Raman Microscopy for the Chemometric Analysis of Tumor Cells

Taleb, Ahcene; Diamond, James J.; McGarvey, John J.; Beattie, J. Renwick; Toland, Carla; Hamilton, Peter

doi:10.1021/jp061981q

Cited by 97 publications

(88 citation statements)

References 26 publications

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“…Normal Raman signals from cells and their infrared (FTIR) absorbance patterns have been previously used to differentiate between cancer and normal cells (6)(7)(8)(9). SERS has been used as an alternative immunohistochemistry (IHC) tool (10,11) for the detection of biomarkers in biological fluids or in vivo (12), and for cancer detection from blood (13).…”

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confidence: 99%

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Pallaoro

Braun

Moskovits

2011

Proc. Natl. Acad. Sci. U.S.A.

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A multiplexed, ratiometric method is described that can confidently distinguish between cancerous and noncancerous epithelial prostate cells in vitro. The technique is based on bright surfaceenhanced resonance Raman scattering (SERRS) biotags (SBTs) infused with unique Raman reporter molecules, and carrying cellspecific peptides. Two sets of SBTs were used. One targets the neuropilin-1 (NRP-1) receptors of cancer cells through the RPARPAR peptide. The other functions as a positive control (PC) and binds to both noncancerous and cancer cells through the HIV-derived TAT peptide. Point-by-point 2D Raman maps of the spatial distribution of the two tags were constructed with subcellular resolution from cells simultaneously incubated with the two sets of SBTs. Averaging the SERRS signal over a given cell yielded an NRP/PC ratio from which a robust quantitative measure of the overexpression of the NRP-1 by the cancer cell line was extracted. The use of a local, on-cell reference produces quantitative, statistically robust measures of overexpression independent of such sources of uncertainty as variations in the location of the focal plane, the local cell concentration, and turbidity.surface-enhanced Raman spectroscopy biomarker | cancer cell identification | multiplexing | silver nanoparticles E arly and rapid identification of malignant cells [ideally freeflowing in biological fluids such as urine (1) or blood (2-4)] is a central goal in cancer research. Accordingly, seeking improvements in sensitivity and accuracy of detection and quantification through, for example, the development of cell-specific diagnostic tools and biomarkers is an active enterprise. Although it is known that such cells are present in body fluids, concentrating them to levels appropriate for confident identification and quantification is still a serious challenge, despite significant advances that have been made by, for example, using microfluidics (5). Once collected, the cells must be identified as either cancerous or noncancerous within tolerable confidence limits, which may be improved by, for example, using several nonredundant biomarkers. Numerous promising identification methods have been reported using antibodies. In this article, we report a technique based on surface-enhanced Raman spectroscopy (SERS) and biotags that produce bright surface-enhanced resonance Raman scattering (SERRS) signals, comparable to or exceeding the intensities of fluorescent tags. The SERRS biotags (SBTs) used in this study exploit peptides as recognition moieties. We show that using SBTs ratiometrically can provide highly statistically significant, quantitative measures of neuropilin-1 (NRP-1) overexpression insensitive to normal causes of uncertainty in optical measurements such as variations in focal plane, cell concentration, and turbidity.Normal Raman signals from cells and their infrared (FTIR) absorbance patterns have been previously used to differentiate between cancer and normal cells (6-9). SERS has been used as an alternative immunohistochemistry (IH...

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mentioning

confidence: 99%

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Pallaoro

Braun

Moskovits

2011

Proc. Natl. Acad. Sci. U.S.A.

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“…New Raman bands appeared in the region between 1150 and 1700 cm −1 , related to base structures and base-pairing, with higher intensities than the peaks in the spectra of the untreated cells. It has been shown that bands assigned to localised vibrations of these bases exhibit pronounced intensity increases during DNA melting [21]. The peaks in this region which showed hyperchromic behaviour are 1340, 1487 and 1578 cm −1 representing purine bases and 1378 cm −1 representative of pyrimidine bases [8], [21] and [22].…”

Section: Impact Of Increasing Concentrations Of Ethanolic Extract Of mentioning

confidence: 99%

“…It has been shown that bands assigned to localised vibrations of these bases exhibit pronounced intensity increases during DNA melting [21]. The peaks in this region which showed hyperchromic behaviour are 1340, 1487 and 1578 cm −1 representing purine bases and 1378 cm −1 representative of pyrimidine bases [8], [21] and [22]. A peak appeared at 1262 cm −1 , which is usually attributed to protonated cytosine, but the amount of plant extract used could not have lowered the pH to such an extent as to protonate cytosine [14].…”

Section: Impact Of Increasing Concentrations Of Ethanolic Extract Of mentioning

confidence: 99%

A micro-Raman spectroscopic investigation of leukemic U-937 cells treated with Crotalaria agatiflora Schweinf and the isolated compound madurensine

Roux

Prinsloo

Hussein

et al. 2012

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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In South Africa traditional medicine plays an important role in primary health care and therefore it is very important that the medicinal use of plants is scientifically tested for toxicity and effectiveness. It was established that the ethanolic extract of the leaves of Crotalaria agatiflora, as well as the isolated compound madurensine, is moderately toxic against leukemic U-937 cells. The investigation showed that micro-Raman spectroscopy has great promise to be used for initial screening of samples to determine the effects of different treatments on cancerous cell lines together with conventional methods. The results highlight the fact that for many natural products used for medicinal purposes, the therapeutic effect of the crude plant extract tends to be significantly more effective than the particular action of its individual constituents. Graphical abstractLeukemic U-937 cells were treated with different concentrations of the ethanolic extract of Crotalaria agatiflora subspp. agatiflora and the isolated pyrrolizidine alkaloid, madurensine.Different biochemical responses were observed with micro-Raman spectroscopy after treatments. Highlights Crotalaria agatiflora Schweinf has an ethnobotanic use against cancer.  An ethanolic extract of the plant was tested against leukemic U-937 cells.  Raman spectra showed changes in cell morphology and biochemical constituents.  Crude plant extracts might be more bioactive than isolated compounds.  Raman spectroscopy has potential as an initial screening tool in phytomedicine.

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“…To enhance our ability to resolve SERS spectra more efficiently, we evaluated Principal Component Analysis (PCA), an approach often used to reduce the dimensionality of spectroscopic data (18)(19)(20), to resolve our four SERS tags. Spectra acquired from the Raman Spectral Flow Cytometer were smoothed, normalized and the first derivative calculated and subjected to PCA.…”

Section: Multivariate Statistical Approaches To Resolving Raman Spectmentioning

confidence: 99%

A flow cytometer for the measurement of Raman spectra

et al. 2008

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Multiparameter measurements in flow cytometry are limited by the broad emission spectra of fluorescent labels. By contrast, Raman spectra are notable for their narrow spectral features. To increase the multiparameter analysis capabilities of flow cytometry, we investigated the possibility of measuring Raman signals in a flow cytometry-based system. We constructed a Raman Spectral Flow Cytometer, substituting a spectrograph and CCD detector for the traditional mirrors, optical filters, and photomultiplier tubes. Excitation at 633 nm was provided by a HeNe laser, and forward-angle light scatter is used to trigger acquisition of complete spectra from individual particles. Microspheres were labeled with nanoparticle surface enhanced Raman scattering (SERS) tags and measured using the RSFC. Fluorescence and Raman spectra from labeled microspheres were acquired using the Raman Spectral Flow Cytometer. SERS spectral intensities were dependent on integration time, laser power, and detector pixel binning. Spectra from particles labeled with one each of four different SERS tags could be distinguished by either a virtual bandpass approach using commercial flow cytometry data analysis software or by principal component analysis. Raman flow cytometry opens up new possibilities for highly multiparameter and multiplexed measurements of cells and other particles using a simple optical design and a single detector and light source. ' 2008International Society for Analytical Cytology

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Raman Microscopy for the Chemometric Analysis of Tumor Cells

Cited by 97 publications

References 26 publications

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression

A micro-Raman spectroscopic investigation of leukemic U-937 cells treated with Crotalaria agatiflora Schweinf and the isolated compound madurensine

A flow cytometer for the measurement of Raman spectra

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