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Confocal Microscopes (confocal + microscopes)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Miniaturization of Fluorescence Microscopes Using Fibre Optics

EXPERIMENTAL PHYSIOLOGY, Issue 6 2002
Fritjof Helmchen
In both medical research and diagnostics characterization of biological tissue on the cellular level relies on high-resolution optical microscopy. In most cases, however, tissue is excised for microscopic investigation, in part because conventional microscopes are bulky instruments. Imaging of cells in the intact living organism has been difficult. Over the last decade several groups have developed miniature confocal microscopes that use fibre optics to deliver light to the specimen and to measure either reflected or excited fluorescence light. In addition, two-photon excitation recently has been employed in a small portable ,fibrescope'. A potential clinical application of these microscope probes is their endoscopic use for optical biopsy of inner organs or guidance of conventional biopsy. As a mobile research tool they may permit imaging of neuronal activity in the brain of awake, behaving animals. Here, we review technological approaches to build miniaturized fluorescence microscopes and discuss their potential applications. [source]

Cationic Polyelectrolyte Amplified Bead Array for DNA Detection with Zeptomole Sensitivity and Single Nucleotide Polymorphism Selectivity

ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010
Chun Wang
Abstract A highly sensitive strand specific DNA assay, which consists of a peptide nucleic acid (PNA) probe, a cationic conjugated polymer (PFVP), and self-assembled polystyrene beads in microwell arrays on silicon chip, is reported. PFVP, as an efficient signal amplifier and signal reporter, has been specially designed and synthesized to be compatible with commercial confocal microscopes for sensing on solid substrates. The assay operates on the net increase in negative charge at the PNA surface that occurs upon single-stranded DNA hybridization, which subsequently allows complex formation with the positively charged PFVP to favor energy transfer between the polymer and Cy5-labeled target. With maximized surface contact provided by bead arrays and signal amplification provided by PFVP, this assay allows detection of ,300 copies of Cy5-labeled DNA using a commercial confocal microscope. In addition, the same strategy is also extended for label-free DNA detection with a detection sensitivity of 150 attomole. Excellent discrimination against single nucleotide polymorphism (SNP) is also demonstrated for both Cy5-labeled and label-free target detection. This study indicates that cationic conjugated polymers have great potential to be incorporated into the widely used microarray technology for simplified process with improved detection sensitivity. [source]

Practical limits of resolution in confocal and non-linear microscopy

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2004
Guy Cox
Abstract Calculated and measured resolution figures are presented for confocal microscopes with different pinhole sizes and for nonlinear (2-photon and second harmonic) microscopes. A modest degree of super-resolution is predicted for a confocal microscope but in practice this is not achievable and confocal fluorescence gives little resolution improvement over widefield. However, practical non-linear microscopes do approach their theoretical resolution and therefore show no resolution disadvantage relative to confocal microscopes in spite of the longer excitation wavelength. Microsc. Res. Tech. 63:18,22, 2004. © 2003 Wiley-Liss, Inc. [source]

4411: Immunohistochemical methods to evaluate vitreoretinal scaring

ACTA OPHTHALMOLOGICA, Issue 2010
ML BOCHATON-PIALLAT
Purpose Formation of scarlike epiretinal membranes (ERMs) constitutes potentially the end stage of evolution of proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR) and idiopathic vitreoretinopathy. Among various cellular populations, ERMs contain cells with contractile features typical of myofibroblasts. Myofibroblasts have been described in granulation tissue during wound healing and in practically all fibrocontractive diseases, in which they participate in the generation of isometric tension and in the synthesis of extracellular matrix components; these phenomena are in turn responsible for granulation tissue remodeling and retraction. The main marker of the myofibroblastic phenotype is the expression of alpha-SMA. The transforming growth factor-beta1 and the ED-A splice variant of cellular fibronectin, an extracellular matrix component, are key players of the complex process of myofibroblast differentiation. Methods Proteins were detected by means of immunohistochemical staining on paraffin sections from formol fixed tissues and double immunofluorescence staining on whole tissues. Samples were observed by using classical light and confocal microscopes. Results The presence of alpha-SM actin-positive myofibroblasts was associated with the expression of TGF-beta1, TGF-beta receptor II, and ED-A FN in all types of ERMs studied. Conclusion The results furnish new data on the mechanism of alpha-SM actin stimulation in fibroblasts in a human pathologic setting. [source]