Optimizing health, measuring progression of age-related change in metabolism, and detecting disease are far more challenging today than they will be in the future. We can envisage sophisticated implanted devices that cheaply and continuously measure aspects of our biology that are presently expensive to test - and the first steps in the development of such implanted monitors are already underway. "Michael Cima and his team developed an implantable sensor that uses antibodies attached to nanoparticles to detect cancer related biomarkers. In 2009 Cima showed that he could implant these devices into human tumors in mice and then 'read' the cancer growth using MRI. No biopsies need. Over the past few years, Cima and his team have adapted their work to create a very similar device that measures biomarkers related to heart damage. ... This work is very exciting, but still very early in development. As we've said many times before, successes with mice experiments and successes with human experiments can be miles apart. The 5mm cylindrical cancer implant and the 8mm heart monitoring disk both need more time to be perfected. The antibodies used to detect biomarkers have a limited lifetime in the body. Currently an implant probably wouldn't last much longer than two months. ... If MIT continues to see good results with these early prototypes, there's a good chance we'll see similar devices in clinical trials in the near future. Cima thinks that such experiments could be as little as five years away. The lowest hanging fruit are implants that could monitor for pH levels - acidity is often a hallmark of cancer cells. After that, we may see versions that can accurately detect hormone levels and drug responses."