Characterization of absorption and scattering properties for various yeast strains by time-resolved spectroscopy

Beauvoit, Bertrand; Liu, H.; Kang, Kyung A.; Kaplan, Peter D.; Miwa, Makoto; Chance, Britton

doi:10.1007/bf02796508

Cited by 58 publications

(37 citation statements)

References 21 publications

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“…3(b,d). It can be seen that both algorithms present similar refractive-index values of the inner cell contents, between 1.34−1.39, coinciding with the expected values for yeast cells [22]. The appearance of vacuoles, containing mostly water, is noticeable.…”

Section: Resultssupporting

confidence: 57%

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Tomographic phase microscopy using optical tweezers

et al. 2015

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We review our technique for tomographic phase microscopy with optical tweezers [1]. This tomographic phase microscopy approach enables full 3-D refractive-index reconstruction. Tomographic phase microscopy measures quantitatively the 3-D distribution of refractive-index in biological cells. We integrated our external interferometric module with holographic optical tweezers for obtaining quantitative phase maps of biological samples from a wide range of angles. The close-tocommon-path, off-axis interferometric system enables a full-rotation tomographic acquisition of a single cell using holographic optical tweezers for trapping and manipulating with a desired array of traps, while acquiring phase information of a single cell from all different angles and maintaining the native surrounding medium. We experimentally demonstrated two reconstruction algorithms: the filtered back-projection method and the Fourier diffraction method for 3-D refractive index imaging of yeast cells.

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Section: Resultssupporting

confidence: 57%

“…We performed TPM of yeast cells (Saccharomyces Cerevisiae, longitudinal diameter range of 5-10 µm), which are eukaryotic organisms that are helpful in noninvasive biological studies [22]. We created two traps near the edges of cells along the y axis, as illustrated in Fig.…”

Section: Datamentioning

confidence: 99%

Tomographic phase microscopy using optical tweezers

et al. 2015

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“…Spectroscopic measurements of light scattering by red blood cells by Steinke and Shepherd, 14 yeast cells by Beauvoit, Chance, and colleagues, 15 and tissue phantoms consisting of suspensions of polystyrene spheres of different size by Mourant, Bigio, and colleagues 16 demonstrated that Mie theory can be used to describe scattering characteristics of those micrometer sized objects.…”

Section: Light Scattering From Cells and Subcellular Structuresmentioning

confidence: 99%

Spectroscopy of Scattered Light for the Characterization of Micro and Nanoscale Objects in Biology and Medicine

et al. 2014

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The biomedical uses for the spectroscopy of scattered light by micro and nanoscale objects can broadly be classified into two areas. The first, often called light scattering spectroscopy (LSS), deals with light scattered by dielectric particles, such as cellular and sub-cellular organelles, and is employed to measure their size or other physical characteristics. Examples include the use of LSS to measure the size distributions of nuclei or mitochondria. The native contrast that is achieved with LSS can serve as a non-invasive diagnostic and scientific tool. The other area for the use of the spectroscopy of scattered light in biology and medicine involves using conducting metal nanoparticles to obtain either contrast or electric field enhancement through the effect of the surface plasmon resonance (SPR). Gold and silver metal nanoparticles are non-toxic, they do not photobleach, are relatively inexpensive, are wavelength-tunable, and can be labeled with antibodies. This makes them very promising candidates for spectrally encoded molecular imaging. Metal nanoparticles can also serve as electric field enhancers of Raman signals. Surface enhanced Raman spectroscopy (SERS) is a powerful method for detecting and identifying molecules down to single molecule concentrations. In this review, we will concentrate on the common physical principles, which allow one to understand these apparently different areas using similar physical and mathematical approaches. We will also describe the major advancements in each of these areas, as well as some of the exciting recent developments.Index headings: Light scattering; Spectroscopy; Nanoparticle; Surface plasmon; Surface enhanced Raman; SERS. INTRODUCTIONT he spectroscopy of scattered light has played an increasingly important role in biology and medicine because it can provide information about subcellular and extracellular biological structures using native contrast, as well as information about nanoparticles that are employed as the exogenous imaging markers or vehicles for the delivery of therapeutic agents. Light scattering by these microscopic objects is governed by the very basic principles of electromagnetic wave propagation and interaction with matter developed many decades ago. The impressive advances in biomedical instrumentation that have recently been achieved are examples of the successful applications of these fundamental principles. An analogy can be made between the development of biomedical light scattering and the development of other medical imaging modalities, for example the discovery of the very basic physics of X-rays led to the development of computed tomography decades later, while the initial understanding of another basic physical effect, nuclear magnetic resonance, eventually led to magnetic resonance imaging. Thus it can be argued that the field of biomedical optics is primarily concerned with the technological development of new medical applications of electromagnetic wave interactions, described by Maxwell's equations, with exogenous and endogenous...

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“…10 Previous work has demonstrated that scattering of light by human tissue occurs from both the cells themselves and organelles within the cells, such as the mitochondria and nuclei. 11,12 However, by far the predominate cell type of blood is the erythrocyte or red blood cell (approximately 5ϫ10 6 /L versus 4ϫ10 3 /L for the white blood cell). Because mature erythrocytes contain no nucleus or organelles, it can be hypothesized that the red cell volume is the major source of scattering.…”

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confidence: 99%

Index Matching to Improve Optical Coherence Tomography Imaging Through Blood

et al. 2001

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Background-Most myocardial infarctions are caused by the rupture of small rather than large plaques in the arteries of the heart that are beyond the detection limit of current technologies. Methods and Results-Recently, optical coherence tomography (OCT) has demonstrated considerable potential as a method for high-resolution assessment of vulnerable plaque. However, intravascular OCT imaging is complicated by the need to remove blood from the imaging field because blood results in substantial signal attenuation. This work examines index matching as a method for increasing penetration. Index matching is based on the hypothesis that the predominant source of scattering in blood is the difference in refractive index between the cytoplasm of erythrocytes and serum. By increasing the refractive index of serum to a value near that of the cytoplasm, or index matching, scattering can be substantially reduced. The concept was tested with a system that pumped blood in vitro through transparent tubing. The test compounds, dextran and intravenous contrast agent, both led to significant improvements in penetration (69Ϯ12% and 45Ϯ4%). No significant effect was seen with the saline control. For dextran, the effect could not be attributed to reductions of red cell number or volume because changes in these parameters were not different from the control. In the case of intravenous contrast, a small but significant relative reduction in red cell volume was seen. Conclusions-This study demonstrates the feasibility of index matching for improving OCT imaging through blood.Future studies are required to identify compounds for effective index matching in vivo. Key Words: tomography Ⅲ plaque Ⅲ myocardial infarction Ⅲ blood Ⅲ imaging M yocardial infarction, commonly known as heart attack, is the leading cause of death in the industrialized world. 1 Most myocardial infarctions result from the rupture of small, thin-walled plaques in the coronary arteries. When these plaques rupture, they release lipid into the blood, a clot forms, and the vessel occludes. 2,3 Most of these plaques are below the detection limit of currently available imaging technologies. 4 Therefore, a true clinical need exists for an imaging technology capable of identifying these plaques before rupture.A recently developed, high-resolution imaging technology, optical coherence technology (OCT), has demonstrated considerable potential as a method for imaging vulnerable plaque. [5][6][7][8] OCT is analogous to ultrasound, measuring the intensity of back-reflected infrared light rather than sound. 9 Initial in vitro OCT imaging of cardiovascular tissue was conducted with postmortem human aorta. 5 In these studies, OCT was shown to identify structural features such as lipid collections, thin intimal caps, and fissures characteristic of plaque vulnerablity. OCT has also been directly compared with high-frequency intravascular ultrasound, the current clinical technology with the highest resolution. 6,7 The superior resolution of OCT has been confirmed both quantitatively and...

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Characterization of absorption and scattering properties for various yeast strains by time-resolved spectroscopy

Cited by 58 publications

References 21 publications

Tomographic phase microscopy using optical tweezers

Tomographic phase microscopy using optical tweezers

Spectroscopy of Scattered Light for the Characterization of Micro and Nanoscale Objects in Biology and Medicine

Index Matching to Improve Optical Coherence Tomography Imaging Through Blood

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