Optimized Singlet Oxygen Detection System for Bioassays and Imaging

Nanoparticle That Optimizes Singlet Oxygen Detection  

Singlet oxygen (1O2) is a high-energy form of oxygen and its applications range from photodynamic therapy to biological assays. Tufts University investigator Samuel Thomas has developed a nanoparticle that optimizes the detection of 1O2 – an improvement that enables its ratiometric measurement and will extend its application to intracellular imaging. 

Features  high photon yield count • color emission • ratiometric response 

Applications • in vitro bioassays • intracellular imaging • high-resolution nanoscopy 


1O2 based detection systems currently rely on fluorescent probes for detection and yield a low photon count, thus emitting a weak signal. 1Oalso behaves like a sensor, the signal of which diminishes after a short period of time. Moreover, fluorescent probes that respond to 1O2 are not suitable for in vivo use.


Samuel Thomas’s nanoparticle technology responds uniquely to 1O2. In this configuration, the normal energy transfer from donor to acceptor particle is inhibited in the presence of 1O2. Consequently, while the light emission from the donor increases, the emission from the acceptor decreases over time. This enables a ratiometric and significantly accurate detection of 1O2

Competitive Advantage

Existing enzyme-based detection assays and current singlet oxygenbased assays are often single intensity technologies that result in less accurate readouts and lack an internal signal control. The ratiometric response in our technology address both these existing issues. Unlike a sensor, this signal behaves more like a dosimeter – building up over time. 


This is an excellent opportunity for companies seeking to improve accuracy in quantitative 1O2 bioassay products to measure
in vivo oxidation events and oxidative stress
• protein phosphorylation, cell signaling, and biomarkers 

This technology allows for the development of the following applications for the first time:
Use of singlet oxygen in intracellular imaging assays
• Improvements on detectable markers used in high-resolution nanoscopy

Intellectual Property

US Publication No. 2018-0036434 (February 8, 2018)

Tufts University Invention T002125


Licensing Contact

John Cosmopoulos