Nanotechnology Advances May Transform Regenerative Medicine

Researchers are utilizing nanotubes to transform adult stem cells into neurons in brain-damaged rats. Carbon nanotubes--80,000 times thinner than a human hair--have been shown to enhance the ability of adult stem cells to differentiate into healthy neurons in stroke-damaged rat brains, according to American and South Korean researchers.

Thomas Webster, Ph.D., from Brown University (Providence, RI, USA) and colleagues at Yonsei University (Seoul, Korea), combined nanotubes with adult rat stem cells and then implanted the mixture into brain-damaged areas of three rats that had suffered strokes. In six other rats that had strokes, they implanted either adult stem cells or nanotubes, but not both, into brain-injured regions.

After tracking the rats for up to eight weeks, the researchers concluded that neither nanotubes nor adult stem cells alone activated regeneration or repair in the brain-damaged regions. In reality, when used alone, adult stem cells migrated to healthy areas of the brain. However, when combined with nanotubes, adult stem cells not only remained in the brain-damaged regions, they started to differentiate into functioning neurons. This finding could have significant implications for the treatment of Alzheimer's, Parkinson's disease, and other neurologic disorders, according to Dr. Webster.

In a similar study, researchers injected nanoparticles into the hearts of mice that suffered heart attacks, which helped restore cardiovascular function in these animals, according to Samuel Stupp, Ph.D., chemist and director of the Institute of Bionanotechnology in Medicine at Northwestern University (Evanston, IL, USA). This discovery is an important research development that one day could help rapidly restore cardiovascular function in individuals who have heart disease, according to Dr. Stupp.

The self-assembling nanoparticles--composed from naturally occurring polysaccharides and molecules known as peptide amphiphiles--enhance chemical signals to neighboring cells that trigger formation of new blood vessels, and this may be the mechanism through which they restore cardiovascular function.

One month later, the hearts of the treated mice were capable of contracting and pumping blood almost as well as healthy mice. In contrast, the hearts of untreated mice contracted about 50% less than normal. In other recent studies using a similar technique, Dr. Stupp and his colleagues discovered that nanoparticles accelerate wound-healing in rabbits, and after islet transplantation, cured diabetes in mice. Nanoparticles used with other chemical compounds were found to hasten bone repair in rats and promote the growth of neurons in mice and rats with spinal cord injuries, according to Dr. Stupp.



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Brown University
Yonsei University