Potential of ‘flat’ fibre evanescent wave spectroscopy to discriminate between normal and malignant cells in vitro

Abstract

SummaryThe present study focuses on evaluating the potential of flattened AgClBr fibre-optic evanescent wave spectroscopy (FTIR-FEWS) technique for detection and identification of cancer cells in vitro using cell culture as a model system. The FTIR-FEWS results are compared to those from FTIRmicrospectroscopy (FTIR-MSP) method extensively used to identify spectral properties of intact cells. Ten different samples of control and malignant cells were measured in parallel by the above two methods. Our results show a significant similarity between the results obtained by the two methodologies. The absorbance level of Amide I/Amide II, phosphates and carbohydrates were significantly altered in malignant compared to the normal cells using both systems. Thus, common biomarkers such as Amide I/Amide II, phosphate and carbohydrate levels can be derived to discern between normal and cancer cells. However, marked differences are also noted between the two methodologies in the protein bands due to CH 3 bending vibration (1480-1350 cm −1 ). The spectral differences may be attributed to the variation in the penetration depth of the two methodologies. The use of flattened fibre rather than the standard cylindrical fibre has several practical advantages and is considered as an important step towards in vivo measurements in real time, such as that of skin nevi and melanoma using special designs of fibre-optic-based sensors.

Chemometrics of Cells and Tissues Using IR Spectroscopy - Relevance in Biomedical Research

“…Complicated tissues like colonic epithelium present two possibilities of data acquisition, along the cross section (Argov et al 2002 or longitudinal section (Sahu et al 2004b(Sahu et al , 2010 of the crypts and inevitably the availability of microscopic or FPA facilities. Understanding the spectral differences due to instrumentation has been undertaken with the objective of tailoring the techniques to suit set ups and also verifying the universal applicability of certain parameters compared to others (Hammody et al 2007).…”

“…Usually the normal or abnormal class is given a final value of 100 and its reverse condition the value of zero by using a combination of weighted coefficients. The different intermediary stages lie within these two extreme values (Hammody et al 2007, Bogomonly et al 2009. One or more of the statistical and computational methods can be resorted to classify samples when an ambiguity is encountered.…”

“…In case of measurement along the length of the crypt the replication is carried out by measuring several crypts at similar distance form the base or apex unlike the cross section where several crypt circles are measured. For more complex tissues such as skin, where different kinds of abnormalities occur (both benign and malignant) the exact location of the sample measurement area requires the involvement of an expert dermatologist/pathologist to pin point and mark the areas on the complementary slides (Hammody et al 2007). Advancement in technologies have made it possible to automatically measure entire regions of the biopsy using the FPA detector systems and the spectra corresponding to every pixel of the measured area can be obtained.…”

“…The LDA and PCA techniques classify biopsies into several groups presenting them in normal graphical formats and assigning the grade. The DCF analysis improves discrimination between different stages by using a weighted value for each biomarker used and enables proper assignment during studies involving progression of changes in cells and tissues (Hammody et al 2007, Bogomonly et al 2009.…”

Surface enhanced Raman spectroscopy and its application to molecular and cellular analysis

“…Of the numerous different implementations: surface enhanced Raman spectroscopy or SERS (Liu et al 2007; Kneipp et al 2005), surface plasmon resonance or SPR (Campagnolo et al 2004;Huang et al 2005), Fourier transform infrared spectroscopy or FT-IR (Riley et al 2006;Hammody et al 2007), and traditional fluorescent spectroscopy (Petrovsky et al 2003) have been recently applied to cancer diagnostics. Fluorescence detection is likely the one most commonly used for bimolecular detection because of its high sensitivity and low detection limits for biologically relevant species.…”