Spectral analysis of laser-induced ultraweak delayed luminescence in cultured normal and tumor human cells: temperature dependence

Time‐resolved spectral measurements of delayed luminescence from a single soybean seed: effects of thermal damage and correlation with germination performance

“…Every point represents DL intensity emitted around a certain wavelength λ em , integrated in the whole time acquisition window, and normalized to the sum of the spectral components. The relative number of re-emitted photons increases for wavelengths moving toward the red and near-infrared, according to previous results from other systems, [31,32] nonetheless in this case a local maximum emerges in the green-yellow region of the spectrum.…”

“…The latter value is consistent with our hypothesis on DL origin in the case of dehydrated seeds where only exciton-like collective excitations could be maintained, because the very low water content makes the structure more rigid. In this case according to eqn (5) and taking into account that, due to the sensitivity factor of the experimental set-up, [31] the wavelength at which the filter emission has its maximum is slightly lower than the nominal value, a theoretical value = 2.04 ± 0.20 is foreseen, in good agreement with the experimental result for devitalized seeds. On the other hand, in the case of the native seeds, one could consider the coexistence of the two kinds of collective excitation because the water content is probably not uniformly distributed in the biological structure inside the seed.…”

“…Complete emission spectra were collected only for a sub-set of single native and artificially aged seeds, in order to test if average DL spectral features changed with the thermal aging. To take into account the sensitivity of PMT at different wavelengths, raw data were processed taking into account the sensitivity factor of the apparatus, [31] that is the product of the optical transmittance of the filtering system and the quantum efficiency of the photomultiplier. Since from the time-dependent emission spectrum two main trends were distinguisged, only two representative spectral components (central wavelengths λ em = 460 and 645 nm respectively) were monitored for every seed in each of the seven samples (a total of about 90 seeds), in order to extract single-seed physical parameters that could be significantly correlated with germination properties.…”

Effects of Menadione, Hydrogen Peroxide, and Quercetin on Apoptosis and Delayed Luminescence of Human Leukemia Jurkat T-Cells

“…Having in view the growing interest of using delayed luminescence (DL) spectroscopy in clinical applications [28][29][30][31][32], a second goal of our study was to gain new insights into the biochemical mechanisms responsible for DL of living cells, as well as to provide new data regarding the relation between DL and the cell status. Thus, we have investigated, for the first time to our knowledge, the correlation between apoptosis, oxidative stress, and DL.…”

“…Moreover, our data are consistent with an important role of MRC Complex I in delayed photoemission and indicate that superoxide is a powerful quencher of DL. Nevertheless, further studies are needed to characterize the exact relation between DL and the mitochondrial respiratory system, but the progresses achieved in promoting DL spectroscopy as a valuable tool in the diagnosis of mitochondrial disorders or cancer [28][29][30][31][32] point to the critical need for such investigations.…”