Technology.am (Sept. 21, 2009) — Researchers have devised an implantable device that combines magnetism with nanotechnology, which would allow patients or their physicians to determine exactly when drugs are delivered, and in what quantities.
Researchers led by Daniel Kohane, MD, PhD of Children’s Hospital Boston, have created a small implantable device, less than ½” in diameter that encapsulates the drug in a specially engineered membrane, embedded with nanoparticles composed of magnetite, a mineral with natural magnetic properties.
When a magnetic field is switched on outside the body near the device, the nanoparticles heat up causing the gels in the membrane to warm and temporarily collapse.
This opens up pores that allow the drug to pass through and into the body. When the magnetic force is turned off, the membranes cool and the gels re-expand, closing the pores back up and halting drug delivery. No implanted electronics are required.
They have tested this experiment on animals, where drug delivery could be turned on with only a 1 to 2 minute time lag before drug release, and turned off with a 5 to 10 minute time lag. The membranes remained mechanically stable under tensile and compression testing, indicating their durability, showed no toxicity to cells, and were not rejected by the animals’ immune systems. They are activated by temperatures higher than normal body temperatures, so would not be affected by the heat of a patient’s fever or inflammation.
The device, which Kohane’s team is continuing to develop for clinical use, is described in the journal Nano Letters. The study was funded by the National Institutes of Health’s National Institute of General Medical Sciences (NIGMS).
While some distance away from use in humans, this technology has the potential to provide precise, repeated, long-term, on-demand delivery of drugs for a number of medical applications, including the management of pain.