Sensor and assay for screening of photosensitizers in living cells


Project ID:  D2018-33



Photodynamic therapy (PDT) uses light and a photosensitizer in the presence of oxygen to elicit cell death. This technique has been under investigation for use in treatment of cancer

Most often used to treat skin cancer, mycosis fungoides, and non-small cell lung cancer.

Researchers need to detect the ability of PDTs to disrupt cell signaling in order to develop a cancer treatment. Currently, researchers look at measurement of single oxygen (1O2) or ROS induced oxidation. However, 1O2 and ROS can be the result of other cellular activities. Therefore, there is a need to directly quantify the efficacy of photosensitizers to examine the efficacy of PDT agents in living cells


Invention Description

Researchers at the University of Toledo have developed an assay that allows for the visualization of the action of photosensitizes in living cells. As a research tool, this technology allows for high-throughput screening of photosensitizers, including Rose Bengal, Methylene Blue, FMN, FAD, and Retinal. In the presence of light, singlet oxygen is created by photosensizers the cells, and producing reactive oxygen species, ultimately perturbing membrane bound molecules. This invention translates the perturbation of signaling molecules in cells to a fluorescence signal that can be easily detected using imaging plate reader.



Screening for efficacy of photosensitizers and visualization of membrane bound signaling molecule perturbation in living cells.



•       Direct measure rather than measure of by-products

•       Detects influence photosensitizers on natural biomolecules in cells

•       Allows for measure of optimum chemical and light doses for PDT


Publications:        Ratnayake K, Payton JL, Lakmal OH, Karunarathne A.  Blue light excited retinal intercepts cellular signaling. Sci Rep. 2018 Jul 5;8(1):10207



Patent Information:
For Information, Contact:
Katherine Pollard
Licensing Associate
The University of Toledo
Welivitiya Karunarathne
Kasun Ratnayake
Photodynamic therapy