Bioluminescence, chemiluminescence and fluorescence imaging, January 2004-May 2006 literature.
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Diagnostic Imaging↗
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Results for “Fluorescence imaging”
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Mapping photogenerated radicals in thin polymer films: fluorescence imaging using a prefluorescent radical probe.
Prefluorescent radical probes, in which fluorescence is activated by radical trapping, and photoinitiators were used to detect radical generation in polymer films using fluorescence spectroscopy and microscopy. Prefluorescent radical probes are the foundation of a fluorescence imaging system for polymer films, that may serve both as a mechanistic tool in the study of photoinitiated radical processes in polymer films and in the preparation of functional fluorescent images.
Journal Article↗
Mapping of a particular element using an absorption edge with an X-ray fluorescence imaging microscope.
An X-ray fluorescence imaging microscope with a Wolter-type objective mirror (magnification: 13) has been constructed at beamline 39XU of SPring-8. Monochromatic X-rays (DeltaE/E approximately 10(-4)) in the energy range 6-10 keV were used for X-ray fluorescence excitation of the specimens. Using two monochromatic X-rays above and below the absorption edge of a particular element, a two-dimensional image of the element could be obtained. As a result, two-dimensional element mapping of the test specimens (Cu, Co, Ni, Fe and Ti wires) and constituent minerals (Fe, Mn and Ti) of a rock specimen (a piemontite-quartz schist) became possible.
Journal Article↗
Time-resolved fluorescent imaging of glucose.
A method for the fluorescent imaging of glucose is described that is based on the detection of enzymatically produced hydrogen peroxide, using the europium(III) tetracycline complex as the fluorescent probe incorporated into a hydrophilic polymer layer. Coadsorption of glucose oxidase (GOx) makes these sensor layers respond to the hydrogen peroxide produced by the GOx-assisted oxidation of glucose. The hydrogel layers are integrated into a 96-microwell plate for a parallel and simultaneous detection of various samples. Glucose is visualized by means of time resolved luminescence lifetime imaging. Unlike in previous methods, the determination of H2O2 does not require the addition of peroxidase or a catalyst to form a fluorescent product. The lifetime-based images obtained are compared with conventional fluorescence intensity-based methods with respect to sensitivity and the dynamic range of the sensor layer. The main advantages provided by this sensing scheme for H2O2 include reversibility, applicability at neutral pH, and the straightforwardness of the transducer system and the imaging device.
Biosensing Techniques↗
Dendrimer-based nanoprobe for dual modality magnetic resonance and fluorescence imaging.
A novel PAMAM dendrimer-based nanoprobe for dual magnetic resonance and fluorescence imaging modalities was synthesized. Fluorescence studies revealed that Gd(III) complexation to the probe has no effect on the quantum yield; however, increases in the dye content resulted in partial quenching. The potential of the new nanoprobe, G6-(Cy5.5)(1.25)(1B4M-Gd)(145), as a dual modality imaging agent was demonstrated in vivo by the efficient visualization of sentinel lymph nodes in mice by both MRI and fluorescence imaging modalities.
Animals↗
New fluorescence imaging probe with high spatial resolution for in vivo applications.
A new fiberized fluorescence imaging probe is presented. This device can potentially be used for a wide range of biological or medical applications. By exploiting the chromatic aberrations of gradient index lenses, the excitation blue or near-UV excitation light is focused on the sample surface, while the red fluorescence signal is efficiently launched back to collecting fibers. The excitation fiber is single mode at the working wavelength so that a resolution of 5 microm is obtained over a scanning area of several square millimeters. Experimental fluorescence images are presented. They concern either self-fabricated fluorescent microsamples or views of leaves that constitute an example of biological tissues analysis. The probe can also be adapted for spectroscopic investigations.
Equipment Design↗
Laser-induced fluorescence imaging in localization of head and neck cancers.
Laser-induced fluorescence tumor imaging exploits the difference in tissue autofluorescence properties between normal and cancerous tissues. The effectiveness and reliability of fluorescence imaging with a lung imaging fluorescence endoscopy (LIFE) system for cancers in the head and neck were compared to those of white light endoscopy (WLE). Examinations by WLE and LIFE were conducted on 25 patients suspected for malignancy. Histologic diagnosis was confirmed by biopsy. Posttreatment evaluations were performed on 6 cancer patients identified by this study. By LIFE, all 16 cancerous lesions, including 2 occult cancers, were identified (100%), while WLE achieved only an 87.5% detection rate. LIFE (specificity 87.5%) was greatly helpful to WLE (specificity 50%) in differentiating inflammation from malignancy, though it failed to exclude granuloma. The results of this study suggest potential roles of LIFE in early detection, correct staging, and treatment evaluation of cancers in the head and neck.
Endoscopy↗
Phycobiliprotein-Fab conjugates as probes for single particle fluorescence imaging.
BACKGROUND AND METHODS: Single particle fluorescence imaging (SPFI) is a recently developed method that has provided a powerful approach to observing receptor movement and associations at high spatial resolution. It provides a noninvasive alternative to the existing biochemical techniques. It can also quantify and resolve molecular interactions at the cell surface at a nanometer scale. Probes that have been used in the past to study mobility and associations of cell surface receptors have many limitations. These include concerns about the specificity of the probes, the possibility that their size interferes with the receptor once bound to it, the nonuniform fluorescence, and the questionable stoichiometry. RESULTS: In this study, we have generated phycobiliprotein-Fab conjugates, and have shown that they are a significant advance on existing probes for SPFI studies. They are small in size, highly specific, highly fluorescent, of known stoichiometry, photostable, emit uniform fluorescence, and are generally well defined. CONCLUSIONS: It is highly important that when studying receptor mobility or associations, fully characterized probes are used. Phycoerythrin(PE)-Fab probes provide us with the perfect tool for SPFI, and a system with a wide range of applicability to study any cell surface receptor against which a monoclonal antibody exists.
Antibodies, Monoclonal↗
Laser irradiative tissue probed in situ by collagen 380-nm fluorescence imaging.
BACKGROUND AND OBJECTIVE: There is no ideal method to detect molecular changes in situ of laser-irradiated tissue without removing a section of tissue for histologic examination. A new method is reported to evaluate laser-induced thermal tissue damage in situ by using 380-nm native fluorescence imaging under 340-nm excitation. STUDY DESIGN/MATERIALS AND METHODS: Native fluorescence imaging was performed on laser irradiated bovine tendon tissue and compared with light illuminated photography and histology with picrosirius red F3BA stain. RESULTS AND CONCLUSION: The results indicate that a decrease in collagen fluorescence at 380 nm was observed in laser-induced thermally damaged tissues. The injured region of tissue defined by its fluorescence image coincided with an area defined by photography and histology.
Animals↗
Micro X-ray fluorescence imaging without scans: toward an element-selective movie.
Micro X-ray fluorescence imaging is a promising method for obtaining positional distribution on specific elements in a nondestructive manner. So far, the technique has usually been performed by a 2D positional scan of a sample against a collimated beam. However, the total measuring time can become quite long, since a number of scanning points are needed in order to obtain a high-quality image. The present report discusses a completely different way of performing imaging of elements much more quickly. A combination of grazing-incidence geometry using a rather wide beam and parallel optics for detecting X-rays can produce an X-ray fluorescence image with approximately 1 M pixels and with approximately 20-microm resolution in 1-2 min or less. The technique has the potential to open up new frontiers in X-ray imaging, particularly in element-selective movie applications.
Letter↗
Laser-induced fluorescence imaging and spectroscopy of GFP transgenic plants.
Green fluorescent protein (GFP) and other fluorescent protein bioreporters can be used to monitor transgenes in plants. GFP is a valuable marker for transgene presence and expression, but remote sensing instrumentation for stand-off detection has lagged behind fluorescent protein marker biotechnology. However, both biology and photonics are needed for the monitoring technology to be fully realized. In this paper, we describe laser-induced fluorescence imaging and laser-induced fluorescence spectroscopy of GFP-transgenic plants in ambient light towards the application of remote sensing of transgenic plants producing GFP.
Green Fluorescent Proteins↗
Quantitative fluorescence imaging approach for the study of polyploidization in hepatocytes.
We applied automatic quantitative fluorescence imaging of nuclear DNA to rat liver cells obtained from animals at various times after birth up to 3 months of age. We show that, in conditions best preserving the native cellular structures, DNA content measurements, performed on whole single cells in situ after Hoechst staining, were precise and accurate. Cells in the various ploidy and nuclearity classes could thus be identified correctly and their percentages were estimated on a total of 300 cells or more. DNA synthesis was shown to occur asynchronously in all ploidy and nuclearity classes around weaning time. Observation of the labeling patterns, after in vivo BrdU pulse and short-term culture (chase), showed that the cell cycle was shorter in diploid cells compared with cells undergoing polyploidization. These results show that the approach of fluorescence imaging is well suited to investigations on polyploidization mechanisms.
Age Factors↗
Fluorescence imaging of tracer distributions in soil profiles.
To evaluate and parametrize transport models for the vadose (partially water-unsaturated) zone, information about the spatial distributions of solutes is needed. We describe a technique for the simultaneous imaging of several fluorescent tracers in structured field soils. With this technique, we obtain information on local mixing under field conditions. Local dispersion is a decisive process that discriminates different flow regimes. The imaging device consists of a high-power xenon lamp and a sensitive charge coupled device (CCD) camera. The three fluorescent dyes Brilliant sulfaflavine (BF), Sulforhodamine B (SB), and Oxazine 170 (OX) were chosen as solute tracers for their spectroscopic properties and different sorption coefficients. We conducted a field experiment using these tracers and took images of their distribution in a vertical soil profile. The fluorescence images (1242 by 1152 pixels) were corrected for nonuniform lighting, changing surface roughness, and varying optical properties of the soil profile. The resulting two-dimensional relative concentration distributions were similar for BF and SB. The reason might be the fast transport regime, which prevents the establishment of sorption equilibria. According to its higher sorption coefficient, OX was more strongly retarded. In this paper, we show that the fluorescence imaging technique is a powerful tool for the in-situ investigation of transport processes of fluorescent solute tracers in soil profiles. Due to the high spatial resolution of the tracer concentration maps and the ability to detect the flow field characteristics of differently reactive tracers simultaneously under field conditions, this technique provides valuable experimental data for the test and development of theoretical models for heterogeneous solute transport in soils.
Adsorption↗
Improvement of transcutaneous fluorescent images with a depth-dependent point-spread function.
The point-spread function (PSF) for transcutaneous fluorescent imaging was obtained as an analytical solution in a closed form. It is applicable to cases in which the optical property of the image-blurring turbid medium is considered to be fairly homogeneous. We proposed a technique to improve a transcutaneous image by using depth-dependent PSF. Contrast of the fluorescent image was improved for depths of 1-15 mm in a scattering medium (micro(s)' = 1/mm). The visible depth was more than doubled with this technique. An experiment with a rat demonstrated considerable improvement of a transcutaneous image of the cerebral vein at a specified depth. The spread image of the heart was reduced to the correct size by use of the PSF with the actual depth of the heart.
Algorithms↗
Time-gated fluorescence imaging for the diagnosis of tumors in a murine model.
A system for time-gated fluorescence imaging was used to perform measurements on tumor-bearing mice treated with hematoporphyrin derivative (HpD). The aim of the study was to define the potential of this technique in the diagnosis of tumors by taking advantage of the long fluorescence lifetime of the exogenous dye with respect to the decay times of the natural fluorescence. After the administration of three different drug doses (5, 10 and 25 mg/kg body weight), fluorescence images were acquired at various uptake times (from 2 h to 10 d), to determine the best instrumental conditions and experimental procedure for the detection of tumors in the murine model considered. The optimal fluorescence contrast between the tumor area and the surrounding healthy tissue was found at 12 h after the administration of either 5 or 10 mg/kg HpD and was anticipated at 8 h for the highest drug dose. In this optimum condition, the tumor region could be identified even after the injection of 5 mg/kg HpD. A better fluorescence contrast was always obtained in 15 ns-delayed images with respect to synchronous ones.
Animals↗
Automatic multiparameter fluorescence imaging for determining lymphocyte phenotype and activation status in melanoma tissue sections.
A system has been developed that combines multiparameter fluorescence imaging and computer vision techniques to provide automatic phenotyping of multiple cell types in a single tissue section. This system identifies both the nuclear and cytoplasmic boundary of each cell. A routine based on the watershed algorithm has been developed to segment an image of Hoechst-stained nuclei with an accuracy of greater than 85%. Deformable splines initially positioned at the nuclear boundaries are applied to images of fluorescently labelled cell-surface antigens. The splines lock onto the peak fluorescence signal surrounding the cell, providing an estimate of the cell boundary. From measurements acquired at this boundary, each cell is classified according to antigen expression. The system has been piloted in biopsies from melanoma patients participating in a clinical trial of the antibody R24. Thin tissue sections have been stained with Hoechst and three different fluorescent antibodies to antigens that permit the typing and evaluation of activity of T-cells. Changes in the infiltrates evaluated by multiparameter imaging were consistent with results obtained by immunoperoxidase analysis. The multiparameter fluorescent technique enables simultaneous determination of multiple cell subsets and can provide the spatial relationships of each cell type within the tissue.
Antigens, CD↗
Near-field fluorescence imaging of single molecules with a resolution in the range of 10 nm.
We demonstrate fluorescence imaging of single molecules, by near-field scanning optical microscopy (NSOM), using the illumination-collection mode of operation, with an aperture probe. Fluorescence images of single dye molecules were obtained with a spatial resolution of 15 nm, which is smaller than the diameter of the aperture (20 nm) of the probe employed. Such super-resolution may be attributable to non-radiative energy transfer from the molecules to the coated metal of the probe since the resolution obtained in the case of conventional NSOM is limited to 30-50 nm due to penetration of light into the metal.
Journal Article↗
Digital background subtraction for fluorescence imaging.
A method of enhancing contrast in fluorescence imaging has been devised, based on real-time digital subtraction of a background video image from a signal-plus-background video image. Color filters are used to differentiate signal from background. The technique has been applied to detection of small tumors labeled with the tumor specific fluorescent drug hematoporphyrin derivative.
Biophysical Phenomena↗