Two students from Hong Kong recently took second place at the Intel International Science and Engineering Fair in the materials science category for an invention that's pretty remarkable. The teenagers developed a door handle that is self-sanitizing, killing germs that are spread by hand contact.
As we all know, door handles and other heavily-touched surfaces like elevator buttons, stair railings and subway polls, can be ground zero for the spread of viruses like colds and flus. An infected person may cough or sneeze in their hand, then touch the surface and the next person to touch it ends up with the germs on their hand as well. All it takes is one eye rub or touch of their mouth and they're infected too.
Regular hand-washing is the key to protecting oneself from getting sick, but even fewer bugs may spread around if they're stopped at the point of contact. This could be especially helpful when it comes to the flu, which can have serious complications in the very young and old.
That's the premise behind the germ-killing door handle invented by Sum Ming Wong and Kin Pong Li. The students brainstormed minerals that were toxic to germs and settled on titanium dioxide, which they used to coat a glass tube. Since titanium dioxide requires UV light to kill germs, they then placed an LED in one end to provide UV light and then put brackets on either side which allow it to affix to a door as a handle.
Since the handle requires an LED, that means it needs a source of electricity to keep it shining. The students fashioned a gear box that allows for capturing energy from the door opening and closing. The energy is stored in a battery that continually feeds power to the door handle.
In tests the door handle coating was 99.8 percent effective at killing germs applied to its surface. A version of this technology could one day be placed on doctor's office doors, grocery cart handles and any other surfaces that get an extra share of hand contact.