Two-Photon Laser Scanning Confocal Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 847-848
Author(s):  
P.C. Cheng ◽  
S.J. Pan ◽  
A. Shih ◽  
W.S. Liou ◽  
M.S. Park ◽  
...  

Two-photon fluorescence microscopy has become an important research tool in both biological and material sciences. The technique uses long wavelength, typically in the near IR, as the excitation light to obtain shorter wavelength fluorescence (e.g. visible light). Because of the low linear absorption coefficient of most biological and polymeric specimens, this technique allows deeper penetration of the excitation beam, achieving optical sectioning to a depth of 250μm or more into the specimen. As a result of the quadratic dependency of the two-photon induced fluorescence to the excitation intensity, the fluorescent emission and photobleaching are limited to the vicinity of focal spot. This capability of addressing a specimen’s 3D space allows exciting possibilities in biological researches, such as 3D photobleaching recovery experiment.Two-photon confocal fluorescence microscopy is ideal for the study of thick biological and material specimen in 3D. For example, Figure 1 shows a three-dimensional isosurface rendered image of a vascular bundle from a maize stem.

Author(s):  
J. Holy ◽  
G. Schatten

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.


Author(s):  
Hakan Ancin

This paper presents methods for performing detailed quantitative automated three dimensional (3-D) analysis of cell populations in thick tissue sections while preserving the relative 3-D locations of cells. Specifically, the method disambiguates overlapping clusters of cells, and accurately measures the volume, 3-D location, and shape parameters for each cell. Finally, the entire population of cells is analyzed to detect patterns and groupings with respect to various combinations of cell properties. All of the above is accomplished with zero subjective bias.In this method, a laser-scanning confocal light microscope (LSCM) is used to collect optical sections through the entire thickness (100 - 500μm) of fluorescently-labelled tissue slices. The acquired stack of optical slices is first subjected to axial deblurring using the expectation maximization (EM) algorithm. The resulting isotropic 3-D image is segmented using a spatially-adaptive Poisson based image segmentation algorithm with region-dependent smoothing parameters. Extracting the voxels that were labelled as "foreground" into an active voxel data structure results in a large data reduction.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 861
Author(s):  
Jacopo Cardellini ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti

In the past decade(s), fluorescence microscopy and laser scanning confocal microscopy (LSCM) have been widely employed to investigate biological and biomimetic systems for pharmaceutical applications, to determine the localization of drugs in tissues or entire organisms or the extent of their cellular uptake (in vitro). However, the diffraction limit of light, which limits the resolution to hundreds of nanometers, has for long time restricted the extent and quality of information and insight achievable through these techniques. The advent of super-resolution microscopic techniques, recognized with the 2014 Nobel prize in Chemistry, revolutionized the field thanks to the possibility to achieve nanometric resolution, i.e., the typical scale length of chemical and biological phenomena. Since then, fluorescence microscopy-related techniques have acquired renewed interest for the scientific community, both from the perspective of instrument/techniques development and from the perspective of the advanced scientific applications. In this contribution we will review the application of these techniques to the field of drug delivery, discussing how the latest advancements of static and dynamic methodologies have tremendously expanded the experimental opportunities for the characterization of drug delivery systems and for the understanding of their behaviour in biologically relevant environments.


1994 ◽  
Vol 16 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Stephen E. Mahoney ◽  
Stephen W. Paddock ◽  
Louis C. Smith ◽  
Dorothy E. Lewis ◽  
Madeleine Duvic

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1387 ◽  
Author(s):  
M. Galip Icduygu ◽  
Meltem Asilturk ◽  
M. Akif Yalcinkaya ◽  
Youssef K. Hamidi ◽  
M. Cengiz Altan

The three-dimensional nano-morphology of poly(methyl methacrylate; PMMA) microcapsules filled with carbon nanotubes (CNTs) and epoxy resin were investigated by various microscopy methods, including a novel, laser scanning confocal microscopy (LSCM) method. Initially, PMMA microcapsules containing various amounts of CNTs were synthesized by a solvent evaporation method. Scanning electron microscopy analysis showed that pore-free, smooth-surface microcapsules formed with various types of core-shell morphologies. The average size of CNT/epoxy/PMMA microcapsules was shown to decrease from ~52 μm to ~15 μm when mixing speed during synthesis increased from 300 rpm to 1000 rpm. In general, the presence of CNTs resulted in slightly larger microcapsules and higher variations in size. Moreover, three-dimensional scans obtained from confocal microscopy revealed that higher CNT content increased the occurrence and size of CNT aggregates inside the microcapsules. Entrapped submicron air bubbles were also observed inside most microcapsules, particularly within those with higher CNT content.


Biologia ◽  
2009 ◽  
Vol 64 (6) ◽  
Author(s):  
Paulína Gálfiová ◽  
Ivan Varga ◽  
Martin Kopáni ◽  
Peter Michalka ◽  
Jana Michalková ◽  
...  

AbstractThe representation of microcirculation can be approached in several ways. One of the possibilities is to represent the endothelium (endothelial or sinus lining cells) and their basement membrane on the basis of detecting the known components and the expression of the surface antigenes by the methods of immuno-, enzyme- or lectino-histochemical analysis, or by staining or impregnation histological methods. The other possibility is the examination of samples by transmission and scanning electron microscopy. For three-dimensional demonstration corrosion casts techniques or laser scanning confocal microscopy can be used. In this paper we describe the survey of immuno-, enzyme- and lectino-histochemical characteristics of selected components of microcirculation and our own results of its demonstration in human spleen.


1995 ◽  
Vol 406 ◽  
Author(s):  
W. D. Vetter ◽  
M. Dudley ◽  
T.- F. Wong ◽  
J. T. Frderich

AbstractCrystals of silicon carbide, and other polytypic materials often have micropipes associated with screw dislocations of large Burgers vectors running along their axial dimensions. These defects are considered the most deleterious to the performance of SiC semiconductor devices.Optical micrographs of micropipes in silicon carbide crystals are ordinarily faint. To obtain micrographs showing higher contrast and detail, laser scanning confocal microscopy (LSCM) and simple fluorescence microscopy were used on 6H-SiC single crystals after infiltrating them with a low-viscosity epoxy containing a fluorescent dye. “Staining” the micropipes rendered them much more visible both in fluorescence and conventional optical microscopies. Details of their structures and shapes were revealed, and their dimensions were measured accurately, using LSCM and other, less sophisticated, fluorescence microscopies. Other voids present, such as microcracks, were also visualized. Observations by this optical technique were related to information obtained by synchrotron white beam x-ray topography.


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