Optical imaging of intracellular reactive oxygen species for the assessment of the cytotoxicity of nanoparticles

Kyuri Lee, Hyukjin Lee, Kun Woo Lee, Tae Gwan Park

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


The generation of intracellular reactive oxygen species (ROS) was optically monitored using ROS-sensitive gold nanoprobes in response to an exposure of nanoparticles (NPs). Fluorescent dye-labeled hyaluronic acid was grafted onto the surface of gold nanoparticles (HF-AuNPs) for imaging intracellular ROS. The ultrasensitive detection of intracellular ROS was utilized as a powerful analytical tool to assess early cellular toxicities of monodisperse polystyrene (PS) particles with different sizes and different functional groups on the surface. The effect of PEGylation on the surface of PS NPs was also investigated by evaluating intracellular ROS generation. For various PS NPs, the extent of intracellular ROS was well correlated with cellular uptake, apoptosis inducing activity, and cytotoxic effect of NPs. In addition to the nanoparticles, commonly used polymeric gene carriers such as linear and branched polyethylenimine (PEI) were tested to analyze their extent of intracellular ROS generation related to cellular toxicity. This study demonstrated that sensitive and optical detection of intracellular ROS generation can provide a valuable toxicity index value for a wide range of NPs as an early indicator for cellular responses.

Original languageEnglish
Pages (from-to)2556-2565
Number of pages10
Issue number10
StatePublished - Apr 2011

Bibliographical note

Funding Information:
This study was supported by the National Research Laboratory, Basic Science Research Program (2010-0027955), and WCU program through the National Research Foundation (NRF) grants from the Ministry of Education, and Science and Technology, Republic of Korea .


  • Gold nanoprobes
  • Nanotoxicity
  • PEGylation
  • Poly(ethylenimine)
  • Reactive oxygen species (ROS)


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