High throughput absorbance spectra of cancerous cells: a microscopic investigation of spectral artifacts

Abstract

FTIR spectroscopy was recently demonstrated to be a useful tool to obtain a unique fingerprint of the effects of several anticancer drugs on cells in culture. While FTIR spectroscopy appears to have a definite potential to sort anticancer drugs on the basis of the metabolic modifications they induced, the present challenge is to evaluate the drug-induced spectral changes in cancer cells on a larger scale. The coupling of FTIR spectroscopy with a high throughput screening extension could become a useful method to generate drug classifications based on their "modes of action". Practically, the robustness of this approach is jeopardized by the variability that can appear from one cell smear to the next. When a few cells are scattered on the support, strong scattering effects are observed and locally dense cell aggregates could result in non-linearity of the signal. A microscopic study using infrared imaging demonstrates that the mean HTS (96-well High Throughput Spectroscopy) spectra recorded on 96 well ZnSe plates are the averages of contributions characterized by a wide absorbance distribution and by Mie scattering effects which significantly vary from point to point. Spectrum quality is at its best at the highest cell concentrations, i.e. from 300 000 to 400 000 cells per well, which present the best S/N and a relatively smaller Mie scattering effect. When the breast cancer cell line MDA-MB-231 was treated with four different polyphenols, spectra showed quite similar variations with respect to control spectra, with more intense variations for the quercetin and EGCG compared to resveratrol and capsaicin. Correction of the spectra with the RMieS algorithm improved their clustering according to the polyphenolic treatment.

Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) Spectroscopy Analysis of Saliva for Breast Cancer Diagnosis

“…FTIR spectroscopy is capable to show changes in carcinogenesisrelated vibrational modes to several human cancers [8,[12][13][14]. Specifically for breast cancer, FTIR spectroscopy has been used for many purposes [15][16][17][18][19][20][21][22][23][24], mainly for detection [4,[25][26][27][28]. Most FTIR spectroscopy studies in breast cancer used normal breast tissue and breast tumors [4,[29][30][31], breast cell lines [11,32,33], and blood of breast cancer patients [25,27].…”

Monitoring of plant–environment interactions by high‐throughput FTIR spectroscopy of pollen

“…; Kohler et al . ; Mignolet & Goormaghtigh ). An extension of this approach on studies of pollen would have a great potential, particularly for comprehensive monitoring of terrestrial ecosystems.…”

“…As FTIR spectroscopy supports high-throughput measurements, the technique is ideal for rapid screening of plant populations under different conditions. A high-throughput screening (HTS) FTIR system has been successfully applied in a variety of studies in natural and biomedical sciences for the investigation of microorganisms and tissues (Dean et al 2010;Sirikwanpong et al 2010;Ollesch et al 2013;Kohler et al 2015;Mignolet & Goormaghtigh 2015). An extension of this approach on studies of pollen would have a great potential, particularly for comprehensive monitoring of terrestrial ecosystems.…”

Miniature diamond-anvil cells for FTIR-microspectroscopy of small quantities of biosamples

“…Yet, by sampling as a film and using an anvil, it was possible to analyze significantly lower amounts of biosamples, compared to that for HTS-XT. To record spectra with HTS-XT on a 384 well (each 5 mm in diameter) microplate ∼2 × 10 5 cells were needed 24 while only about 2 × 10 3 cells were required for FTIR-microscopy of a dried compressed film. To record tumour cell spectra by ATR-FTIR spectroscopy ∼5 × 10 6 cells were seeded directly on a ZnSe crystal with a 6.25 cm 2 surface.…”