Michael McAlpine: biointerfaced nanodevices
The McAlpine lab has developed a basic platform for sensing medically relevant information that they're now refining. They created a robust, wireless circuit chip that can withstand daily wear and harsh chemicals. This chip can tell when there are any bacteria or other cells on it. When applied to a surface, it can be alert you to any contaminants. The lab took inspiration from children's temporary tattoos and developed a mechanism for easily applying the chip to biological surfaces. Using raw silk, they produce a flexible, gel-like surface that they can print the chip on. When the silk gets wet, it becomes sticky and dissolves. If you do this while you're pressing the chip onto a biological surface, it will transfer off the silk and stick to that surface. By virtue of the materials and design, the chip can discern the presence of a single cell, which is extraordinarily useful in the medical world. Moreover, it's wireless, so that information can be remotely monitored.
Currently, the lab is looking at uses for the chip on skin, teeth, medical supplies, and eventually other biological surfaces. On teeth, it could be used to detect the presence of bacteria that cause mouth or digestive tract infections. In lab tests they were able to detect H. pylori, a bacteria that (in conjunction with a few other factors) causes stomach ulcers, in saliva. If you can constantly monitor your saliva for H. pylori, you can get treatment for it before you actually get an ulcer. Similarly, medical equipment needs to be sterile so that it doesn't bring any infections to patients. Having such a sensitive and quick monitoring system would allow medical care providers to avoid just that situation. It would improve upon the current procedure for testing food & water for pathogens, in which scientists culture a sample of the food or water to see if a known pathogen grows. Since the pathogen has to grow for this method, it can take days or weeks. The graphene chip is instant because it's a direct, electronic measurement of the chip in real time.
The McAlpine lab's work into harvesting biological energy to power devices is just as intriguing. One of their major long-term projects in this area is developing a device that can harvest the mechanical energy of breathing to power a pacemaker. When you breathe, your lungs expand and stretch. We power this action through the energy we get from food. If you have a device that can sit on top of this surface and then make its own energy from that physical movement, it wouldn't need external power. That's a problem in modern pacemakers, which use chemical batteries and need to be replaced (through open chest surgery) every five or so years. Ideally, such a device would be able to provide the pacemaker all the energy it needs just from that lung movement. Only one surgery would every be necessary, since there wouldn't be any energy source to replace. This is theoretically possible, since the mechanical energy of the lungs during breathing is more than what a pacemaker uses. It's just a question of developing the right device.
As amazing as this technology is, it's still in its early stages. The ideas are there, but not all of the problems have been solved to make it entirely practical. One of the biggest issues I see is that the sensory chip isn't very selective. Right now, the lab has been able to produce graphene strips that only respond to bacteria, but ideally you would want it to be able to detect single species, or at least a single group of species that causes one disease. Having the chip respond selectively to bacteria is already a huge step, since that means it would be able to ignore things like your own cells. However, there's still a lot more refinement to be done (and they are working on it!).
(External sources: McAlpine Research Group)
