Detection of Ultraweak Photon Emission (UPE) from Cells as a Tool for Pathological Studies

Objective: It is well-known that all living cells emit ultra-weak photon emission (UPE), which is due to byproducts of chemical reactions in cell metabolisms. It has been shown that Reactive Oxygen Species (ROS) in the cells enhances the UPE intensity. The magnitude of such UPE is extremely weak (i.e. a few to 103 photons/ (sec.cm2)), and the detection of such ultra-weak signals is hardly possible via sensitive instruments like photomultiplier tube (PMT) that can detect single photons.Materials and Methods: H2O2 factor with various concentrations was applied on the HT-29 cells to generate ROS. H2O2 concentrations were so low to be nondestructive to the cells. Then, the effect of ROS generation on UPE intensity was investigated. PMT was used to detect UPE from HT-29 cells.Results: The topical application of H2O2 was significantly different (P < 0.05) in comparison with HT-29 cells without H2O2 at a concentration of 1mM in 5 min detection time. The integrated UPE in the presence of H2O2 at concentration of 3mM was significantly higher (P < 0.05) than the integrated UPE in other groups at the same detection time. The difference between the concentrations of 3mM and 4mM was not significant (P > 0.01) for integrated UPE in the cell groups in the presence of H2O2.Conclusion: The results show that the recorded UPE from HT-29 cells increased with the topical application of exogenous ROS inducer. As a result, UPE can be used as a non-invasive technique for monitoring ROS in cells.