Interestingly, these look very similar in design to so-called bacterial ratchets (see Fig 7 of [1]) which allow swimming bacteria to be sorted by size or swimmi

Interestingly, these look very similar in design to so-called bacterial ratchets (see Fig 7 of [1]) which allow swimming bacteria to be sorted by size or swimming speed etc. People have even used these ideas to create tiny bacteria-powered motors [2]. [1] https://arxiv.org/abs/1604.01072 https://arxiv.org/abs/1604.01072 [2] http://physicsworld.com/cws/article/news/2009/oct/23/bacteria-power-micro-ratchet http://physicsworld.com/cws/article/news/2009/oct/23/bacteri...