drug delivery systems

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.

In 1941, researchers at Johns Hopkins Hospital made an unsettling discovery: Inhaled nanoscopic particles could travel into the brain. When chimps and rhesus monkeys breathed air laden with poliovirus cells, some of the particles followed the path normally reserved for smell signals, thwarting the protective blood-brain barrier.