Posted by: Prospector PJ5 FEB 2014
Tiny biocompatible electronic devices could soon be available to implant for pain relief or tackle infection for a specific period before dissolving completely. These “transient electronics” can generate localised heat to fight infection or stimulate nerve endings to reduce pain. They do not require risky surgical procedures for removal after performing their role.
Research into transient electronics presented at a meeting of the American Chemical Society last year demonstrated how the electronics are enclosed in a material that dissolves when exposed to water or body fluids, and the number of layers of material determines how long the device lasts. Once the encapsulating layer has dissolved, the electronic connections take about 30 minutes to dissolve and the device stops working.
These “born to die” electronics are silicon-based, like conventional circuitry, but dissolve because they are extremely thin. Silicon dissolves in the body at about 1nanometre per second, so that a standard integrated circuit wafer would take about 1,000 years to dissolve. But a silicon chip just 20 nanometres thick can disappear in two weeks. The chip is covered in magnesium oxide, along with an outer jacket of silk.
The devices can be powered without an external electricity source by incorporating “piezoelectric” zinc oxide, which can produce electricity when bent or twisted. This could be achieved by movement of muscles, pulsing of blood vessels or beating of the heart.
Other potential medical uses include pacemakers, temperature monitors and drug delivery systems. Non-medical applications include mobile phones that would stop working when it was time to upgrade to a new model, thereby reducing the volume of e-waste, and water quality sensors that would not need retrieving and would not damage the environment.
Potential military applications include reducing the amount of surgery and risk of infection at field hospitals, and electronic “eyes and ears” that could be deployed in enemy territory and set to dissolve when their mission is over.