Biological Imaging (biological + imaging)

Distribution by Scientific Domains

Selected Abstracts

Generic Strategy of Preparing Fluorescent Conjugated-Polymer-Loaded Poly(DL -lactide- co -Glycolide) Nanoparticles for Targeted Cell Imaging

Kai Li
Abstract A general strategy for the preparation of highly fluorescent poly(DL-lactide- co -glycolide) (PLGA) nanoparticles (NPs) loaded with conjugated polymers (CPs) is reported. The process involves encapsulation of organic-soluble CPs with PLGA using a modified solvent extraction/evaporation technique. The obtained NPs are stable in aqueous media with biocompatible and functionalizable surfaces. In addition, fluorescent properties of the CP-loaded PLGA NPs (CPL NPs) could be fine-tuned by loading different types of CPs into the PLGA matrix. Four types of CPL NPs are prepared with a volume-average hydrodynamic diameter ranging from 243 to 272,nm. The application of CPL NPs for bio-imaging is demonstrated through incubation with MCF-7 breast cancer cells. Confocal laser scanning microscopy studies reveal that the CPL NPs are internalized in cytoplasm around the nuclei with intense fluorescence. After conjugation with folic acid, cellular uptake of the surface-functionalized CPL NPs is greatly enhanced via receptor-mediated endocytosis by MCF-7 breast cancer cells, as compared to that for NIH/3T3 fibroblast cells, which indicates a selective targeting effect of the folate-functionalized CPL NPs in cellular imaging. The merits of CPL NPs, such as low cytotoxicity, high fluorescence, good photostability, and feasible surface functionalization, will inspire extensive study of CPL NPs as a new generation of probes for specific biological imaging and detection. [source]

Generic Method of Preparing Multifunctional Fluorescent Nanoparticles Using Flash NanoPrecipitation

Mustafa Akbulut
Abstract There is increased demand for nanoparticles with a high fluorescence yield that have the desired excitation wavelength, surface functionalization, and particle size to act as biological probes. Here, a simple, rapid, and robust method, Flash NanoPrecipitation (FNP), to produce such fluorescent nanoparticles is described. This process involves encapsulation of a hydrophobic fluorophore with an amphiphilic biocompatible diblock copolymer in a kinetically frozen state. FNP is used to produce nanoparticles ranging from 30 to 800,nm with fluorescence emission peaks ranging from, but not limited to, 370,nm to 720,nm. Such fluorescent nanoparticles remain stable in aqueous solutions, and, in contrast to soluble dyes, show no photobleaching. Fluorophores and drugs are incorporated into a single nanoparticle, allowing for simultaneous drug delivery and biological imaging. In addition, functionalization of nanoparticle surfaces with disease-specific ligands permits precise cell targeting. These features make FNP-produced fluorescent nanoparticles highly desirable for various biological applications. [source]

Functional IrIII Complexes and Their Applications

Zhu-qi Chen
Abstract Iridium complexes are drawing great interest because they exhibit high phosphorescence quantum efficiency. Extensive efforts have been devoted to the molecular design of ligands to achieve phosphorescent emission over a wide range of wavelengths that is compatible with many applications. In this research news article, we focus on materials design to improve the performance of phosphorescent IrIII complexes for organic light-emitting diodes (OLEDs), luminescence sensitizers, and biological imaging. [source]

Cationic Oligofluorene-Substituted Polyhedral Oligomeric Silsesquioxane as Light-Harvesting Unimolecular Nanoparticle for Fluorescence Amplification in Cellular Imaging

Kan-Yi Pu
A new bottom-up strategy is used to construct water-soluble organic/inorganic fluorescent unimolecular nanoparticles based on polyhedral oligomeric silsesquioxane (POSS) and conjugated oligoelectrolyte. Their high quantum yield, good cytocompatibility, and unique whole-cell permeability could serve as a light-harvesting energy donor to amplify the intracellular dye fluorescence for high-quality biological imaging through fluorescence resonance energy transfer (see image). [source]

Signal generation and Raman-resonant imaging by non-degenerate four-wave mixing under tight focusing conditions

Tyler Weeks
Abstract The authors demonstrate Raman-resonant imaging based on the simultaneous generation of several nonlinear frequency mixing processes resulting from a 3-color coherent anti-Stokes Raman scattering (CARS) experiment. The interaction of three coincident short-pulsed laser beams simultaneously generates both 2-color (degenerate) CARS and 3-color (non-degenerate) CARS signals, which are collected and characterized spectroscopically , allowing for resonant, doubly-resonant, and non-resonant contrast mechanisms. Images obtained from both 2-color and 3-color CARS signals are compared and found to provide complementary information. The 3-color CARS microscopy scheme provides a versatile multiplexed modality for biological imaging, which may extend the capabilities of label-free non-linear microscopy, e.g. by probing multiple Raman resonances. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Imaging of cochlear tissue with a grating interferometer and hard X-rays

Claus-Peter Richter
Abstract This article addresses an important current development in medical and biological imaging: the possibility of imaging soft tissue at resolutions in the micron range using hard X-rays. Challenging environments, including the cochlea, require the imaging of soft tissue structure surrounded by bone. We demonstrate that cochlear soft tissue structures can be imaged with hard X-ray phase contrast. Furthermore, we show that only a thin slice of the tissue is required to introduce a large phase shift. It is likely that the phase contrast image of the soft tissue structures is sufficient to image the structures even if surrounded by bone. For the present set of experiments, structures with low-absorption contrast have been visualized using in-line phase contrast imaging and a grating interferometer. The experiments have been performed at the Advanced Photon Source at Argonne National Laboratories, a third generation source of synchrotron radiation. The source provides highly coherent X-ray radiation with high-photon flux (>1012 photons/s) at high-photon energies (5,70 keV). Radiographic and light microscopy images of the gerbil cochlear slice samples were compared. It has been determined that a 20-,m thick tissue slice induces a phase shift between 1/3, and 2/3,. Microsc. Res. Tech., 2009. 2009 Wiley-Liss, Inc. [source]

Matrix vapor deposition/recrystallization and dedicated spray preparation for high-resolution scanning microprobe matrix-assisted laser desorption/ionization imaging mass spectrometry (SMALDI-MS) of tissue and single cells

Werner Bouschen
Matrix preparation techniques such as air spraying or vapor deposition were investigated with respect to lateral migration, integration of analyte into matrix crystals and achievable lateral resolution for the purpose of high-resolution biological imaging. The accessible mass range was found to be beyond 5000 u with sufficient analytical sensitivity. Gas-assisted spraying methods (using oxygen-free gases) provide a good compromise between crystal integration of analyte and analyte migration within the sample. Controlling preparational parameters with this method, however, is difficult. Separation of the preparation procedure into two steps, instead, leads to an improved control of migration and incorporation. The first step is a dry vapor deposition of matrix onto the investigated sample. In a second step, incorporation of analyte into the matrix crystal is enhanced by a controlled recrystallization of matrix in a saturated water atmosphere. With this latter method an effective analytical resolution of 2,m in the x and y direction was achieved for scanning microprobe matrix-assisted laser desorption/ionization imaging mass spectrometry (SMALDI-MS). Cultured A-498 cells of human renal carcinoma were successfully investigated by high-resolution MALDI imaging using the new preparation techniques. Copyright 2010 John Wiley & Sons, Ltd. [source]