The proof-of-concept experiments
were done on glass, not in the body. The
researchers grew cells on QD films so
that their membranes were close to the
QD-coated surfaces. When light excites
electrons in the QDs, they generate
a magnetic field, which then triggers
measurable changes in the ion-channel
activity on the cell surface.
They used cadmium-telluride and
cadmium-selenium QDs to investigate
prostate cancer cells first (because of
their resilience) and then brain neurons.
The researchers observed that the ion
channels in the cancer and brain cell
membranes were activated when the
QDs were excited.
Researchers need to identify a nontoxic material for QDs before they
can be used in vivo. But the technique
developed by Reike and Lin’s team offers
the potential to manipulate the activity
Lugo et al., University of Washington.
Optically excited quantum dots in close proximity
to a cell control the opening of ion channels.
of specific types of neurons, which could
elucidate—or even be used to treat—
brain diseases. “Many brain disorders
are caused by imbalanced neural activ-
ity,” Rieke says. “This could aid both
in understanding the normal activity
patterns in neural circuits, by introduc-
ing perturbations and monitoring their
effect, and how such manipulations
could restore normal circuit activity.”
ONLINE EXTRA: Visit www.osa-opn.org for weekly news updates.
Patricia Daukantas ( patd@nasw.org) and
Yvonne Carts-Powell ( yvonne@nasw.org) are
freelance science writers who specialize in
optics and photonics.
