Use Magnetic Fields, Rather Than Drugs

Magnetic Jewelry Clasp

At left, cells were pre-coated with tiny magnetic beads, each binding to a cell receptor (see arrows). When a magnetic field is applied (at right), the beads become magnets and cluster together, pulling the receptors with them. This clustering mimics what happens when drugs or other molecules bind to the receptors, triggering the same biochemical responses in the cell. (Credit: Image courtesy Don Ingber, PhD, Children's Hospital Boston)

Researchers at Children's Hospital Boston have developed a new "nanobiotechnology" that enables magnetic control of events at the cellular level

Don Ingber, MD, PhD, and Robert Mannix, PhD, of Children's program in Vascular Biology, in collaboration with Mara Prentiss, PhD, a physicist at Harvard University, devised a way to get tiny beads--30 nanometers (billionths of a meter) in diameter--to bind to receptor molecules on the cell surface. When exposed to a magnetic field, the beads themselves become magnets, and pull together through magnetic attraction. This pull drags the cell's receptors into large clusters, mimicking what happens when drugs or other molecules bind to them. This clustering, in turn, activates the receptors, triggering a cascade of biochemical signals that influence different cell functions.

The technology could lead to non-invasive ways of controlling drug release or physiologic processes such as heart rhythms and muscle contractions, says Ingber, the study's senior investigator. More importantly, it represents the first time magnetism has been used to harness specific cellular signaling systems normally used by hormones or other natural molecules.

The nanomagnetic system could also interface with external instruments and computer controls that take in information from the body or the surrounding environment and activate the magnet as needed, Ingber adds.

A diabetic, for example, could have a transdermal glucose sensor that controls the magnet, which then controls the insulin production by itself. In the neonatal intensive care unit, sick newborns could have their heart and breathing rates monitored and their cells rigged to respond through magnetic stimulation, without a tangle of wires and probes. Or, on the battlefield, the magnet could trigger production of an antidote when a toxin or infectious agent is sensed in the environment.

The study was supported by a Defense Advanced Research Projects Agency (DARPA) grant from the Department of Defense and an NIH postdoctoral fellowship.