Painting with light-powered bacteria
Researchers use genetically modified bacteria to produce light-induced patterns as a potential route for engineering smart materials.
Micro- and nano-fabrication can revolutionise many areas of technology, including personalised medicine. There are two conceptually distinct ways to construct such structures: ‘top-down’ techniques such as lithography use ‘scalpels’, while in ‘bottom-up’ techniques, microscopic ‘Lego components’ move themselves into position and self-assemble. The University of Edinburgh team demonstrated a novel method whereby arbitrary patterns can be assembled in a fluid environment and reconfigured in real time using light-controlled motile bacteria as the ‘Lego’ blocks.
The researchers demonstrated this method by constructing a bespoke mutant of Escherichia coli bacteria and used it to assemble the initials of the University of Edinburgh as well as a smiley face.
The method is shown to be programmable, that is the self-assembled patterns can be switched in real time. The physics and biology controlling the rapidity of switching and the sharpness of the patterns is investigated in detail, allowing the team to ‘tune’ the pattern formation.
This protocol provides a new paradigm for self-assembly of structures on a scale (10-100μm) which presents difficulties for many if not all current fabrication methods. At the same time, this methodology has significant implications for the burgeoning field of ‘active matter’ science.