Stem cells have long received significant attention recently because of their pluripotency nature, which allows the cells to differentiate into all kinds of organs and tissues.

In theory, stem cells can regenerate any damaged cells and tissues, including muscles, bones, organs, and brain. However, there have been limitations to using stem cells as it is difficult to accurately control the differentiation process of stem cells transplanted into the human body.

To solve this problem, it is necessary to understand the survival, migration and distribution of stem cells accurately, and a local research team is drawing attention by developing a new technology that can accurately and securely track such changes in stem cells in vivo.

A team of researchers from the Korea Institute of Science and Technology (KIST) and Dongguk University Ilsan Hospital (DUIH) said that they had developed a new concept of stem cell labeling and imaging technology that tracks stem cells transplanted into the human body. Professors Kim Kwang-myung from KIST and Kim Dong-uk from DUIH led the study.

The technology can monitor the long-term composite image of fluorescence image and magnetic resonance imaging (MRI) by binding the biocompatible nanoparticles to stem cells. Such labeling and imaging techniques for observing the movement and distribution of stem cell therapeutics have recently attracted attention as a technique for tracking changes after stem cell transplantation.

However, conventional cell labeling had to convert the contrast agent or the nanoparticles containing the contrast agent directly into stem cells or convert them into cells capable of imaging through genetic manipulation. Such methods had concerns about stem cell-intrinsic pluripotency and human safety.

The joint research team used metabolic glycoengineering and bioorthogonal copper-free click chemistry to develop a new concept of labeling technology that is highly biocompatible and does not affect stem cell pluripotency.

“Through the technology, we made a chemical receptor that can safely label the surface of stem cells, and develop nano-oxide-based complex contrast agent nanoparticles that specifically bind to it,” the team said. “We were able to succeed in obtaining high sensitivity composite images to maximize the image signal of stem cells.”

The team could have reliable long-term observations for more than 14 days using near-infrared fluorescence and MRI images through experiments with stroke animal models.

“This became possible as the newly developed complex contrast agent nanoparticle and stem cell labeling technology minimized the loss of pluripotency of stem cells and the expression of cytotoxicity,” the team said.

Professor Kim said, “The stem cell labeling and tracking technology we recently developed allows the long-term follow-up of the therapeutic effect of stem cells transplanted into the brain through a high sensitivity composite image.”

The team expects that the technology will be widely used for the development of stem cell therapeutics for brain diseases, Kim added.

The results of the research were published in ACS Nano.

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