Chemical drugs are great for killing bacteria, but with antibiotic resistance on the rise we need new methods. Particularly promising are mechanical solutions like Rice University’s “nanodrills,” which bore into cell walls. Now, the team has shown that the devices work against larger organisms like worms and water fleas.

The nanodrills are essentially tiny rotors that, when activated by light, spin at speeds of up to 3 million times per second. That lets them burrow into cells, either killing the target outright or making it easier for other methods, like drugs, to do the job. Just a few months ago the Rice team demonstrated them on cancer cells and antibiotic-resistant bacteria, and now they’ve moved onto bigger targets.

Those previous tests were done in lab dishes of cells, but for the new study the researchers tried out the nanodrills in living creatures – a worm species called C. elegans, and a type of plankton called Daphnia.

The nanodrills caused the worms’ skin to lose pigment, killing about 70 percent of them over the next few days. In the plankton, meanwhile, the drills cut off many of their external limbs, also killing the majority of them.

C. elegans worms, before and after exposure to the nanodrills (white areas indicate damage) Thushara Galbadage/Biola University

“The work here shows that whole organisms, such as small worms and water fleas, can be killed by nanomachines that drill into them,” says James Tour, lead researcher on the study. “This is not just single-cell death, but whole organism, with cell death in the millions.”

In the next test, the researchers moved up to a larger animal – mice. They applied a topical mixture containing the tiny machines to the skin of mice, and once activated the drills caused lesions and ulcers to appear.

While that doesn’t sound very nice to the poor animals, the researchers say that this test shows how the nanodrills could eventually be used for good. They could be applied to human skin to drill into melanomas, kill parasites like worms, or fight off eczema and other skin diseases.

The idea is that the drills can be “trained” to only target certain cells, so they won’t harm healthy human cells nearby.

The research was published in the journal ACS Applied Materials & Interfaces.

Source: Rice University