is a powerful imaging apparatus for taking high-resolution and high-contrast X-ray images of nanoscale objects. A sufficient number of X-ray projection images from different angles is required for constructing 3D volume images of an object. Because a synchrotron light source is immobile, a rotational object holder is required for tomography.

FTIR spectro-imaging of collagen scaffold formation during glioma tumor development.

Evidence has recently emerged that solid and diffuse tumors produce a specific extracellular matrix (ECM) for division and diffusion, also developing a specific interface with microvasculature. This ECM is mainly composed of collagens and their scaffolding appears to drive tumor growth. Although collagens are not easily analyzable by UV-fluorescence means, FTIR imaging has appeared as a valuable tool to characterize collagen contents in tissues, specially the brain, where ECM is normally devoid of collagen proteins.

Fate of intravenously administered gold nanoparticles in hair follicles: follicular delivery, pharmacokinetic interpretation, and excretion.

Gold nanoparticles (GNPs) are intravenously administered to mice. Deposition at the pilosebacious unit and whiskers is visualized with X-ray fluorescence after 30 minutes and 14 days. After 30 minutes the dermal papilla, bulge region, and root sheath all contain NPs.

Immunospecific targeting of CD45 expressing lymphoid cells: towards improved detection agents of the sentinel lymph node.

This study was designed to demonstrate the potential of small nanoparticulate lymphotropic contrast agents designed to bind with high affinity to lymphoid cells overexpressing the CD45 antigen. To this end, small gold nanoparticles used as model were conjugated to anti-CD45 antibodies and injected in mice in the dorsal toe of the fore/hind paw. Chemical analysis demonstrated rapid uptake and transport of the nanoparticles in the lymphatic as well as significant retention of the nanoparticles with high binding affinity to lymphoid cells in the popliteal and axillary lymph nodes in comparison to non-targeted nanoparticles.

X-ray imaging of tumor growth in live mice by detecting gold-nanoparticle-loaded cells.

We show that sufficient concentrations of gold nanoparticles produced by an original synthesis method in EMT-6 and CT-26 cancer cells make it possible to detect the presence, necrosis and proliferation of such cells after inoculation in live mice. We first demonstrated that the nanoparticles do not interfere with the proliferation process. Then, we observed significant differences in the tumor evolution and the angiogenesis process after shallow and deep inoculation.

Very small photoluminescent gold nanoparticles for multimodality biomedical imaging.

An original synthesis method based on X-ray irradiation produced gold nanoparticles (AuNPs) with two important properties for biomedical research: intense visible photoluminescence and very high accumulation in cancer cells. The nanoparticles, coated with MUA (11-mercaptoundecanoid acid), are very small (1.4 nm diameter); the above two properties are not present for even slightly larger sizes.

Gold nanoparticles as high-resolution X-ray imaging contrast agents for the analysis of tumor-related micro-vasculature.

Background: Angiogenesis is widely investigated in conjunction with cancer development, in particular because of the possibility of early stage detection and of new therapeutic strategies. However, such studies are negatively affected by the limitations of imaging techniques in the detection of microscopic blood vessels (diameter 3-5 μm) grown under angiogenic stress. We report that synchrotron-based X-ray imaging techniques with very high spatial resolution can overcome this obstacle, provided that suitable contrast agents are used.

Complete microscale profiling of tumor microangiogenesis: a microradiological methodology reveals fundamental aspects of tumor angiogenesis and yields an array of quantitative parameters for its characterization.

Complete profiling would substantially facilitate the fundamental understanding of tumor angiogenesis and of possible anti-angiogenesis cancer treatments. We developed an integrated synchrotron-based methodology with excellent performances: detection of very small vessels by high spatial resolution (~1 μm) and nanoparticle contrast enhancement, in vivo dynamics investigations with high temporal resolution (~1 ms), and three-dimensional quantitative morphology parametrization by computer tracing. The smallest (3-10 μm) microvessels were found to constitute >80% of the tumor vasculature and exhibit many structural anomalies.

One-pot tuning of Au nucleation and growth: from nanoclusters to nanoparticles.

We describe a simple and effective method to obtain colloidal surface-functionalized Au nanoparticles. The method is primarily based on irradiation of a gold solution with high-flux X-rays from a synchrotron source in the presence of 11-mercaptoundecanoic acid (MUA). Extensive tests of the products demonstrated high colloidal density as well as excellent stability, shelf life, and biocompatibility.

Detecting small lung tumors in mouse models by refractive-index microradiology.

Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur.

Functional histology of glioma vasculature by FTIR imaging.

Fourier-transform infrared (FTIR) imaging has been used to investigate brain tumor angiogenesis using a mice solid tumor model and bare-gold (∅ 25 nm) or BaSO(4) (∅ 500 nm) nanoparticles (NP) injected into blood vasculature. FTIR images of 20-μm-thick tissue sections were used for chemical histology of healthy and tumor areas. Distribution of BaSO(4)-NP (using the 1,218-1,159 cm(-1) spectral interval) revealed clearly all details of blood vasculature with morphological abnormalities of tumor capillaries, while Au-NP (using the 1,046-1,002 cm(-1) spectral interval) revealed also diffusion properties of leaky blood vessels.

Imaging the cellular uptake of tiopronin-modified gold nanoparticles.

Well-dispersed gold nanoparticles (NP) coated with tiopronin were synthesized by X-ray irradiation without reducing agents. High-resolution transmission electron microscopy shows that the average core diameters of the NPs can be systematically controlled by adjusting the tiopronin to Au mole ratio in the reaction. Three methods were used to study the NP uptake by cells: quantitative measurements by inductively coupled plasma mass spectrometry, direct imaging with high lateral resolution transmission electron microscopy and transmission X-ray microscopy.

Quantitative analysis of nanoparticle internalization in mammalian cells by high resolution X-ray microscopy.

Background: Quantitative analysis of nanoparticle uptake at the cellular level is critical to nanomedicine procedures. In particular, it is required for a realistic evaluation of their effects. Unfortunately, quantitative measurements of nanoparticle uptake still pose a formidable technical challenge.

Detection of collagens in brain tumors based on FTIR imaging and chemometrics.

Fourier transform infrared (FTIR) imaging has been used as a molecular histopathology tool on brain tissue sections after intracranial implantation and development of glioma tumors. Healthy brain tissue (contralateral lobe) as well as solid and diffuse tumor tissues were compared for their collagen contents. IR spectra were extracted from IR images for determining the secondary structure of protein contents and compared to pure product spectra of collagens (types I, III, IV, V, and VI).

One-pot synthesis of AuPt alloyed nanoparticles by intense x-ray irradiation.

We synthesized AuPt alloyed nanoparticles in colloidal solution by a one-pot procedure based on synchrotron x-ray irradiation in the presence of PEG (polyethylene glycol). The exclusive presence of alloyed nanoparticles with fcc structure was confirmed by several different experiments including UV-vis spectroscopy, x-ray diffraction (XRD) and transmission electron microscopy (TEM). The composition of the AuPt alloyed nanoparticles can be varied in a continuous fashion by simply varying the feed ratios of Au and Pt precursors.

Tailored Au nanorods: optimizing functionality, controlling the aspect ratio and increasing biocompatibility.

Monodisperse gold nanorods with high aspect ratio were synthesized by x-ray irradiation. Irradiation was first used to stimulate the creation of seeds. Afterward, nanorod growth was stimulated either by chemical reduction or again by x-ray irradiation.

Synchrotron microangiography studies of angiogenesis in mice with microemulsions and gold nanoparticles.

We present an effective solution for the problem of contrast enhancement in phase-contrast microangiography, with the specific objective of visualising small (<8 microm) vessels in tumor-related microangiogenesis. Different hydrophilic and hydrophobic contrast agents were explored in this context. We found that an emulsified version of the hydrophobic contrast agents Lipiodol provides the best contrast and minimal distortion of the circulation and vessel structure.

Enhancement of cell radiation sensitivity by pegylated gold nanoparticles.

Biocompatible Au nanoparticles with surfaces modified by PEG (polyethylene glycol) were developed in view of possible applications for the enhancement of radiotherapy. Such nanoparticles exhibit preferential deposition at tumor sites due to the enhanced permeation and retention (EPR) effect. Here, we systematically studied their effects on EMT-6 and CT26 cell survival rates during irradiation for a dose up to 10 Gy with a commercial biological irradiator (E(average) = 73 keV), a Cu-Kalpha(1) x-ray source (8.

Enhanced x-ray irradiation-induced cancer cell damage by gold nanoparticles treated by a new synthesis method of polyethylene glycol modification.

We explored a very interesting gold nanoparticle system-pegylated gold in colloidal solution-and analyzed its uptake by mice colorectal adenocarcinoma CT26 tumor cells and the impact on the cell's response to x-ray irradiation. We found that exposure to polyethylene glycol (PEG) modified ('pegylated') 4.7 ± 2.