The traditional approach to defeating infectious bacteria has been chemical and biological, using antibiotics to beat some life-threatening microorganisms. Evolution is relentless, however, and we’re seeing more and more bacteria develop immunities to antibiotics quicker than we can develop new ones. 

Something bacteria are unlikely to adapt to, however, is a drill. 

A team from Rice University has developed a series of molecular mechanical drills to attack bacteria. What’s more amazing is that they seem to be working. 

Sometimes force is best

In the test stages, all six variants of the nano drills successfully punched holes in the membranes of each bacterium in under two minutes. This is potentially a game-changer because this physical attack is something that bacteria are unlikely to develop an adaptation to. 

“I tell students that when they are my age, antibiotic-resistant bacteria are going to make COVID look like a walk in the park,” says James Tour, professor of chemistry and of materials science and nanoengineering.

“Antibiotics won’t be able to keep 10 million people a year from dying of bacterial infections. But this really stops them.”

At first, Tour and his team were powering these molecular drills with UV light, which they knew could be too harmful to humans. The team’s newest model is powered by still-blueish light at 405 nanometers, spinning the molecules’ rotors at 2 to 3 million times per second. Additionally, the light at the wavelength has its own mild antibacterial properties. 

Cleaning up straggler bacteria

The nano drills are based on the work of Nobel Prize winner Bernard Feringa, which Tour and his team furthered. The lab’s first test was successful on an open burn wound, and even killed methicillin-resistant Staphylococcus aureus, a common cause of skin and soft tissue infections that killed more than 100,000 people in 2019.

While antibiotics can go a long way toward killing off harmful bacteria, some very tough and persistent ones can evade medication. That’s where the drills come in. 

“Even if an antibiotic kills most of a colony, there are often a few persister cells that for some reason don’t die,” Tour says. “But that doesn’t matter to the drills.”

Now Tour and his team are working to refine their nano drills to ensure that they don’t damage human and mammal tissue. 

Source Study: Science Advances — Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane (science.org)