Protein hydration in living cells probed by Fourier transform infrared (FT-IR) spectroscopic imaging

The Analyst ◽  
2017 ◽  
Vol 142 (13) ◽  
pp. 2475-2483 ◽  
Author(s):  
H. Shinzawa ◽  
B. Turner ◽  
J. Mizukado ◽  
S. G. Kazarian
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Spectroscopic Imaging ◽  
Fourier Transform Infrared ◽  
Living Cells ◽  
Protein Hydration ◽  
Ft Ir ◽  
Ir Spectroscopic

FT-IR spectra of a HEK cell were analyzed with 2D disrelation mapping to reveal molecular states of water and protein hydration.

scholarly journals Transmission Fourier Transform Infrared Spectroscopic Imaging, Mapping, and Synchrotron Scanning Microscopy with Zinc Sulfide Hemispheres on Living Mammalian Cells at Sub-Cellular Resolution

2020 ◽  
Vol 74 (5) ◽  
pp. 544-552 ◽  
Author(s):  
Ka Lung Andrew Chan ◽  
Ali Altharawi ◽  
Pedro Fale ◽  
Cai Li Song ◽  
Sergei G. Kazarian ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Synchrotron Radiation ◽  
Zinc Sulfide ◽  
Spatial Resolution ◽  
Single Point ◽  
Spectroscopic Imaging ◽  
Fourier Transform Infrared ◽  
Living Cells ◽  
Imaging Systems ◽  
Ft Ir

Fourier transform infrared (FT-IR) spectroscopic imaging and microscopy of single living cells are established label-free technique for the study of cell biology. The constant driver to improve the spatial resolution of the technique is due to the diffraction limit given by infrared (IR) wavelength making subcellular study challenging. Recently, we have reported, with the use of a prototype zinc sulfide (ZnS) transmission cell made of two hemispheres, that the spatial resolution is improved by the factor of the refractive index of ZnS, achieving a λ/2.7 spatial resolution using the synchrotron–IR microscopy with a 36× objective with numerical aperture of 0.5. To refine and to demonstrate that the ZnS hemisphere transmission device can be translated to standard bench-top FT-IR imaging systems, we have, in this work, modified the device to achieve a more precise path length, which has improved the spectral quality of the living cells, and showed for the first time that the device can be applied to study live cells with three different bench-top FT-IR imaging systems. We applied focal plane array (FPA) imaging, linear array, and a synchrotron radiation single-point scanning method and demonstrated that in all cases, subcellular details of individual living cells can be obtained. Results have shown that imaging with the FPA detector can measure the largest area in a given time, while measurements from the scanning methods produced a smoother image. Synchrotron radiation single-point mapping produced the best quality image and has the flexibility to introduce over sampling to produce images of cells with great details, but it is time consuming in scanning mode. In summary, this work has demonstrated that the ZnS hemispheres can be applied in all three spectroscopic approaches to improve the spatial resolution without any modification to the existing microscopes.

Generalized Implementation of Rapid-Scan Fourier Transform Infrared Spectroscopic Imaging

2002 ◽  
Vol 56 (8) ◽  
pp. 965-969 ◽  
Author(s):  
Scott W. Huffman ◽  
Rohit Bhargava ◽  
Ira W. Levin
Keyword(s):  
Fourier Transform ◽  
Data Acquisition ◽  
Spectroscopic Imaging ◽  
Fourier Transform Infrared ◽  
Imaging Data ◽  
Rapid Scan ◽  
Continuous Scanning ◽  
Ft Ir ◽  
Ir Instrumentation ◽  
Ir Spectroscopic

We describe a novel, generalized data acquisition sequence to allow rapid-scan Fourier transform infrared (FT-IR) spectroscopic imaging using focal plane array (FPA) detectors. This technique derives its applicability from the reproducible performance of modern FT-IR instrumentation and the availability of FPAs with simultaneous, full array acquisition, or snapshot electronics. Instead of sampling the entire interferogram in one mirror sweep over a predetermined retardation, as in traditional continuous-scanning techniques, the modulated light from the interferometer is recorded over several mirror sweeps. The FPA detector is synchronized for data acquisition after a specified delay with respect to the initiation of the mirror motion to provide a highly under-sampled interferogram. By incorporating appropriate delays in subsequent interferometer mirror scans, the entire interferogram is sampled and reconstructed. The signal-to-noise ratios (SNR) of the resulting interferograms are analyzed and are compared with step-scan spectroscopic imaging data.

scholarly journals Application of Fourier Transform Infrared Spectroscopy and Chemometrics for Differentiation of Salmonella enterica Serovar Enteritidis Phage Types

2010 ◽  
Vol 76 (11) ◽  
pp. 3538-3544 ◽  
Author(s):  
Ornella Preisner ◽  
Raquel Guiomar ◽  
Jorge Machado ◽  
Jos� Cardoso Menezes ◽  
Jo�o Almeida Lopes
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Salmonella Enterica ◽  
Intact Cell ◽  
Phage Type ◽  
Fourier Transform Infrared ◽  
Intact Cells ◽  
Phage Types ◽  
Ft Ir ◽  
Ir Analysis

ABSTRACT Fourier transform infrared (FT-IR) spectroscopy and chemometric techniques were used to discriminate five closely related Salmonella enterica serotype Enteritidis phage types, phage type 1 (PT1), PT1b, PT4b, PT6, and PT6a. Intact cells and outer membrane protein (OMP) extracts from bacterial cell membranes were subjected to FT-IR analysis in transmittance mode. Spectra were collected over a wavenumber range from 4,000 to 600 cm−1. Partial least-squares discriminant analysis (PLS-DA) was used to develop calibration models based on preprocessed FT-IR spectra. The analysis based on OMP extracts provided greater separation between the Salmonella Enteritidis PT1-PT1b, PT4b, and PT6-PT6a groups than the intact cell analysis. When these three phage type groups were considered, the method based on OMP extract FT-IR spectra was 100% accurate. Moreover, complementary local models that considered only the PT1-PT1b and PT6-PT6a groups were developed, and the level of discrimination increased. PT1 and PT1b isolates were differentiated successfully with the local model using the entire OMP extract spectrum (98.3% correct predictions), whereas the accuracy of discrimination between PT6 and PT6a isolates was 86.0%. Isolates belonging to different phage types (PT19, PT20, and PT21) were used with the model to test its robustness. For the first time it was demonstrated that FT-IR analysis of OMP extracts can be used for construction of robust models that allow fast and accurate discrimination of different Salmonella Enteritidis phage types.

Time-Resolved Fourier Transform Infrared Spectroscopic Imaging

2003 ◽  
Vol 57 (4) ◽  
pp. 357-366 ◽  
Author(s):  
Rohit Bhargava ◽  
Ira W. Levin
Keyword(s):  
Fourier Transform ◽  
Imaging Modality ◽  
Spectroscopic Imaging ◽  
Fourier Transform Infrared ◽  
Dynamic Processes ◽  
Time Resolved ◽  
Ir Imaging ◽  
Infrared Spectroscopic ◽  
Infrared Spectroscopic Imaging ◽  
Ft Ir

Fourier transform infrared (FT-IR) imaging allows simultaneous spectral characterization of large spatial areas due to its multichannel detection advantage. The acquisition of large amounts of data in the multichannel configuration results, however, in a poor temporal resolution of sequentially acquired data sets, which limits the examination of dynamic processes to processes that have characteristic time scales of the order of minutes. Here, we introduce the concept and instrumental details of a time-resolved infrared spectroscopic imaging modality that permits the examination of repetitive dynamic processes whose half-lives are of the order of milliseconds. As an illustration of this implementation of step-scan FT-IR imaging, we examine the molecular responses to external electric-field perturbations of a microscopically heterogeneous polymer–liquid crystal composite. Analysis of the spectroscopic data using conventional univariate and generalized two-dimensional (2D) correlation methods emphasizes an additional capability for accessing of simultaneous spatial and temporal chemical measurements of molecular dynamic processes.

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