“The iPhone is great, but what if I wanted to put it in my brain?” John A Rogers from the University of Illinois asked this question at a recent talk about electronics that work inside our bodies. From stretchy electronic devices on the surface of our skin to implanted devices that “talk” to our smartphones; the future of medicine could be getting under your skin.
We are now able to produce silicone circuits which are as flexible as a rubber band and as thin as a temporary tattoo. This means that devices can be stuck on to our skin and left to measure signs of ill health such as temperature, hydration and heartbeat. These devices are particularly useful in neonatal care. But scientists are now taking this technology even further…
Electronic devices that are safe enough to be implanted inside our bodies and simply dissolve away when they’ve done their job are becoming a reality. They are made from silicone and magnesium, which exist naturally in small concentrations inside the body and are safe enough to be implanted. The innovation that makes these dissolvable devices possible is the development of tiny silicone membranes with imprinted magnesium circuitry. These membranes can be less than 100 millionth of a meter thick and dissolve easily in the slightly alkali conditions of our blood. Scientists can control the amount of time these devices stick around inside the body by wrapping them in a thin layer of silk protein.
Silk is non-harmful and dissolvable, so makes an ideal covering material. Silk fibres (from silk worms) are broken down by boiling in salt water to create a kind of liquid silk that is then used to coat the devices. By altering the processing of the silk protein, it is possible to control how long it will take to dissolve in the body, hence controlling how long the device will last.
The first gadgets to be produced in this way simply heat up; these can be implanted into wounds or at the site of a bone fracture during surgery. Raising the temperature by just a few degrees at the site of a wound can be enough to kill bacteria and ensure the area remains sterile. Scientists have also made devices that can measure electrical activity within the brain, though so far these have only been tested in animals. The future of this disappearing technology is very exciting, for instance in allowing controlled drug delivery in a particular location.
Another new technology being developed in the world of medical electronics involves wireless communication from inside the body. Scientists have produced a wireless implant that can predict a heart attack. This small chip can be implanted under the skin to detect various substances circulating in the bloodstream, including a molecule called troponin. This is released by heart muscle when it is under the extreme strain that precedes a heart attack. The implant has a radio transmitter that sends signals to a patch outside the body. This can then transmit data to a smartphone via Bluetooth. The chip is currently being trialled in patients in intensive care, but in the future could be used by those who are at high risk of heart problems. In the future, chips like this one could also be used to detect other metabolites in the body, so could prove useful for monitoring a wide range of conditions. For instance, in diabetes accurate and simple monitoring of blood glucose could be extremely useful. The application of Bluetooth to medical devices that operate from inside the body could prove to be a significant step forward in the monitoring of a number of serious conditions.
The future of biomedical devices is looking positive; the application of developments in physics and materials sciences to medical problems is very exciting. From the prevention of infection to predicting a heart attack these devices are likely to save many lives.
Post by: Claire Scofield