Related Experiment Video
Updated: Jun 14, 2025

Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems
Published on: March 3, 2010
Generation of singlet oxygen inside living cells: correlation between phosphorescence decay lifetime, localization
Grzegorz Szewczyk1, Krystian Mokrzyński2, Tadeusz Sarna2
1Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland. grzegorz.szewczyk@uj.edu.pl.
Abstract:
Photodynamic therapy (PDT) is a promising alternative treatment for localized lesions and infections, utilizing reactive oxygen species (ROS) generated by photosensitizers (PS) upon light activation. Singlet oxygen (1O2) is a key ROS responsible for photodynamic damage. However, the effectiveness of PS in biological systems may not correlate with the efficiency of singlet oxygen generation in homogeneous solutions. This study investigated singlet oxygen generation and its decay in various cellular microenvironments using liposome and ARPE-19 cell models. Rose Bengal (RB), methylene blue (MB), and protoporphyrin IX (PpIX) were employed as selected PS. Lifetimes of singlet oxygen generated by the selected photosensitizers in different cellular compartments varied, indicating different quenching rates with singlet oxygen. RB, located near cell membranes, exhibited the highest phototoxicity and lipid/protein peroxidation, followed by PpIX, while MB showed minimal cytotoxicity in similar conditions. Singlet oxygen decay lifetimes provide insights into PS localization and potential phototoxicity, highlighting the importance of the lipid microenvironment in PDT efficacy, providing useful screening method prior to in vivo applications.
Related Concept Videos
Photoluminescence: Fluorescence and Phosphorescence
A pair of electrons in a...
Variables Affecting Phosphorescence and Fluorescence
Photoluminescence: Applications
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Deactivation Processes: Jablonski Diagram

