Photodynamic therapy of HeLa cell cultures by using LED or laser sources

GARAVAGLIA MARIO; MIGUEL ANGEL PASQUALE; ETCHEVERRY, MARIA EUGENIA

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2016 vol. 160 p. 271 - 277

1011-1344

The photodynamictherapy (PDT) on HeLa cell cultureswas performed utilizing a 637 nm LED lamp with 1.06 W power and m-tetrahydroxyphenyl chlorin (m-THPC) as photosensitizer and compared to a laser source emitting at654 nmwith thesame power. Intracellular placement ofthephotosensitizerandthe effect of its concentration (CP),itsabsorptiontime(TA)andtheilluminationtime(TI)wereevaluated.ItwasobservedthatforCP N 40μg/ml and TA N 24 h, m-THPC had toxicity on cells in culture, even in the absence of illumination. For the other tested concentrations, the cells remained viable if not subjected to illumination doses. No effect on cells was observed for CP b 0.05 μg/ml, TA = 48 h and TI = 10 min and they continued proliferating. For drug concentrations higher than 0.05 μg ml−1, further deterioration is observed with increasing TA and TI. We evaluated the viability of the cells, before and after the treatment, and by supravital dyes, and phase contrast and fluorescence microscopies, evidence of different types of cell death was obtained. Tetrazolium dye assays after PDT during different times yielded similar results for the 637 nm LED lamp with an illuminance three times greater than that of the 654 nm laser source. Results demonstrate the feasibility of using a LED lamp as alternative to laser source. Here the main characteristic is not the light coherence but achieving a certain light fluence of the appropriate wavelength on cell cultures. We conclude that the efficacy was achieved satisfactorily and is essential for conve-nience, accessibility and safety.