Time resolved sub-cellular singlet oxygen detection – ensemble measurementsversussingle cell experiments

Abstract

Systematic in vitro studies on singlet oxygen luminescence kinetics have been carried out reconciling recently published contradictory results reported for sub-cellular singlet oxygen kinetics obtained with two different approaches: single cell -and cell ensemble measurements. The singlet oxygen luminescence kinetics in two cell lines were investigated after incubation with three different photosensitizers. In each case a strong dependency of the singlet oxygen luminescence kinetics from the applied illumination already at very low doses was observed. Analysis of the obtained results allows judging the usability of the two approaches for detailed investigation of sub-cellular singlet oxygen kinetics. Intrinsically existing detection limits as well as local heating during the measurement will be discussed.

Photodynamic effects induced by meso-tris(pentafluorophenyl)corrole and its cyclodextrin conjugates on cytoskeletal components of HeLa cells

“…A cw Yb:YAG laser (Versadisk, ELS) equipped with a frequency doubling unit was used to excite the samples at 616 nm. The setup for detection of the luminescence signal has been reported previously [27,28]. To calculate the singlet oxygen quantum yield, F D , TPP in DMF was used as reference (F D ¼ 0.65) [29].…”

Singlet oxygen luminescence kinetics in a heterogeneous environment — identification of the photosensitizer localization in small unilamellar vesicles

“…On the other hand the radiative rate constant in the membrane is much bigger compared to the surrounding aqueous environment. 7 On the other hand the diffusion length of 1 O 2 in water is quite short. Based on the generally agreed value of the diffusion coefficient of oxygen in water D = 2 × 10 −5 cm 2 s −1 , 8,9 three dimensional diffusion results in an average diffusion length of just around 200 nm.…”

LEDs as excitation source for time resolved singlet oxygen luminescence detection in cell suspensions

“…The applied dose throughout a measurement should not exeed that. Consequently, already for our laser powered setup we reduced the illumination intensity to an average value of about 6mW at a repetition rate of 12 kHz (9,10). The diameter of the laser beam was about 3 mm.…”