Engineering Collective Behaviors

Much of the world consists of many small things, animate or inanimate, interacting with each other to produce something larger than, and different from themselves. Comprising murders of crows, armies of ants, schools of fish, dunes of sand, and various organs in your body, the collective behaviors of these systems embody a different approach to engineering than we currently employ. This thesis explores three examples where principles from collective behaviors are deployed as engineering tools. The first example presents how the collective phenomenon of ‘percolation’ can be leveraged to rapidly produce a low-cost, best-in-class strain gauge (100% strain with a linear output and gauge factor of 1) using collectives of carbon nanotubes. The second example discusses how a modified inkjet printer can be used to simulate morphogenetic inputs and thereby manipulate the spatiotemporal patterns of gene expression in bacterial colonies. The final example explores control of collective motion (canonical ‘swarming’) through the use of bioelectric cues to herd epithelial cells in a manner analogous to how a sheepdog herds sheep.