Scientists have taken what may be a key
step toward creating human organs such as livers and kidneys.
Taking their cue from the body's own vascular system, researchers
from M.I.T. and Harvard Medical School constructed a microscopic
device capable of supplying oxygen and nutrients to organ
cells.
Recent efforts to grow new organs have met with limited
success. Whereas researchers have managed to make skin
and cartilage, functional vital organs have eluded them.
The problem, explains M.I.T.'s Mohammad Kaazempur-Mofrad,
is that although conventional tissue engineering methods
provide a scaffold for the cells of the tissue, they do
not offer the vascular support necessary to nourish organs
such as livers and kidneys.
To address that problem, Kaazempur-Mofrad
and his colleagues used fractal computational
models to design networks mimicking the intricate
branching pattern of actual blood vessels. They then
etched those nano networks onto silicon surfaces, which
in turn served as molds for biocompatible polymer films.
The next step was to sandwich a microporous membrane
between two films and seal them together.
"Our microfabricated
devices can efficiently supply oxygen and nutrients
to sustain the viability of human liver and kidney cells
for at least one week in the lab," Kaazempur-Mofrad
reported yesterday at the American Society for Microbiology's
conference on Bio- Micro- Nano-systems in New York City.
In experiments, 96 percent of kidney cells incorporated
into the artificial vascular network lived for one week;
95 percent of liver cells survived for two weeks. A
liver system implanted into rats lasted a week.
