Evaluation of the effects of both photosensitizers and quenchers of singlet oxygen on HeLa cells using Synchrotron Infrared Microscopy?

GABRIELA BOSIO; DANIEL MARTIRE; FERNANDO GARCÍA EINSCHLAG

Congreso; XII Encuentro Latino-Americano de Fotoquímica y Fotobiología (ELAFOT); 2015

In order to better understand the PDT mechanism, synchrotron infrared microscopy was used to detect the associated intracellular biochemical modifications following the irradiation of HeLa cells incubated with β-carotene or imidazole as typical hydrophobic and hydrophilic quenchers, respectively. For this purpose, Photodynamic Therapy (PDT) at many concentrations of the quenchers was performed. The use of the synchrotron source allows the analysis of biological components in the cell at subcellular resolution. The IR spectra of PDT-treated, PDT plus quencher-treated and control HeLa cells were recorded at the SOLEIL Synchrotron Infrared beamline targeting specifically the cell nucleus. Principal component analysis (PCA) has been used to assess the IR spectral changes between the various HeLa cells spectral data sets (The Unscrambler software, CAMO). PCA revealed that there is a frequency shift of protein amide I and amide II vibrational bands, indicating changes in the protein secondary structures of the PDT-treated cancer cells compared to the control cells. In addition, the scores in those cells treated with any quencher appear to be similar to the controls indicating a photoprotective effect.