Microfluidic Pump Powered by Self-Organizing Bacteria

Results are presented that demonstrate the successful use of live bacteria as mechanical actuators in microfabricated fluid systems. The flow deposition of bacteria is used to create a motile bacterial carpet that can generate local fluid motion inside a microfabricated system. By tracking the motion of tracer particles, we demonstrate that the bacterial cells that comprise the carpet self‐organize, generating a collective fluid motion that can pump fluid autonomously through a microfabricated channel at speeds as high as 25 µm s−1. The pumping performance of the system can also be augmented by changing the chemical environment. The addition of glucose to the working buffer raises the metabolic activity of the bacterial carpet, resulting in increased pumping performance. The performance of the bacterial pump is also shown to be strongly influenced by the global geometry of the pump, with narrower channels achieving a higher pumping velocity with a faster rise time. Biological organisms as mechanical actuators: Active surfaces are formed in engineered microfluidic networks, and biologically powered pumping systems are demonstrated. The performance of these devices, powered by bacterial carpets (see figure), is sensitive to both local environment and device geometry. The rise of the pumping rate (maximum of 25 μm s−1) is due to a self‐organized global coordination amongst the flagella that form the bacterial carpet.