January 27, 2004
Scientists Grow Neurons Using Nanostructures
EVANSTON, Ill. --- Scientists at Northwestern University have
designed synthetic molecules that promote neuron growth, a promising
development that could lead to the reversal of paralysis due to
spinal cord injury.
“We have created new materials that because of their chemical
structure interact with cells of the central nervous system in
ways that may help prevent the formation of the scar that is often
linked to paralysis after spinal cord injury,” said Samuel
I. Stupp, Board of Trustees Professor of Materials Science and
Engineering, Chemistry and Medicine.
Similar to earlier experiments that promoted bone growth, the
scientists now have successfully grown nerve cells using an artificial
three-dimensional network of nanofibers, an important technique
in regenerative medicine. The results were published online by
the journal Science.
“We have shown that our scaffold selectively and rapidly
directs cell differentiation, driving neural progenitor cells to
become neurons and not astrocytes,” said Stupp, who led the
research team in Evanston. “Astrocytes are a major problem
in spinal cord injury because they lead to scarring and act as
a barrier to neuron repair.”
The innovative
scaffold is made up of nanofibers formed by peptide amphiphile
molecules. The scientists’ key breakthrough was
designing the peptide amphiphiles so that when they self-assembled
into the scaffold a specific sequence of five amino acids known
to promote neuron growth were presented in enormous density on
the outer surfaces.
“This was all done by design,” said Stupp, who is
also director of the University’s Institute for Bioengineering
and Nanoscience in Advanced Medicine. “By including a specific
biological signal on the nanostructure we were able to customize
the new materials for neurons.”
In collaboration with the lab of John A. Kessler, Benjamin and
Virginia T. Boshes Professor of Neurology at the Feinberg School
of Medicine, Stupp and his team observed that when the peptide
amphiphiles were placed in solution and combined with neural progenitor
cells (which are present in the central nervous system and able
to differentiate into different types of cells) the nanofiber scaffolds
formed and led quickly to the selective differentiation of the
cells into neurons.
In subsequent experiments, the researchers successfully delivered
the peptide amphiphile solution, using a simple injection, to the
site of a spinal cord injury in a laboratory rat. Upon contact
with the tissue, the solution was transformed into a solid scaffold.
In addition to Stupp and Kessler, other authors on the Science
paper are Gabriel A. Silva and Catherine Czeisler (lead authors),
Krista L. Niece, Elia Beniash and Daniel Harrington, all from Northwestern
University. The research was supported by the National Science
Foundation, the National Institutes of Health and the U.S. Department
of Energy. |