CH₂-Symmetric/CH₂-Antisymmetric Stretch Ratio Sensor for Cell Analysis

Abstract

Here we report on a novel infrared sensor system for measuring the CH₂-symmetric/CH₂-antisymmetric stretch ratio of cell samples. Based on IR absorbance spectra of healthy and malignant breast [1], blood [2] and brain [3] cells found in literature we hypothesized the possibility of disease stage cell discrimination by only comparing a few absorbance peaks in the lipid absorbance wavelength region between 3 and 4 μm. By comparing the lipid CH₂-symmetric and CH₂-antisymmetric stretch ratios (with baseline correction and normalization) of three defined epithelial kidney cell lines, healthy MDCK and carcinoma A-498 and Caki-1 with the developed sensor, significant stretch ratio differences have been found between healthy and tumor cell types (and even between the two tumor types). The developed LED-photodiode based infrared absorbance sensor could be used for quick pre-screening of biopsy samples which, compared to labeling and staining techniques, does not require highly trained personnel and is much cheaper than liquid nitrogen cooled FTIR spectroscopes.