Researchers at the University of Campinas's Chemistry Institute (IQ-UNICAMP) in the state of São Paulo, Brazil, have developed a template-free technique to fabricate cilia of different sizes that mimic biological functions and have multiple applications, from directing fluids in microchannels to loading material into a cell, for example. The highly flexible cilia are based on polymer-coated iron oxide nanoparticles, and their motion can be controlled by a magnet.