November 25, 2014
Imagine an electronic implant that delivers a drug when triggered by a remote wireless signal — then harmlessly dissolves (no post-surgical infection concerns, no fuss, no muss) within minutes or weeks.
That’s what researchers at Tufts University and the University of Illinois at Champaign-Urbana have demonstrated* in mice, using a resistor (as a source of heat for releasing drug and help dissolving the implant) and a power-receiving coil made of magnesium deposited onto a silk protein”pocket” that also protects the electronics and controls its dissolution time.
There have been other implantable medical devices, but they typically use non-degradable materials that have limited operational lifetimes and must eventually be removed or replaced — requiring more surgery.
The research was published online in the Proceedings of the National Academy of Sciences Early Edition the week of November 24–28, 2014. and was supported by the National Institutes of Health and the National Science Foundation.
* Devices were implanted in vivo in S. aureus-infected tissue and activated by a wireless transmitter for two sets of 10-minute heat treatments. Tissue collected from the mice 24 hours after treatment showed no sign of infection, and surrounding tissues were found to be normal. Devices completely dissolved after 15 days, and magnesium levels at the implant site and surrounding areas were comparable to levels typically found in the body. The researchers also conducted in vitro experiments in which similar remotely controlled devices released the antibiotic ampicillin to kill E. coli and S. aureus bacteria. The wireless activation of the devices was found to enhance antibiotic release without reducing antibiotic activity.