One tiny flick of a microscopic cellular hair, known as a cilium, can’t do much on its own. But together, these structures routinely pull off biological marvels within the body. Cilia remove inhaled pathogens from the respiratory tract, carry cerebrospinal fluid across brain cavities, transport eggs from the ovary to the uterus, and drain mucus from the middle ear to the nasal cavity.
The Cornell researchers vaulted that hurdle by taking inspiration from some things they learned in their earlier work. In August 2020 Guinness World Records recognized Cohen and his team for designing the world’s smallest walking robot, a machine that was just a fraction of a millimeter wide and could walk on four bendable legs. Much like those legs, the new artificial cilia are made of bendable, nanometer-thin film that can respond to electrical control.
Once the researchers had used these computer simulations to check out the theoretical aspects of what they were doing, they went on to produce a physical device. Their centimeter-wide chip is carpeted with about a thousand tiny platinum-titanium strips, divided into 16 ciliary units of 64 cilia each. Because each unit is independently connected to a computer control system, individual units can be separately programmed and then coordinated to move the test fluid in any given direction.