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Frontiers of Micro-Spectroscopy in Biological Applications

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry".

Deadline for manuscript submissions: closed (30 September 2013) | Viewed by 101853

Special Issue Editor

Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201-0413, USA
Interests: biophysics; biophotonics; optics; optical spectroscopy; dielectric spectroscopy; fluorescence; Förster Resonance Energy Transfer (FRET); protein complex structure; imaging; dynamics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Technological advances seen over the past decades have led to a dramatic reduction in the sample size used in spectroscopic analysis from macroscopic to molecular and supramolecular levels. For instance, development of differing spectral variants of fluorescent proteins that can be fused genetically to proteins of interest allows for imaging of proteins co-localization and oligomerization in living cells, Raman and infrared imaging of cells and cellular organelles discriminates between different macromolecules based on differences in their chemical bonds, while miniaturization of electrodes coupled with the advent of automatic impedance analyzers allows for tag-free detection of macromolecular processes using broad-band dielectric spectroscopy measurement of cells. This special volume is dedicated to the principles of micro-spectroscopy and its applications to the study of single molecules or molecular complexes in solution or inside living cells. Micro-spectroscopy is broadly defined here to include optical (such as fluorescence, Raman, infrared, and second harmonic generation microscopy) and dielectric spectroscopy, in-cell NMR, hyperspectral imaging, etc.

Prof. Dr. Valerica Raicu
Guest Editor

Submission

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Keywords

  • fluorescence micro-spectroscopy
  • raman micro-spectroscopy
  • infrared micro-spectroscopy
  • harmonic-generation microscopy
  • dielectric spectroscopy
  • in-cell NMR
  • hyperspectral molecular imaging

Published Papers (14 papers)

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Research

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489 KiB  
Article
Development and Experimental Testing of an Optical Micro-Spectroscopic Technique Incorporating True Line-Scan Excitation
by Gabriel Biener, Michael R. Stoneman, Gheorghe Acbas, Jessica D. Holz, Marianna Orlova, Liudmila Komarova, Sergei Kuchin and Valerică Raicu
Int. J. Mol. Sci. 2014, 15(1), 261-276; https://doi.org/10.3390/ijms15010261 - 27 Dec 2013
Cited by 50 | Viewed by 7356
Abstract
Multiphoton micro-spectroscopy, employing diffraction optics and electron-multiplying CCD (EMCCD) cameras, is a suitable method for determining protein complex stoichiometry, quaternary structure, and spatial distribution in living cells using Förster resonance energy transfer (FRET) imaging. The method provides highly resolved spectra of molecules or [...] Read more.
Multiphoton micro-spectroscopy, employing diffraction optics and electron-multiplying CCD (EMCCD) cameras, is a suitable method for determining protein complex stoichiometry, quaternary structure, and spatial distribution in living cells using Förster resonance energy transfer (FRET) imaging. The method provides highly resolved spectra of molecules or molecular complexes at each image pixel, and it does so on a timescale shorter than that of molecular diffusion, which scrambles the spectral information. Acquisition of an entire spectrally resolved image, however, is slower than that of broad-bandwidth microscopes because it takes longer times to collect the same number of photons at each emission wavelength as in a broad bandwidth. Here, we demonstrate an optical micro-spectroscopic scheme that employs a laser beam shaped into a line to excite in parallel multiple sample voxels. The method presents dramatically increased sensitivity and/or acquisition speed and, at the same time, has excellent spatial and spectral resolution, similar to point-scan configurations. When applied to FRET imaging using an oligomeric FRET construct expressed in living cells and consisting of a FRET acceptor linked to three donors, the technique based on line-shaped excitation provides higher accuracy compared to the point-scan approach, and it reduces artifacts caused by photobleaching and other undesired photophysical effects. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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1588 KiB  
Article
Detection of Lymph Node Metastases in Human Colorectal Cancer by Using 5-Aminolevulinic Acid-Induced Protoporphyrin IX Fluorescence with Spectral Unmixing
by Kenichi Harada, Yoshinori Harada, Masatomo Beika, Noriaki Koizumi, Koji Inoue, Yasutoshi Murayama, Yoshiaki Kuriu, Masayoshi Nakanishi, Takeo Minamikawa, Yoshihisa Yamaoka, Ping Dai, Akio Yanagisawa, Eigo Otsuji and Tetsuro Takamatsu
Int. J. Mol. Sci. 2013, 14(11), 23140-23152; https://doi.org/10.3390/ijms141123140 - 21 Nov 2013
Cited by 21 | Viewed by 7061
Abstract
Accurate evaluation of metastatic lymph nodes (LNs) is indispensable for adequate treatment of colorectal cancer (CRC) patients. Here, we demonstrate detection of metastases of human CRC in removed fresh LNs using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence. A spectral unmixing method was [...] Read more.
Accurate evaluation of metastatic lymph nodes (LNs) is indispensable for adequate treatment of colorectal cancer (CRC) patients. Here, we demonstrate detection of metastases of human CRC in removed fresh LNs using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence. A spectral unmixing method was employed to reduce the overlap of collagen autofluorescence on PpIX fluorescence. A total of 17 surgery patients with advanced CRC were included in this study. After 5-ALA at a dose of 15 mg/kg of body weight was applied orally 2 h prior to surgery, 87 LNs were subjected to spectral fluorescence imaging and histopathological diagnosis, and statistical analysis was performed. No apparent side effect was observed to be associated with 5-ALA administration. The spectral unmixing fluorescence intensity of PpIX in metastatic LNs was 10.2-fold greater than that in nonmetastaic LNs. The receiver-operating-characteristic (ROC) analysis showed that the area under the curve (AUC) was calculated as 0.95. Our results show the potential of 5-ALA-induced PpIX fluorescence processed by spectral unmixing for detecting metastases in excised fresh LNs from patients with CRC, suggesting that this rapid and feasible method is applicable to gross evaluation of resected LN samples in pathology laboratories. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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812 KiB  
Article
Hydration of AMP and ATP Molecules in Aqueous Solution and Solid Films
by Dzhigangir Faizullin, Nataliya Zakharchenko, Yuriy Zuev, Alexander Puzenko, Evgeniya Levy and Yuri Feldman
Int. J. Mol. Sci. 2013, 14(11), 22876-22890; https://doi.org/10.3390/ijms141122876 - 20 Nov 2013
Cited by 9 | Viewed by 5599
Abstract
Water enables life and plays a critical role in biology. Considered as a versatile and adaptive component of the cell, water engages a wide range of biomolecular interactions. An organism can exist and function only if its self-assembled molecular structures are hydrated. It [...] Read more.
Water enables life and plays a critical role in biology. Considered as a versatile and adaptive component of the cell, water engages a wide range of biomolecular interactions. An organism can exist and function only if its self-assembled molecular structures are hydrated. It was shown recently that switching of AMP/ATP binding to the insulin-independent glucose transporter Human Erythrocyte Glucose Transport Protein (GLUT1) may greatly influence the ratio of bulk and bound water during regulation of glucose uptake by red blood cells. In this paper, we present the results on the hydration properties of AMP/ATP obtained by means of dielectric spectroscopy in aqueous solution and for fully ionized forms in solid amorphous films with the help of gravimetric studies. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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7855 KiB  
Article
Fluorescence Intrinsic Characterization of Excitation-Emission Matrix Using Multi-Dimensional Ensemble Empirical Mode Decomposition
by Chi-Ying Chang, Chia-Chi Chang and Tzu-Chien Hsiao
Int. J. Mol. Sci. 2013, 14(11), 22436-22448; https://doi.org/10.3390/ijms141122436 - 14 Nov 2013
Cited by 13 | Viewed by 5821
Abstract
Excitation-emission matrix (EEM) fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds [...] Read more.
Excitation-emission matrix (EEM) fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds due to overlapping features. Conventional studies use principal component analysis (PCA) for EEM fluorescence analysis, and the relationship between the EEM features extracted by PCA and diseases has been examined. The spectral features of different tissue constituents are not fully separable or clearly defined. Recently, a non-stationary method called multi-dimensional ensemble empirical mode decomposition (MEEMD) was introduced; this method can extract the intrinsic oscillations on multiple spatial scales without loss of information. The aim of this study was to propose a fluorescence spectroscopy system for EEM measurements and to describe a method for extracting the intrinsic characteristics of EEM by MEEMD. The results indicate that, although PCA provides the principal factor for the spectral features associated with chemical compounds, MEEMD can provide additional intrinsic features with more reliable mapping of the chemical compounds. MEEMD has the potential to extract intrinsic fluorescence features and improve the detection of biochemical changes. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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2200 KiB  
Article
Ultrastructural Analysis of Nanogold-Labeled Cell Surface Microvilli in Liquid by Atmospheric Scanning Electron Microscopy and Their Relevance in Cell Adhesion
by Toshiyuki Murai, Mari Sato, Hidetoshi Nishiyama, Mitsuo Suga and Chikara Sato
Int. J. Mol. Sci. 2013, 14(10), 20809-20819; https://doi.org/10.3390/ijms141020809 - 16 Oct 2013
Cited by 16 | Viewed by 7510
Abstract
The adhesion of leukocytes circulating in the blood to vascular endothelium is critical for their trafficking in the vasculature, and CD44 is an important cell surface receptor for rolling adhesion. In this study, we demonstrate the correlative observation of CD44 distribution at the [...] Read more.
The adhesion of leukocytes circulating in the blood to vascular endothelium is critical for their trafficking in the vasculature, and CD44 is an important cell surface receptor for rolling adhesion. In this study, we demonstrate the correlative observation of CD44 distribution at the lymphocyte cell surface in liquid by fluorescence optical microscopy and immuno-electron microscopy using an atmospheric scanning electron microscope (ASEM). The ultrastructure of the cell surface was clearly imaged by ASEM using positively charged Nanogold particles. ASEM analysis demonstrated microvilli projections around the cell surface and the localization of CD44 on the microvilli. Treatment of cells with cytochalasin D resulted in a loss of the microvilli projections and concomitantly abrogated CD44-mediated adhesion to its ligand hyaluronan. These results suggest the functional relevance of microvilli in CD44-mediated rolling adhesion under shear flow. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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834 KiB  
Article
Strengths and Weaknesses of Recently Engineered Red Fluorescent Proteins Evaluated in Live Cells Using Fluorescence Correlation Spectroscopy
by Amanda P. Siegel, Michelle A. Baird, Michael W. Davidson and Richard N. Day
Int. J. Mol. Sci. 2013, 14(10), 20340-20358; https://doi.org/10.3390/ijms141020340 - 14 Oct 2013
Cited by 22 | Viewed by 7645
Abstract
The scientific community is still looking for a bright, stable red fluorescent protein (FP) as functional as the current best derivatives of green fluorescent protein (GFP). The red FPs exploit the reduced background of cells imaged in the red region of the visible [...] Read more.
The scientific community is still looking for a bright, stable red fluorescent protein (FP) as functional as the current best derivatives of green fluorescent protein (GFP). The red FPs exploit the reduced background of cells imaged in the red region of the visible spectrum, but photophysical short comings have limited their use for some spectroscopic approaches. Introduced nearly a decade ago, mCherry remains the most often used red FP for fluorescence correlation spectroscopy (FCS) and other single molecule techniques, despite the advent of many newer red FPs. All red FPs suffer from complex photophysics involving reversible conversions to a dark state (flickering), a property that results in fairly low red FP quantum yields and potential interference with spectroscopic analyses including FCS. The current report describes assays developed to determine the best working conditions for, and to uncover the shortcoming of, four recently engineered red FPs for use in FCS and other diffusion and spectroscopic studies. All five red FPs assayed had potential shortcomings leading to the conclusion that the current best red FP for FCS is still mCherry. The assays developed here aim to enable the rapid evaluation of new red FPs and their smooth adaptation to live cell spectroscopic microscopy and nanoscopy. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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956 KiB  
Article
Microscale Diffusion Measurements and Simulation of a Scaffold with a Permeable Strut
by Seung Youl Lee, Byung Ryong Lee, Jongwan Lee, Seongjun Kim, Jung Kyung Kim, Young Hun Jeong and Songwan Jin
Int. J. Mol. Sci. 2013, 14(10), 20157-20170; https://doi.org/10.3390/ijms141020157 - 10 Oct 2013
Cited by 8 | Viewed by 6698
Abstract
Electrospun nanofibrous structures provide good performance to scaffolds in tissue engineering. We measured the local diffusion coefficients of 3-kDa FITC-dextran in line patterns of electrospun nanofibrous structures fabricated by the direct-write electrospinning (DWES) technique using the fluorescence recovery after photobleaching (FRAP) method. No [...] Read more.
Electrospun nanofibrous structures provide good performance to scaffolds in tissue engineering. We measured the local diffusion coefficients of 3-kDa FITC-dextran in line patterns of electrospun nanofibrous structures fabricated by the direct-write electrospinning (DWES) technique using the fluorescence recovery after photobleaching (FRAP) method. No significant differences were detected between DWES line patterns fabricated with polymer supplied at flow rates of 0.1 and 0.5 mL/h. The oxygen diffusion coefficients of samples were estimated to be ~92%–94% of the oxygen diffusion coefficient in water based on the measured diffusion coefficient of 3-kDa FITC-dextran. We also simulated cell growth and distribution within spatially patterned scaffolds with struts consisting of either oxygen-permeable or non-permeable material. The permeable strut scaffolds exhibited enhanced cell growth. Saturated depths at which cells could grow to confluence were 15% deeper for the permeable strut scaffolds than for the non-permeable strut scaffold. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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1641 KiB  
Article
Spectroscopic Studies of Model Photo-Receptors: Validation of a Nanosecond Time-Resolved Micro-Spectrophotometer Design Using Photoactive Yellow Protein and α-Phycoerythrocyanin
by Namrta Purwar, Jason Tenboer, Shailesh Tripathi and Marius Schmidt
Int. J. Mol. Sci. 2013, 14(9), 18881-18898; https://doi.org/10.3390/ijms140918881 - 13 Sep 2013
Cited by 8 | Viewed by 6920
Abstract
Time-resolved spectroscopic experiments have been performed with protein in solution and in crystalline form using a newly designed microspectrophotometer. The time-resolution of these experiments can be as good as two nanoseconds (ns), which is the minimal response time of the image intensifier used. [...] Read more.
Time-resolved spectroscopic experiments have been performed with protein in solution and in crystalline form using a newly designed microspectrophotometer. The time-resolution of these experiments can be as good as two nanoseconds (ns), which is the minimal response time of the image intensifier used. With the current setup, the effective time-resolution is about seven ns, determined mainly by the pulse duration of the nanosecond laser. The amount of protein required is small, on the order of 100 nanograms. Bleaching, which is an undesirable effect common to photoreceptor proteins, is minimized by using a millisecond shutter to avoid extensive exposure to the probing light. We investigate two model photoreceptors, photoactive yellow protein (PYP), and α-phycoerythrocyanin (α-PEC), on different time scales and at different temperatures. Relaxation times obtained from kinetic time-series of difference absorption spectra collected from PYP are consistent with previous results. The comparison with these results validates the capability of this spectrophotometer to deliver high quality time-resolved absorption spectra. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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754 KiB  
Article
Differential Polarization Nonlinear Optical Microscopy with Adaptive Optics Controlled Multiplexed Beams
by Masood Samim, Daaf Sandkuijl, Ian Tretyakov, Richard Cisek and Virginijus Barzda
Int. J. Mol. Sci. 2013, 14(9), 18520-18534; https://doi.org/10.3390/ijms140918520 - 09 Sep 2013
Cited by 14 | Viewed by 8104
Abstract
Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved [...] Read more.
Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red), which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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1301 KiB  
Article
Using Synchrotron Radiation-Based Infrared Microspectroscopy to Reveal Microchemical Structure Characterization: Frost Damaged Wheat vs. Normal Wheat
by Hangshu Xin, Xuewei Zhang and Peiqiang Yu
Int. J. Mol. Sci. 2013, 14(8), 16706-16718; https://doi.org/10.3390/ijms140816706 - 14 Aug 2013
Cited by 21 | Viewed by 6559
Abstract
This study was conducted to compare: (1) protein chemical characteristics, including the amide I and II region, as well as protein secondary structure; and (2) carbohydrate internal structure and functional groups spectral intensities between the frost damaged wheat and normal wheat using synchrotron [...] Read more.
This study was conducted to compare: (1) protein chemical characteristics, including the amide I and II region, as well as protein secondary structure; and (2) carbohydrate internal structure and functional groups spectral intensities between the frost damaged wheat and normal wheat using synchrotron radiation-based Fourier transform infrared microspectroscopy (SR-FTIRM). Fingerprint regions of specific interest in our study involved protein and carbohydrate functional group band assignments, including protein amide I and II (ca. 1774–1475 cm−1), structural carbohydrates (SCHO, ca. 1498–1176 cm−1), cellulosic compounds (CELC, ca. 1295–1176 cm−1), total carbohydrates (CHO, ca. 1191–906 cm−1) and non-structural carbohydrates (NSCHO, ca. 954–809 cm−1). The results showed that frost did cause variations in spectral profiles in wheat grains. Compared with healthy wheat grains, frost damaged wheat had significantly lower (p < 0.05) spectral intensities in height and area ratios of amide I to II and almost all the spectral parameters of carbohydrate-related functional groups, including SCHO, CHO and NSCHO. Furthermore, the height ratio of protein amide I to the third peak of CHO and the area ratios of protein amide (amide I + II) to carbohydrate compounds (CHO and SCHO) were also changed (p < 0.05) in damaged wheat grains. It was concluded that the SR-FTIR microspectroscopic technique was able to examine inherent molecular structure features at an ultra-spatial resolution (10 × 10 μm) between different wheat grains samples. The structural characterization of wheat was influenced by climate conditions, such as frost damage, and these structural variations might be a major reason for the decreases in nutritive values, nutrients availability and milling and baking quality in wheat grains. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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1179 KiB  
Article
Correlation of Dual Colour Single Particle Trajectories for Improved Detection and Analysis of Interactions in Living Cells
by Hendrik Deschout, Thomas Martens, Dries Vercauteren, Katrien Remaut, Jo Demeester, Stefaan C. De Smedt, Kristiaan Neyts and Kevin Braeckmans
Int. J. Mol. Sci. 2013, 14(8), 16485-16514; https://doi.org/10.3390/ijms140816485 - 08 Aug 2013
Cited by 13 | Viewed by 7108
Abstract
Interactions between objects inside living cells are often investigated by looking for colocalization between fluorescence microscopy images that are recorded in separate colours corresponding to the fluorescent label of each object. The fundamental limitation of this approach in the case of dynamic objects [...] Read more.
Interactions between objects inside living cells are often investigated by looking for colocalization between fluorescence microscopy images that are recorded in separate colours corresponding to the fluorescent label of each object. The fundamental limitation of this approach in the case of dynamic objects is that coincidental colocalization cannot be distinguished from true interaction. Instead, correlation between motion trajectories obtained by dual colour single particle tracking provides a much stronger indication of interaction. However, frequently occurring phenomena in living cells, such as immobile phases or transient interactions, can limit the correlation to small parts of the trajectories. The method presented here, developed for the detection of interaction, is based on the correlation inside a window that is scanned along the trajectories, covering different subsets of the positions. This scanning window method was validated by simulations and, as an experimental proof of concept, it was applied to the investigation of the intracellular trafficking of polymeric gene complexes by endosomes in living retinal pigment epithelium cells, which is of interest to ocular gene therapy. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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Review

Jump to: Research

1616 KiB  
Review
Opportunities for Live Cell FT-Infrared Imaging: Macromolecule Identification with 2D and 3D Localization
by Eric C. Mattson, Ebrahim Aboualizadeh, Marie E. Barabas, Cheryl L. Stucky and Carol J. Hirschmugl
Int. J. Mol. Sci. 2013, 14(11), 22753-22781; https://doi.org/10.3390/ijms141122753 - 19 Nov 2013
Cited by 26 | Viewed by 7854
Abstract
Infrared (IR) spectromicroscopy, or chemical imaging, is an evolving technique that is poised to make significant contributions in the fields of biology and medicine. Recent developments in sources, detectors, measurement techniques and speciman holders have now made diffraction-limited Fourier transform infrared (FTIR) imaging [...] Read more.
Infrared (IR) spectromicroscopy, or chemical imaging, is an evolving technique that is poised to make significant contributions in the fields of biology and medicine. Recent developments in sources, detectors, measurement techniques and speciman holders have now made diffraction-limited Fourier transform infrared (FTIR) imaging of cellular chemistry in living cells a reality. The availability of bright, broadband IR sources and large area, pixelated detectors facilitate live cell imaging, which requires rapid measurements using non-destructive probes. In this work, we review advances in the field of FTIR spectromicroscopy that have contributed to live-cell two and three-dimensional IR imaging, and discuss several key examples that highlight the utility of this technique for studying the structure and chemistry of living cells. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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2838 KiB  
Review
The Characterisation of Pluripotent and Multipotent Stem Cells Using Fourier Transform Infrared Microspectroscopy
by Julie Cao, Elizabeth S. Ng, Donald McNaughton, Edouard G. Stanley, Andrew G. Elefanty, Mark J. Tobin and Philip Heraud
Int. J. Mol. Sci. 2013, 14(9), 17453-17476; https://doi.org/10.3390/ijms140917453 - 26 Aug 2013
Cited by 24 | Viewed by 7035
Abstract
Fourier transform infrared (FTIR) microspectroscopy shows potential as a benign, objective and rapid tool to screen pluripotent and multipotent stem cells for clinical use. It offers a new experimental approach that provides a holistic measurement of macromolecular composition such that a signature representing [...] Read more.
Fourier transform infrared (FTIR) microspectroscopy shows potential as a benign, objective and rapid tool to screen pluripotent and multipotent stem cells for clinical use. It offers a new experimental approach that provides a holistic measurement of macromolecular composition such that a signature representing the internal cellular phenotype is obtained. The use of this technique therefore contributes information that is complementary to that acquired by conventional genetic and immunohistochemical methods. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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558 KiB  
Review
Neuron Biomechanics Probed by Atomic Force Microscopy
by Elise Spedden and Cristian Staii
Int. J. Mol. Sci. 2013, 14(8), 16124-16140; https://doi.org/10.3390/ijms140816124 - 05 Aug 2013
Cited by 63 | Viewed by 9897
Abstract
Mechanical interactions play a key role in many processes associated with neuronal growth and development. Over the last few years there has been significant progress in our understanding of the role played by the substrate stiffness in neuronal growth, of the cell-substrate adhesion [...] Read more.
Mechanical interactions play a key role in many processes associated with neuronal growth and development. Over the last few years there has been significant progress in our understanding of the role played by the substrate stiffness in neuronal growth, of the cell-substrate adhesion forces, of the generation of traction forces during axonal elongation, and of the relationships between the neuron soma elastic properties and its health. The particular capabilities of the Atomic Force Microscope (AFM), such as high spatial resolution, high degree of control over the magnitude and orientation of the applied forces, minimal sample damage, and the ability to image and interact with cells in physiologically relevant conditions make this technique particularly suitable for measuring mechanical properties of living neuronal cells. This article reviews recent advances on using the AFM for studying neuronal biomechanics, provides an overview about the state-of-the-art measurements, and suggests directions for future applications. Full article
(This article belongs to the Special Issue Frontiers of Micro-Spectroscopy in Biological Applications)
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