A drug delivery device that uses magnetism and nanotechnology could be used to treat conditions such as chronic pain, cancer and diabetes.
The device has been developed by researchers at Children’s Hospital Boston in the US through funds from the National Institutes of Health.
The research team, led by Dr Daniel Kohane, has created a small implantable device, less than 1cm in diameter, that encapsulates a drug in a specially engineered membrane, embedded with nanoparticles composed of magnetite, a mineral with 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 up 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.
‘A device of this kind would allow patients or their physicians to determine exactly when drugs are delivered and in what quantities,’ said Kohane, who directs the laboratory for biomaterials and drug delivery in the department of anaesthesiology at the hospital.
In animal experiments, the researchers claim that the membranes remained functional over multiple cycles. The size of the dose was controllable by the duration of the ‘on’ pulse and the rate of release remained steady, even 45 days after implantation.
The team reported that testing indicated that drug delivery could be turned on with only a one- to two-minute time lag before drug release and turned off with a five- to 10-minute time lag.
It was also reported that the membranes remained mechanically stable under tensile and compression testing, indicating their durability. The membranes showed no toxicity to cells and were not rejected by the animals’ immune systems.
It was also noted that the membranes were activated by temperatures higher than normal body temperatures, so they would not be affected by the heat of a patient’s fever or inflammation.
‘This novel approach to drug delivery using engineered “smart” nanoparticles appears to overcome a number of limitations facing current methods of delivering medicines,’ said Alison Cole, who oversees anaesthesia grants at the National Institute of Health’s National Institute of General Medical Sciences.
‘While some distance away from use in humans, this technology has the potential to provide the precise, repeated, long-term, on-demand delivery of drugs for a number of medical applications, including the management of pain.’