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Refereed/Peer-reviewed 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. These fluctuations are driven by the dynamic movement of subcellular structures including the cytoskeleton and inherently associated with the biological processes involved in cell invasion within tissues. It is experimentally demonstrated that the optical cellular micromotion correlates with tumor cells motility and invasiveness both at the population and single-cell levels. In addition, the optical cellular micromotion significantly reduced upon treatment with migrastatic drugs that inhibit tumor cell invasion. These results demonstrate that micromotion measurements can rapidly and non-invasively determine the invasive behavior of single tumor cells within tissues, yielding a new and powerful tool to assess the efficacy of approaches targeting tumor cell invasiveness.

This study analyzes how the characters in Lee Unkrich and Adrian Molina’s animated film Coco, mainly Mamá Imelda, Héctor, and Miguel, manage their emotional responses when they are facing loss, bereavement, or other significant changes in their lives. The study uses Elisabeth Kübler-Ross’s five-stage model of grief to analyze how these characters go through the grieving process. Moreover, in order to suggest how those who are grieving can enter into positive states of mind, the study expands on Kübler-Ross’s original model by incorporating a positive mindset of hope. In dialogue with Unkrich and Molina’s film, the study uses Kübler-Ross’s ideas to explore coping mechanisms that can help manage difficult times in life, while also suggesting the benefits of maintaining a positive mindset through hope.

Measuring tumour cell invasiveness through three-dimensional (3D) tissues, particularly at the single cell level, can provide important mechanistic understanding and assist in identifying therapeutic targets of tumour invasion. However, current experimental approaches, including standard in vitro invasion assays, have limited physiological relevance and offer insufficient insight about the vast heterogeneity in tumour cell migration through tissues. To address these issues, here we report on the concept of optical cellular micromotion, where digital holographic microscopy (DHM) is used to map the optical thickness fluctuations at sub-micron scale within single cells. These fluctuations are driven by the dynamic movement of subcellular structures including the cytoskeleton and inherently associated with the biological processes involved in cell invasion within tissues. We experimentally demonstrate that the optical cellular micromotion correlates with tumour cells motility and invasiveness both at the population and single cell levels. In addition, the optical cellular micromotion significantly reduced upon treatment with migrastatic drugs that inhibit tumour cell invasion. These results demonstrate that micromotion measurements can rapidly and non-invasively determine the invasive behaviour of single tumour cells within tissues, yielding a new and powerful tool to assess the efficacy of approaches targeting tumour cell invasiveness.Significance StatementTumour cells invasion through tissues is a key hallmark of malignant tumour progression and its measurement is essential to unraveling biological processes and screening for new approaches targeting cell motility. To address the limitations of current approaches, we demonstrate that sub-micron scale mapping of the dynamic optical thickness fluctuations within single cells, referred to as optical cellular micromotion, correlates with their motility in ECM mimicking gel, both at the population and single cell levels. We anticipate that 3D optical micromotion measurement will provide a powerful new tool to address important biological questions and screen for new approaches targeting tumour cell invasiveness.

The therapeutic ratio of radiotherapy is limited by acute or chronic side effects with often severe consequences to patients. The microvasculature is a central player involved in both tumor responses and healthy tissue/organ radiological injuries. However, current preclinical vascular models based on 2D culture offer only limited radiobiological insight due to their failure in recapitulating the 3D nature experienced by endothelial cells within the human microvasculature. To address this issue, the use of a3D microvasculature-on-a-chip microfluidic technology is demonstrated in radiobiological studies. Within this vasculogenesis model a perfusable network that structurally mimics the human microvasculature is formed and the biological response to ionizing radiation including cellular apoptosis,vessel tight adherens junction breakage, DNA double strand break,and repair is systematically investigated. In comparison to cells grownin a 2D environment, human umbilical vein endothelial cells in the 3Dmicrovasculature-on-a-chip displays significant differences in biological responses, especially at high X-ray dose. This data confirms the feasibility of using microvascular-on-a-chip models for radiobiological studies.Such vasculogenesis models have strong potential to yield more accurate prediction of healthy tissue responses to ionizing radiation as well as to guide the development of risk-reducing strategies to prevent radiation-induced acute and long-term side-effects. Refereed/Peer-reviewed

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 = 2.5) as cladding liquid is accomplished using dielectrophoresis (DEP) that attracts and deforms the core liquid with the greater permittivity to occupy the region of strong electric field provided by Teflon-coated ITO electrodes between parallel glass plates. Instead of continuously flowing core and cladding liquids along a physical microchannel, the DEP-formed L(2) optical waveguide guides light in a stationary virtual microchannel that requires liquids of limited volume without constant supply and creates stable liquid/liquid interfaces for efficient light guidance in a simply fabricated microfluidic device. We designed and examined (1) stationary and (2) moving L(2) optical waveguides on the parallel-plate electromicrofluidic platform. In the stationary L-shaped waveguide, light was guided in a GBL virtual microchannel core for a total of 27.85 mm via a 90° bend (radius 5 mm) before exiting from the light outlet of cross-sectional area 100 μm × 100 μm. For the stationary spiral waveguide, light was guided in a GBL core containing Rhodamine 6G (R6G, 1 mM) and through a series of 90° bends with decreasing radii from 5 mm to 2.5 mm. With the stationary straight waveguide, the propagation loss was measured to be 2.09 dB cm(-1) in GBL with R6G (0.01 mM). The moving L-shaped waveguide was implemented on a versatile electromicrofluidic platform on which electrowetting and DEP were employed to generate a precise GBL droplet and form a waveguide core. On sequentially applying appropriate voltage to one of three parallel L-shaped driving electrodes, the GBL waveguide core was shifted; the guided light was switched at a speed of up to 0.929 mm s(-1) (switching period 70 ms, switching rate 14.3 Hz) when an adequate electric signal (173.1 VRMS, 100 kHz) was applied.

This paper aimed to explore the effect of using YouTube as a supplementary material with EFL college students. The research intended to reveal the improvement of the students’ listening comprehension after the 5-week treatments—students participating in this study are all Taiwanese, age from 18-20, with a high intermediate level of proficiency in English. They were all in the same class and were exposed under the multimedia (YouTube) learning environment. However, students were obliged to finish the pre-test and post-tests. Moreover, the questionnaire was offered to them in order to know the perceptions and reflections of students with integrating YouTube into courses as well. In this research, paired T-Test was used to find out if there was a significant difference that exists before and after the treatments, also validate the pre-specified result. It was suggested that after training in the combination of the computer-assisted learning technique and traditional pedagogy, students performed better on the listening comprehension test than without the treatment before.

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. This is especially relevant to organs-on-chip models which allow for fine control of the culture environment. In this study, the effects of the FSS on Caco-2 cell monolayers were systematically determined using a microfluidic device based on Hele-Shaw geometry. This approach allowed fora physiologically relevant range of FSS (from ∼0 to 0.03 dyn/cm2) to be applied to the cells within a single device. Exposure to microfluidic FSS induced significant phenotypical and functional changes in Caco-2 cell monolayers as compared to cells grown in static conditions. The application of FSS significantly altered the production of mucus, expression of tight junctions, vacuolization, organization of cytoskeleton, formation of microvilli, mitochondrial activity and expression of cytochrome P450. In the context of the intestinal epithelium,this detailed understanding of the effects of the FSS will enable the realization of in vitro organs-on-chip models with well-defined and tailored characteristics to a specific purpose, including for drug and nanoparticle absorption studies. The Hele-Shaw approach used in this study could be readily applied to other cell types and adapted for a wide range of physiologically relevant FSS. Refereed/Peer-reviewed

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. Here, we used FTIR imaging to characterize collagen content changes in growing glioma tumors. We could determine that C6-derived solid tumors presented high content of triple helix after 8–11 days of growth (typical of collagen fibrils formation; 8/8 tumor samples; 91 % of total variance), and further turned to larger α-helix (days 12–15; 9/10 of tumors; 94 % of variance) and β-turns (day 18–21; 7/8 tumors; 97 % of variance) contents, which suggest the incorporation of non-fibrillar collagen types in ECM, a sign of more and more organized collagen scaffold along tumor progression. The growth of tumors was also associated to the level of collagen produced (P

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. The small MUA-AuNPs are non-cytotoxic (except for very high concentrations) and do not interfere with cancer cell proliferation. Multimodality imaging using visible light fluorescence and X-ray microscopy is demonstrated by tracing the nanoparticle-loaded tumor cells. (C) 2012 Elsevier Inc. All rights reserved.

article i nfo 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 withexcellent performances: detection of very small vessels by high spatialresolution (~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) microves- sels were found to constitute >80% of the tumor vasculature and exhibit many structural anomalies. Practical applications are presented, including vessel microanalysis in xenografted tumors, monitoring the effects of anti-angiogenetic agents and in vivo detection of tumor vascular rheological properties.

We demonstrate that, with appropriate staining, high-resolution X-ray microscopy can image complicated tissue structures—cerebellum and liver—and resolve large or small amounts of Au nanoparticles in these tissues. Specifically, images of tumor tissue reveal high concentrations of accumulated Au nanoparticles. PEG (poly(ethylene glycol)) coating is quite effective in enhancing this accumulation and significantly modifies the mechanism of uptake by reticuloendothelial system (RES) organs. Refereed/Peer-reviewed

We successfully demonstrate the in situ formation by X-ray irradiation induced polymerization of a three-dimensional (3D) hydrogel based on poly(ethylene glycol) (PEG) diacrylate (PEG DA), with the option of heparin incorporation to enhance cell adhesion. The polymerization reaction can be completed in tens of seconds, thanks to the fast and uniform X-ray induced process. Eliminatin gpolymerization initiators and the residual unreacted monomers improves the biocompatibility and stability of the hydrogel. The photopolymerization mechanism can be locally controlled by usinga trimmed or a focused X-ray beam to allow precise in vivo administration deep in the tissue, without surgery. We also demonstrate that photopolymerized hydrogels containing polyethylenimine (PEI)/nucleic acid (DNA or small interfering RNA, siRNA) nanoparticles (NPs) can deliver such nanoparticles. The hydrogel is biocompatible with mice and is not toxic to epithelial cells. Refereed/Peer-reviewed

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. Specific tests with X-ray diffraction, UV-visible spectrometry, visible microscopy, Fourier transform infrared spectroscopy, dark-field visible-light scattering microscopy, and transmission electron microscopy demonstrated that MUA, being an effective surfactant, not only allows tunable size control of the nanoparticles, but also facilitates functionalization. The nanoparticle sizes were 6.45 ± 1.58, 1.83 ± 1.21, 1.52 ± 0.37 and 1.18 ± 0.26 nm with no MUA and with MUA-to-Au ratios of 1:2, 1:1, and 3:1. The MUA additionally enabled functionalization with l-glycine. We thus demonstrated flexibility in controlling the nanoparticle size over a large range with narrow size distribution. Refereed/Peer-reviewed

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. The results confirmed that the NP internalization mostly occurred via endocytosis and concerned the cytoplasm. The particles, in spite of their small sizes, were not found to arrive inside the cell nuclei. The synthesis without reducing agents and solvents increased the biocompatibility as required for potential applications in analysis and biomedicine in general Refereed/Peer-reviewed

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). Multivariate statistical analyses of variance and correspondence factorial analysis were performed to differentiate healthy and tumor brain tissues as well as their classification according to their secondary structure profiles. Secondary structure profiles revealed that no collagen was present in healthy tissues; they are also significantly different from solid and diffuse tumors (p

The spatial distribution of X-ray synthesized, PEG coated Au nanoparticles in cancer-bearing mice and their time dependent accumulation were investigated with inductive coupled plasma – optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM) and histological imaging. The results conclusively demonstrate that the particles strongly accumulate in tumor regions; up to ∼25 times more than in normal muscle tissue. This accumulation increases with the time after injection for up to ∼12 h in tumor, spleen and liver tissues, whereas for most non-tumor regions it saturates or decreases (blood, lung, brain, heart, and kidney). The impact of this result is discussed with special emphasis on passive targeted drug delivery and could also be used for the delineation and early-stage imaging of small tumors. Refereed/Peer-reviewed

Au/TiO2 nanocomposite particles were synthesized by a method based on intense X-ray irradiation without adding any reducing agent or stabilizer. The nanocomposite exhibits promising photocatalytic and biological properties at physiologically relevant concentration ([Au] = 0.028 mM, [TiO2] = 0.5 mM). The structure and photocatalysis were examined by X-ray diffraction, electron microscopy and ultraviolet-visible spectroscopy demonstrating that gold nanoparticles of 2-5 nm size were successfully deposited on TiO2 nanoparticle surfaces. The nanocomposite exhibited good colloidal stability within a typical cellular environment and was nontoxic to cancer cell according to evaluations under controlled conditions. The Au/TiO2 nanoparticles were also found to enhance the photocatalytic efficiency of UV radiation and even more that of X-ray radiation. In vitro studies indicated that the cell-killing effect under X-ray irradiation is more pronounced with the addition of Au/TiO2 nanoparticles than of bare TiO2 nanoparticles. (C) 2009 Elsevier B.V. All rights reserved.

Colloidal Ag nanoparticles were formed by X-ray irradiation in the presence of a polymer. This new synthesis method is simple, rapid and leads to a high production yield. Compared to the citrate-reduced Ag colloidal, polymer-protected Ag nanoparticles are smaller in size and more stable—and therefore suitable for biomedical application—as verified by TEM observation, XAFS measurement and optical characterization. Ag nanoparticles so produced were also visualized in solution and in real time by a visible light microscope based on dark field light scattering. The color-derived size and distribution of Ag nanoparticles correlates well with the hydrodynamic size data.

Objective To evaluate the cytotoxicity of nickel-based alloy surfaces after nitride film coatings. Methods A total of 120 disc-shaped specimens (1.5 × 12.0 mm) were prepared from nickel (Ni) alloy ingots and metallurgically ground with silicon carbide (SiC) sandpaper to 1200 grit and used as the ground group. Ninety specimens from the ground group were selected and further polished with 1.0 μm aluminum powder slurry and assigned as the polished group. Titanium nitride (TiN) and titanium–aluminum nitride (TiAlN) film coatings were deposited onto 30 polished specimens each by a reactive radio frequency magnetron sputter deposition system and used as coated groups, respectively. The morphological changes and cytoskeleton of tested human gingival fibroblasts were observed using fluorescence microscopy at 3 h and 24 h time periods, respectively. An MTT assay was used to assess cell viability at 24 h. The results were statistically analyzed (n = 5, ANOVA, Scheffe’, p Results After 3 h of incubation, cells began to spread on the test surfaces. Spindle-shaped fibroblasts with well-developed cytoskeleton and distinct actin fibers were observed at the 24 h incubation point on the polished and coated specimens. Results of the MTT assay revealed that the TiN and TiAlN film coated groups were significantly higher in cell proliferation and viability than the polished and control groups (p Significance The biocompatibilty of Ni-based alloy was increased significantly after nitride film coating.

Reductant, stabilizer-free colloidal gold solutions were fabricated by a new room-temperature synchrotron X-ray irradiation method. The influence of process parameters such as the pH value and the exposure time on the structure of gold nanoparticles was investigated. The mechanisms underlying the X-ray-triggered reduction of gold ions and the formation of gold clusters are discussed in detail. The X-ray irradiation derived highly concentrated gold nanoparticles are readily to be re-dispersed and possess suitable colloidal stability within cellular environment. The characterization included a study of the possible cytotoxicity for the EMT-6 tumor cell line: the negative results indicate that the gold clusters produced with our approach are biocompatible.

The formation of colloidal unmodified (naked) gold nanoparticles is investigated by irradiation of a precursor solution with X-rays from a synchrotron source. An interesting morphological evolution as a function of exposure time, from cross-linked network-like structure to individual particles, has been discovered. The particle size decreased with the exposure time and was influenced by the ionic strength of the precursor solution. Contrary to gamma-ray exposure, an OH radical scavenger was not required for cluster formation.

Background Nanoparticles can be used for targeted drug delivery, in particular for brain cancer therapy. However, this requires a detailed analysis of nanoparticles from the associated microvasculature to the tumor, not easy because of the required high spatial resolution. The objective of this study is to demonstrate an experimental solution of this problem, based in vivo and post-mortem whole organ imaging plus nanoscale 3-dimensional (3D) X-ray microscopy. Results The use of gold nanoparticles (AuNPs) as contrast agents paved the way to a detailed high-resolution three dimensional (3D) X-ray and fluorescence imaging analysis of the relation between xenografted glioma cells and the tumor-induced angiogenic microvasculature. The images of the angiogenic microvessels revealed nanoparticle leakage. Complementary tests showed that after endocytotic internalization fluorescent AuNPs allow the visible-light detection of cells. Conclusions AuNP-loading of cells could be extended from the case presented here to other imaging techniques. In our study, they enabled us to (1) identify primary glioma cells at inoculation sites in mice brains; (2) follow the subsequent development of gliomas. (3) Detect the full details of the tumor-related microvasculature; (4) Finding leakage of AuNPs from the tumor-related vasculature, in contrast to no leakage from normal vasculature. Electronic supplementary material The online version of this article (doi:10.1186/s12951-015-0140-2) contains supplementary material, which is available to authorized users.

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 CNCmachining center, containing arrays of 3D convex micropillars withsize ranging from 150 μm to 600 μm. Microscopic imaging of themicropillars machined on the mold showed smooth, curved microfeatures of a dramatic 3D shape. Agarose microwells could be easily replicated from the metallic molds. EMT-6 tumor cells seeded in the primary macrowell sedimented efficiently to the bottom of the concave microwells and formed multicellular spheroidswithin 48 h. Dense and homogeneous multicellular spheroids were obtained after 10 days of culture, confirming the suitability ofthe proposed approach. To facilitate long term spheroid culture and reliable on-chip drug assay, polydimethylsiloxane microwells were also replicated from the metallic molds. A solvent swelling method was adapted and optimized to Pluronic F127 towardsphysically entrapping the block copolymer molecules within the polydimethylsiloxane network and in turn to improve long termcell-binding resistance. Homogeneous multicellular spheroids were efficiently formed in the concave microwells and on-chip drug assays could be reliably carried out using curcumin as a model anti-cancer drug. Advanced micromachining provides an excellent technological solution to the fabrication of high quality concave microwells. Refereed/Peer-reviewed

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 bind- ing affinity to lymphoid cells in the popliteal and axillary lymph nodes in comparison to non-targeted nanoparticles. Refereed/Peer-reviewed

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. Results We tested different contrast agents based on gold nanoparticles (AuNPs) for the detection of cancer-related angiogenesis by synchrotron microradiology, microtomography and high resolution X-ray microscopy. Among them only bare-AuNPs in conjunction with heparin injection provided sufficient contrast to allow in vivo detection of small capillary species (the smallest measured lumen diameters were 3-5 μm). The detected vessel density was 3-7 times higher than with other nanoparticles. We also found that bare-AuNPs with heparin allows detecting symptoms of local extravascular nanoparticle diffusion in tumor areas where capillary leakage appeared. Conclusions Although high-Z AuNPs are natural candidates as radiology contrast agents, their success is not guaranteed, in particular when targeting very small blood vessels in tumor-related angiography. We found that AuNPs injected with heparin produced the contrast level needed to reveal--for the first time by X-ray imaging--tumor microvessels with 3-5 μm diameter as well as extravascular diffusion due to basal membrane defenestration. These results open the interesting possibility of functional imaging of the tumor microvasculature, of its development and organization, as well as of the effects of anti-angiogenic drugs.

We report recent advances in hard-x-ray optics—including record spatial resolution—and in staining techniques that enable synchrotron microradiology to produce neurobiology images of quality comparable to electron and visible microscopy. In addition, microradiology offers excellent penetration and effective three-dimensional detection as required for many neuron studies. Our tests include tomographic reconstruction based on projection image sets.

Gold nanoparticles (GNPs) are intravenously administered to mice. Deposition at the pilosebacious unit and whiskers is visualized with X-ray fl uorescence after 30 minutes and 14 days. After 30 minutes the dermal papilla, bulge region, and root sheath all contain NPs. GNPs are driven externally out from follicles, counteractive to transfollicular delivery. After 14 days, gold bands in hairs refl ect pharmacokinetic profi les indicating blood concentration kinetics. Elimination rate constants infer half-lives from 3 hairs from an individual mouse within reasonable agreement (6.08, 7.15, and 8.66 hours). 3D reconstruction of NP distributions with confocal microscopy identifi es aggregates within the medullary canal. Intermittent NP deposition continues randomly over the two week period demonstrating prolonged NP mobility in vivo. NPs are still retained at the hair bulb after 14 days. The observations further account for the excretory mechanisms of NPs and their behavior in the pilosebacous unit, and demonstrate monitoring pharmacokinetic behavior in individual animals. Refereed/Peer-reviewed

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. A direct comparison with pathology optical images illustrates the effectiveness of this approach Refereed/Peer-reviewed

Our experimental results demonstrate that full-field hard-X-ray microscopy is finally able to investigate the internal structure of cells in tissues. This result was made possible by three main factors: the use of a coherent (synchrotron) source of X-rays, the exploitation of contrast mechanisms based on the real part of the refractive index and the magnification provided by high-resolution Fresnel zone-plate objectives. We specifically obtained high-quality microradiographs of human and mouse cells with 29 nm Rayleigh spatial resolution and verified that tomographic reconstruction could be implemented with a final resolution level suitable for subcellular features. We also demonstrated that a phase retrieval method based on a wave propagation algorithm could yield good subcellular images starting from a series of defocused microradiographs. The concluding discussion compares cellular and subcellular hard-X-ray microradiology with other techniques and evaluates its potential impact on biomedical research. (C) 2012 Elsevier Inc. All rights reserved.

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 ? 2.6?nm gold nanoparticles synthesized by a novel synchrotron-based method enhances the response of CT26 cells to x-ray irradiation. Transmission electron microscopy (TEM) and confocal microscopy revealed that substantial amounts of such nanoparticles are taken up and absorbed by the cells and this conclusion is supported by quantitative induced coupled plasma (ICP) results. Standard tests indicated that the internalized particles are highly biocompatible but strongly enhance the cell damage induced by x-ray irradiation. Synchrotron radiation Fourier transform infrared (SR-FTIR) spectromicroscopy analyzed the chemical aspects of this phenomenon: the appearance of C = O stretching bond spectral features could be used as a marker for cell damage and confirmed the enhancement of the radiation-induced toxicity for cells.

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 BaSO4 (∅ 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 BaSO4-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. Diffusion of Au-NP out of vascular space reached 64 ± 29 μm, showing the fenestration of “leaky” tumor blood vessels, which should allow small NP (

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. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm3 with accuracy better than 1 × 10−3 mm3. This level of performance is currently suitable for animal studies, while further developments are required for clinical application. Refereed/Peer-reviewed

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 (8.048 keV), a monochromatized synchrotron source (6.5 keV), a radio-oncology linear accelerator (6 MeV) and a proton source (3 MeV). The percentage of surviving cells after irradiation was found to decrease by approximately 2-45% in the presence of PEG-Au nanoparticles ([Au] = 400, 500 or 1000 microM). The cell survival rates decreased as a function of the dose for all sources and nanoparticle concentrations. These results could open the way to more effective cancer irradiation therapies by using nanoparticles with optimized surface treatment. Difficulties in applying MTT assays were also brought to light, showing that this approach is not suitable for radiobiology.

We present an effective solution for the problem of contrast enhancement in phase-contrast microangiography, with the specific objective of visualising small(

This paper reports the design of an optical waveguide in which both the core and cladding structures are liquids. The waveguide is formed by driving a high permittivity core liquid in a low permittivity cladding liquid through dielectrophoresis (DEP). The DEP-driven core liquid preserves the advantage of the smooth liquid-liquid interface [3–4], while the stationary core and cladding liquid would eliminate scattering losses caused by liquid flowing. Because the core liquid is defined by the electric field, arbitrary two dimensional shapes of the waveguide can be achieved by voltage application on designed electrode patterns.

We report a technique for detection of sub‐cellular organelles and proteins with hard x‐ray microscopy. Several metals were used for enhancing contrast for x‐ray microscopy. Osmium tetroxide provides an excellent stain for lipid and can delineate cell membrane. Uranyl acetate has high affinity for nucleotide and can stain nucleus. Immunolocalization of specific proteins and sub‐cellular organelles was achieved by 3’3 diaminobenzidine (DAB) with nickel enhancement and nanogold‐conjugated secondary antibody with silver enhancement. The x‐rays emitted from synchrotron source was monochromatized by double crystal monochromator, the photon energy was fixed at 8 keV to optimize the focusing efficiency of the zone plates. The estimated resolution is about 60 nm. When compared with visible light and conventional confocal microscopy, the X‐ray microscopy provides a superior resolution to both conventional optical microscopes.

We report the analysis of a reducing-agent-free synthetic method based on intense X-ray irradiation in the presence of 11-mercaptoundecanoic acid (MUA) and their application in biomedical imaging. The method is very effective in controlling the size and size distribution of Au nanoparticles in colloidal solutions: gold nanoparticles (AuNPs) as small as ∼1.2 ± 0.25 nm are synthesized in a one-pot irradiation procedure without reducing agents. We found two coexisting properties of these small AuNPs: a strong visible fluorescence and very high accumulation in cells, which enabled a new type of multimodality imaging using X-ray and visible light microscopies. These properties come as a direct consequence of the precise size control; specifically, they exist only when the particle size is smaller than ∼1.4 nm. We found that this process critically depends on several parameters including the solution pH, the solution temperature and the irradiation time. Most important is the fact that the increase of the irradiation time is not necessarily beneficial, since an optimum value exists to obtain small particles with a narrow size distribution. The 1.4 nm AuNPs are not toxic and significantly accumulate in tumor tissues in animal tests, as confirmed by X-ray imaging and fluorescence microscopy. This biodistribution could open the way for the use of these nanoparticles in X-ray imaging. Refereed/Peer-reviewed

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. The nanoparticles exhibited colloidal stability and biocompatibility, important for potential applications. Refereed/Peer-reviewed

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. In the last case, the entire process took place without reducing agents. The shape of the final products could be controlled by modulating the intensity of the x-ray irradiation during the seed synthesis. In turn, the nanorod aspect ratio determines the absorption wavelength of the nanorods that can thus be optimized for different applications. Likewise, the aspect ratio influences the uptake of the nanorods by HeLa cells. Refereed/Peer-reviewed

Substantial improvements in the nanofabrication and characteristics of gold Fresnel zone plates yielded unprecedented resolution levels in hard-x-ray microscopy. Tests performed on a variety of specimens with 8-10keV photons demonstrated a first-order lateral resolution below 40nm based on the Rayleigh criterion. Combined with the use of a phase contrast technique, this makes it possible to view features in the 30nm range; good-quality images can be obtained at video rate, down to 50ms/frame. The important repercussions on materials science, nanotechnology, and the life sciences are discussed.