For patients with conditions like cancer, diabetes and chronic pain, taking drugs orally is often insufficient; a more precise and flexible on/off dosing schedule controlled by an implanted device can provide better treatment based on day-to-day--or minute-by-minute--conditions.
While various methods for regulating drug-dispensing implants exist (including implanted heat sources and electronic chips), a new device with a membrane of magnetic nanoparticles can be controlled simply by applying a magnetic field.
Researchers led by Daniel Kohane, MD, PhD of Children's Hospital Boston, funded by the National Institutes of Health, have created an implantable device that envelops medication in a membrane laced with nanoparticles composed of magnetite (a naturally magnetic mineral). The nanoparticles heat up when activated by a magnetic field outside of the body which warms the membrane and causes its gels to temporarily collapse, allowing the drugs to pass through into the body. The membrane re-expands when the magnetic field is turned off and the gel cool, cutting off the dose.
The gel membranes have not, in animal experiments, shown any sign of degradation over time; dosage sizes and release rates remained consistent after multiple dose releases after 45 days of use. The membranes were also not rejected by the animals' bodies, and showed no signs of toxicity to nearby cells. Because the membranes are activated by temperatures higher than the human body's range, fevers would not inadvertently initiate drug release.
The device has not been tested on humans, but shows great potential for addressing the unique needs of patients who require medication in fluctuating doses and at irregular intervals.
The study's original article can be read here.