Label-free optical imaging of live cells

Chan, K. L. Andrew; Fale, Pedro

doi:10.1016/b978-0-85709-662-3.00008-7

Cited by 4 publications

(1 citation statement)

References 109 publications

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“…The amide I region (∼1640 cm −1 ) was excluded in the PCA, as the water peak at this region exceeded 1, which indicates that the detector will not operate in linear response at this band (Figure S4). 23,39 ■ ASSOCIATED CONTENT * sı Supporting Information…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Identifying the Responses from the Estrogen Receptor-Expressed MCF7 Cells Treated in Anticancer Drugs of Different Modes of Action Using Live-Cell FTIR Spectroscopy

2020

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Recently, we have shown that changes in Fourier transform infrared (FTIR) spectra of living MDA-MB-231 cells (a triple negative cell line) upon exposure to anticancer drugs reflect the changes in the cellular compositions which are correlated to the modes of action of drugs. In the present study, MCF7 cells (an estrogen receptor expressing breast cancer cell line) were exposed to three anticancer drugs belonging to two well-characterized anticancer classes: selective estrogen receptor modulators (SERMs) and DNA-intercalating agent. First, we evaluated if the changes in the spectrum of cells are according to the modes of action of drugs and the characteristics of the MCF7 cell line in the same way as the MDA-MB-231 cell. Living MCF7 cells were treated in the three drugs at half maximal inhibitory concentration (IC50), and the difference spectra were analyzed using principal component analysis (PCA). The results demonstrated clear separation between tamoxifen/toremifene (SERM)-treated cells from the doxorubicin (DNA-intercalator)-treated and untreated cells (control). Tamoxifen and toremifene induced similar spectral changes in the cellular compositions of MCF7 cells and lead to the clustering of these two drugs in the same quadrant of the principal component 1 (PC1) versus PC2 score plots. The separation is mostly attributed to their similar modes of actions. However, doxorubicin-treated MCF7 cells highlighted spectral changes that mainly occur in bands at 1085 and 1200–1240 cm–1, which could be associated with the DNA-intercalation effects of the drug. Second, the pairwise PCA at various individual time points was employed to investigate whether the spectral changes of MCF7 and MDA-MB-231 cells in response to the IC50 of tamoxifen/toremifene and doxorubicin are dependent on the characteristics of the cell lines. The estrogen-expressing MCF7 cells demonstrated significant differences in response to the SERMs in comparison to the triple negative MDA-MB-231 cells, suggesting that different modes of action have taken place in the two tested cell lines. In contrast, the doxorubicin-treated MDA-MB-231 and MCF7 cells show similar changes in 1150–950 cm–1, which indicates that the DNA intercalation effect of doxorubicin is found in both cell lines. The results have demonstrated that live-cell FTIR analysis is sensitive to the different modes of action from the same drugs on cells with different characteristics.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Identifying the Responses from the Estrogen Receptor-Expressed MCF7 Cells Treated in Anticancer Drugs of Different Modes of Action Using Live-Cell FTIR Spectroscopy

2020

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An Introduction to Infra‐red andRaman Spectroscopies for Pharmaceutical and Biomedical Studies

Chan

2019

Biomolecular and Bioanalytical Techniques

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Subcellular mapping of living cells via synchrotron microFTIR and ZnS hemispheres

et al. 2018

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FTIR imaging is a label-free, non-destructive method valuably exploited in the study of the biological process in living cells. However, the long wavelength/low spatial resolution and the strong absorbance of water are still key constrains in the application of IR microscopy ex vivo. In this work, a new retrofit approach based on the use of ZnS hemispheres is introduced to significantly improve the spatial resolution on live cell FTIR imaging. By means of two high refractive index domes sandwiching the sample, a lateral resolution close to 2.2 μm at 6 μm wavelength has been achieved, i.e. below the theoretical diffraction limit in air and more than twice the improvement (to ~λ/2.7) from our previous attempt using CaF2 lenses. The ZnS domes also allowed an extended spectral range to 950 cm−1, in contrast to the cut-off at 1050 cm−1 using CaF2. In combination with synchrotron radiation source, microFTIR provides an improved signal-to-noise ratio through the circa 12 μm thin layer of medium, thus allowing detailed distribution of lipids, protein and nucleic acid in the surround of the nucleus of single living cells. Endoplasmic reticula were clearly shown based on the lipid ν(CH) and ν(C=O) bands, while the DNA was imaged based on the ν(PO2−) band highlighting the nucleus region. This work has also included a demonstration of drug (doxorubicin) in cell measurement to highlight the potential of this approach. Graphical abstract Electronic supplementary materialThe online version of this article (10.1007/s00216-018-1245-x) contains supplementary material, which is available to authorized users.

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Label-free optical imaging of live cells

Cited by 4 publications

References 109 publications

Identifying the Responses from the Estrogen Receptor-Expressed MCF7 Cells Treated in Anticancer Drugs of Different Modes of Action Using Live-Cell FTIR Spectroscopy

Identifying the Responses from the Estrogen Receptor-Expressed MCF7 Cells Treated in Anticancer Drugs of Different Modes of Action Using Live-Cell FTIR Spectroscopy

An Introduction to Infra‐red andRaman Spectroscopies for Pharmaceutical and Biomedical Studies

Subcellular mapping of living cells via synchrotron microFTIR and ZnS hemispheres

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