The Korea Institute of Science and Technology (KIST) has developed a new imaging technology that allows researchers to monitor stem cells transplanted into a mouse body visually. The technology is expected to be widely used in developing stem cell therapeutic treatments and forecasting their efficacy.
The institute’s theragnosis research team led by Kim Kwang-myeong reported on Nov. 7 that they have observed changes of the mouse’s stem cells that were bound with contrast agents for 14 days by using fluorescence image and magnetic resonance imaging (MRI).
The KIST team suggested in 2017 a method of attaching nanoparticles to the surface of transplanted stem cells, instead of injecting contrast agents into the stem cells in order to track the fate of the transplanted stem cells. They used polymeric glycol chitosan as a material of nanoparticles.
Stem cells are omnipotent cells that can differentiate into various cell types and a growing number of studies have been carried out to regenerate damaged tissues by using stem cells. Stem cells themselves can be implanted in animal or human bodies to regenerate impaired tissues. This requires an evaluation technology to monitor whether the implanted stem cells are staying in a target tissue and work properly. Presently, MRI and other imaging tools are often used for imaging of stem cells and in that process contrast agents are added in stem cells. However, agents can change the original properties of stem cells and labeling efficacy is not good enough.
This time, Kim and his teammates optimized properties of the nanoparticles that they had developed two years ago. They added 20-nm iron oxide nanoparticles with excellent imaging performance to glycol chitosan nanoparticles.
The KIST team demonstrated the imaging efficacy by administering iron oxide-based nanoparticles to a stroke mouse. “We labeled transplanted stem cells of a stroke mouse with contrast agent nanoparticles and could observe reliably for 14 days by using near-infrared fluorescence and MRI images,” explained Dr. Kim.
The results of the research were published in the Oct. edition of the American Chemistry Society (ACS) Nano.