Process could be an Earth-based alternative to space missions
The increased application of the principles of physics to the study of biological life is providing new details on the workings of molecules and other structures. A team of Brown scientists have married physics and biology in their use of a magnetic field to levitate embryos of a small frog. The maneuver produced a near zero-gravity condition, suggesting an Earth-based alternative to expensive space missions for observing how living plants and animals develop in a low-gravity environment.
The Brown scientists think that use of the technique, called magnetic field gradient levitation (MFGL), could allow researchers on Earth to perform experiments in simulated low gravity at a fraction of the cost of doing the work in a space shuttle. However, the scientists are unsure of the exact impact on plants and animals examined under the MFGL technique. In a study, the magnetic field caused changes in the early development of almost half of the frog embryos.
Valles and Kimberly Mowry are co-leaders of the research. Mowry is an assistant
professor in the Department of Molecular Biology, Cell Biology and
Biochemistry. Because the University deemed their research to be of exceptional
merit, Valles and Mowry were recently named Richard B. Salomon Faculty Research
Award winners for the 1997-98 academic year. A total of $250,000 was dispersed
for projects pursued by the 23 award winners. Valles and Mowry will use their
award to study the effects of the magnetic field on the early development of
the frog.
The levitation study has been accepted for publication in the Biophysical
Journal. The scientists first described their findings at the March 1996 annual
meeting of the American Physical Society. Their study marked the first account
of living creatures levitated in a magnetic field. Last April, researchers in
the Netherlands reported use of a magnetic field to levitate a frog,
grasshoppers, fish and plants.
The Brown scientists created the magnetic field inside a large bagel-shaped
solenoid - a cylindrical coil of tightly wound insulated wire through which a
powerful electric current flowed. The solenoid was about 20 inches tall and 30
inches in diameter, with a 2-inch-diameter center hole. Up to 100 embryos -
each the thickness of paper clip metal --were placed one by one in a drop of
pure water levitated in a magnetic field created by five megawatts of
electricity.
The procedure worked because the water, proteins and lipids inside the embryos
created a weak magnetic field that repelled them slightly from the powerful
field inside the solenoid. The result was a force that levitated the
embryo-laden drop inside the solenoid.
The technique reduced both the body forces and the gravity-induced stresses on
the frog embryos by a factor of 10, which simulated a near-weightless
environment. No other ground-based technique has produced a similar reduction
in forces and stresses.
"This could even be a way for scientists to perform a range of preliminary
experiments relative to zero gravity to decide which ones would be more
important for including in a space shuttle mission," said James M. Denegre, a
member of the research team and a postdoctoral researcher in the Department of
Molecular Biology, Cell Biology and Biochemistry. "For example, several types
of plants or body-tissue cultures would fit nicely in the solenoid."
Valles said that work by physics professor Humphrey Maris and colleagues to
levitate superfluid helium is the foundation of the current research.