Germ Killer App

By Zhuo “George” Tan
ISE Ph.D. Student

The latest weapon against infection could be your phone

There are over a million joint replacement surgeries performed each year in the United States alone. As with any surgery, one of the major concerns afterwards is infection. Now imagine if patients could use their smartphones to release an army of germ-killers from inside their own bodies to combat any infection. This may sound like science fiction, but ISE researchers are working to make it a reality.

The high cost of treating infections and the resistance to antibiotics have pushed researchers to find a better way to fight surgical infections. So for the last four years, I have been working with Professor Rohan Shirwaiker on a system to do just that. We have been experimenting by applying a low intensity electrical charge to a thin film made of silver. This charge causes the release of silver ions from the surface of the film. These ions have an amazing germ-killing property and low toxicity which makes them ideal for fighting infections within the body.

We place the thin silver film at one end of the titanium implanted device. Then we add a power source, in this case a watch battery, inside the implant. The body’s own fluids will complete the circuit between film and battery. As an added benefit, the low intensity electrical stimulation can enhance bone formation. This will help the bone attach faster to the implant.

I am excited to report that our tests show a 99.9% decrease in bacteria after 24 hours and the area was infection-free after 48 hours. Our next step is to switch from direct current to alternating current so that we can increase the effectiveness of the silver by preventing it from oxidizing. In the future, we want to use a cellphone to control the release of the silver ions and add medical sensors to track and analyze the area around the implant in real time.