MIT researchers have turned colonies of Pantoea agglomerans bacteria into working transistors, printed them onto agar plates, and wired 24 colonies together to build a circuit that adds two input signals. The work appears in Nature Chemical Biology.
The team, led by Christopher Voigt and postdoc Hamid Doosthosseini, did not try to cram an entire circuit inside a single cell. Instead they engineered two types of bacterial transistors that switch on or off using a molecule called OC-6, then detect a target molecule, OC-12, and output OHC-14. Three relay strains translate that output into a signal the next transistor can read. Colonies spaced five millimeters apart on agar ensure information flows in one direction only.
A 24-colony circuit takes roughly eight hours to finish a calculation. That is glacial compared to silicon. But the point is not to replace your laptop. Voigt says the goal is to embed computation into living systems, like plant roots that detect drought and synthesize a fungicide overnight. The concept of substrate-independent computation has long suggested that biology could run logic in ways electronics cannot, and these bacterial transistors are an early proof that cells can serve as programmable hardware rather than mere sensors.