The MIT research team started working on the implantable chip in the mid-1990s. John Santini, then a University of Michigan undergraduate visiting MIT, took it on as a summer project under the direction of Cima and Langer. Santini, who later returned to MIT as a graduate student to continue the project, is also an author of the new paper.
In 1999, the MIT team published its initial findings in Nature, and MicroCHIPS was founded and licensed the microchip technology from MIT. The company refined the chips, including adding a hermetic seal and a release system that works reliably in living tissue. Teriparatide is a polypeptide and therefore much less chemically stable than small-molecule drugs, so sealing it hermetically to preserve it was an important achievement, Langer says.
The human clinical trial began in Denmark in January 2011. Chips were implanted during a 30-minute procedure at a doctor's office using local anesthetic, and remained in the patients for four months. The implants proved safe, and patients reported they often forgot they even had the implant, Cima says.
Chips used in the study stored 20 doses of teriparatide, individually sealed in tiny reservoirs about the size of a pinprick. The reservoirs are capped with a thin layer of platinum and titanium that melts when a small electrical current is applied, releasing the drug inside. MicroCHIPS is now working on developing implants that can carry hundreds of drug doses per chip.
Because the chips are programmable, dosages can be scheduled in advance or triggered remotely by radio communication over a special frequency called Medical Implant Communication Service (MICS). Current versions work over a distance of a few inches, but researchers plan to extend that range.
In the Science Translational Medicine study, the researchers measured bone formation in osteop
|Contact: Kimberly Allen|
Massachusetts Institute of Technology