SMALL WONDER

How will nanomachines change our lives?

- DHRUV KHULLAR

Scientists in Texas have created "molecular machines" that drill into bacteria.

Ana Santos, a microbiologist at Rice University, grew up in Cantanhede, a small city in Portugal that is known as a biotechnology hub and a source of good wine. When she was a child, her grandfather, who bound books for a living, was an energetic man who often rode his bicycle around town. But by 2019, his health had deteriorated and he depended on a catheter. One day, he spiked a fever; doctors found that his urinary tract was infected with a highly drug-resistant form of Klebsiella pneumoniae, a bacteria that is commonly found in the gut. None of their antibiotics could treat it. A few days later, he died. “There was literally nothing they could do for him,” Santos told me recently, fury in her voice. “A simple bacterial infection kills him? I thought medicine had dealt with that.”

At the time, Santos was at the Centre for Interdisciplinary Research in Paris, studying genes that allow some bacteria to live longer than others. But after her grandfather’s death she decided to focus instead on new ways of killing pathogens. One problem with traditional antibiotics is that bacteria, which are always evolving, can develop resistance over time. To stay competitive in the arms race between bacteria and biotechnology, Santos reasoned, scientists might need entirely new weapons. She read in Nature that scientists at Rice, led by the chemist James Tour, had developed “molecular machines” that spun like microscopic drills and were roughly ten thousand times smaller than the width of a human hair—small enough to puncture and kill individual cells. Shortly thereafter, Santos moved to Houston to join Tour’s lab.