Testing living cells’ influence on nanostructure growth — continued
Topographical confocal projections
of cells, which have integrated
onto predefined lipid-silica films.
The darker parts are the cells
that have redistributed the green
fluorescent lipid from the plane of
the thin film into three dimensions
around the cells.
(Slides by Eric Carnes)
Ordinarily, the drying of lipid-silica
solutions produces an ordered porous
nanostructure by a process known as
molecular self-assembly. This can be visualized
as a kind of tract housing. In the
current experiments, however, live yeast
or bacteria alter the construction process.
During drying, the cells actively organize
lipids into a multi layered cell membrane
that serves as an interface between the cell
and the surrounding silica nanostructure
and acts as a template, helping to direct
the formation of the surrounding silica
nanostructure.
This improved architecture seamlessly
retains water, needed by the cell to stay
alive. Further, by eliminating stresses
ordinarily caused by drying, the nanostructure
forms without fine-line cracks.
These improvements help maintain the
functionality of the cell and the accessibility
of its surface.
The cells are self-sustaining — they do
not need external buffers and even survive
being placed in a vacuum. To study
their use as cell-based sensors for extreme
environments, samples of the yeast- and
bacteria-containing nanostructures were
launched on the U.S. space shuttle Discovery.
On the International Space Station,
experiments are being performed to
determine cell longevity when exposed to
the radiation and vacuum of outer space.
Water reservoir
“Ordinarily, exposed to such extreme
conditions, the cells would turn into
raisins,” says Brinker. But previous testing
has shown “a remarkable coherency of the
cell-lipid-silica interface and the ability of
the lipid-silica nanostructure to serve as a
reservoir for water; no cracking or shrinkage
is observed. The cells are maintained in the
necessary fluidic environment.”
A quarterly research and development magazine.