Nano Implantable Electronics

In recent years, implantable electronics have started to interface with wearable and pervasive networks. The main application of this technology has been focused on healthcare monitoring. For examples, a flexible data-logger patch with sleep-analysis software can be used to detect sleep disorders of patients. In principle, a patient places the patch on his or her forehead to record up to nine hours of EEG (electroencephalogram) and head movement when sleeping. The patch itself integrates all the electronics (electrodes, accelerometer, amplifiers, and so forth), batteries, and up to 36 Mbytes of memory in a flexible package. When the user places the patch on its base, capacitive coupling reads the logged data and inductive coupling recharges the batteries. The data can be transmitted to computer via wireless and analyzed with software in order to diagnose the sleep disorders.

Wireless ECG Patch (Figure from http://medgadget.com/archives/2007/10/)

One of challenges for this technology is to implantation under the skin. Implanted electronics could provide a clearer picture of what's going on inside the body to help monitor chronic diseases or progress after surgery, but biocompatibility issues restrict their use. Many materials commonly used in electronics cause immune reactions when implanted. And in most cases today's implantable devices must be surgically replaced or removed at some point, so it's only worth using an implant for critical devices such as pacemakers. Prof. Fiorenzo Omenetto from Tufts University has demonstrated the use of silk substrates fitted with ultra-thin silicon transistors that can be implanted to conform to the body's tissues, opening the door for enhanced implantable medical devices of various uses.

Nano Implantable Electronics under the skin, an array of light-emitting diodes could signal the concentration in the blood of biomarkers such as insulin. (Figure from http://www.technologyreview.com/biomedicine/25086/)

He and co-workers has used silk films to hold in place arrays of tiny silicon transistors and LEDs--a possible basis for implantable devices that will help identify the concentration of disease markers. The researchers have shown that the devices function fine in small animals, with no evidence of scarring or immune response. The silk dissolves, leaving behind a small amount of silicon and other materials used in the circuits. The video that shows development of an implantable electronics is presented below.

Nano Implantable Electronics is one of ten emerging technologies 2010 published by MIT Review.