Paper towels that pack a punch against bacteria

Photo cour­tesy of Thinkstock.

Of the three ways we can dry our hands after scrub­bing down, the paper towel method tends to be the most hygienic. When I asked chem­ical engi­neering pro­fessor and chair Tom Web­ster how this could pos­sibly be, he told me that air dryers can actu­ally blow bac­teria onto other sur­faces, causing fur­ther con­t­a­m­i­na­tion down the line. So as we walk away all shim­mery and dry, bac­te­rial colonies begin to fester on the nearby sinks and paper towel racks we leave behind.

Nonethe­less, other exper­i­ments have shown that par­tic­i­pants actu­ally walk away with more bac­teria on their hands when they dry with paper towels than before they even washed up. You can imagine where this might become an issue in places like the doctor’s office, hos­pi­tals, and restaurants.

I went to the doctor the other day and they made me put on a dorky blue mask the second I told them I was get­ting over a cough. They do every­thing they can, but some things are cur­rently beyond control.

Paper towels col­lecting in waste bins can start to form so-​​called biofilms, or impen­e­trable coat­ings of bac­teria. For this reason, Web­ster decided to apply his work devel­oping anti-​​microbial med­ical devices to paper towels. He and his team coated paper towel frag­ments with nanopar­ti­cles of sele­nium, a non-​​metallic ele­ment. “We have seen that sele­nium inter­feres with pro­teins inside the bac­teria causing them to die,” said Web­ster, refer­ring to pre­vious work.

The coated paper towels man­aged to stave off 90 per­cent of bac­te­rial growth after 72 hours com­pared with uncoated towels, according to Webster’s recently pub­lished paper in the journal Journal of Nanomedicine.

Other researchers have attempted to design a sim­ilar product using things like silver nanopar­ti­cles, zinc oxide and even graphene, a single-​​atom-​​thick layer of carbon atoms pre­cisely arranged. But each of these also brought along prob­lems of expense and tox­i­city. The graphene towels caused 20 per­cent of mam­malian cells to die after just two hours. And, well, what is there to say about a silver-​​coated paper towel? Prob­ably some­thing having to do with princesses.

Webster’s team has esti­mated that the sele­nium towels wouldn’t cost any more than normal towers. In the case of med­ical devices like catheters, which they are also working on, the addi­tional costs are minor. And since mam­malian cells actu­ally need sele­nium to func­tion prop­erly, tox­i­city isn’t an issue. Finally, in that ongoing debate about antimi­cro­bial resis­tance, Web­ster assured me that sele­nium is likely not to become a cul­prit. “This is because sele­nium acts in a dif­ferent mech­a­nism than antibi­otics to kill bac­teria,” he explained.