Scientists have designed nanoagents that act like smart drug-delivery capsules—carrying an antibiotic deep into bacterial infection sites and releasing it only when activated by gentle ultrasound. Delivering antibiotics locally, directly to the site of an infection, is important, because treating the whole body with high doses increases the chances of bacteria developing resistance. Nanoagents can carry drugs straight to the infected area providing localized therapy with minimal amount of drug, reducing the risks of antibiotic resistance.