Most bacteria on Earth live in communities known as biofilms such as plaque on teeth or the bacterial infection of catheters. Although these bacterial communities are pervasive and of significant scientific interest, there is still much we don’t know about biofilms.
A desire to learn more is part of the inspiration behind a new technique, developed in the Stanford lab of Ingmar Riedel-Kruse, PhD, assistant professor of bioengineering, that aids scientists in shaping their growth.
The technique, published in the Proceedings of the National Academy of Sciences, is called biofilm lithography because it is similar to lithography used to make electronic circuits. To make the patterns, the researchers created genetically engineered E. coli, a type of bacteria, that secretes a sticky protein in response to a particular wavelength of blue light. If they shine a pattern rendered in that light on a culture dish of these modified bacteria, they will grow into a biofilm that matches that pattern.
Compared to other biofilm patterning techniques, biofilm lithography has the benefit of speed, simplicity, higher resolution and compatibility with a variety of surface environments including closed microfluidic devices, the researchers said. Given these advantages, the researchers hope it can support a wide-range of research.
“We're hoping this tool can be applied toward further understanding bacterial communities, both natural and synthetic,” said Xiaofan Jin, a graduate student in bioengineering and lead author of the paper in a Stanford news story. “We also see potential in having these communities do useful things, such as metabolic biosynthesis or distributed biocomputation. It may even be possible to create novel biomaterials such as conductive biofilm circuits.”
In initial tests, the biofilm remained stable for three days after the light was removed.
The researchers are currently taking steps to grow multi-species communities with biofilm lithography. In particular, they hope to understand how bacteria in a biofilm may share antibiotic resistance.
Image of a biofilm design by Xiaofan Jin and Ingmar Riedel-Kruse