A new dialyzer (an apparatus to clean the blood) inspired by the snap-action mechanism of the Venus fly trap is presented in Nature Communications this week. The material is made of nanometre-thick wires whose tips coil up when bacteria touch them, thereby forming claws that can hold the pathogens tightly.

When antibiotics fail, actively cleaning a patient’s blood is an alternative option to get rid of an infection. In that process, physicians remove patients’ blood from the body through a needle in one arm, pass it through a cleansing device and then transfer it back to the patient through a needle in the other arm. However, the speed of the bloodstream makes it hard for the cleansing material to hold on to the captured bacteria and they can get flushed back into the blood.

Tie Wang and colleagues developed a foam, spiked with fine hairs, which can be used as a cleanser. The tip of each hair has a detecting element that recognizes bacteria. When in contact with a bacterium, the hair end quickly rolls up, thereby capturing the bacteria and protecting it from the force of the bloodstream.

The authors note that clinical studies are required to evaluate the effectiveness and safety of this new material in general healthcare.