Imagine a world where nonliving devices and building materials had some of the same advantages as living things, such as the ability to self-heal. Well, scientists at the Massachusetts Institute of Technology are working to make that vision a reality. They have coaxed bacterial cells to produce biofilms that incorporate nonliving materials, essentially creating "living materials" that can be integrated into everyday objects and devices, from solar panels to adjustable furniture, reports MIT News.
The research was inspired by organic materials like bone, which is super strong despite being light and shot through with holes. Bone manages this engineering feat because its cells incorporate hard minerals like calcium into the structure of the living tissue.
"Our idea is to put the living and the nonliving worlds together to make hybrid materials that have living cells in them and are functional," said Timothy Lu, an assistant professor of electrical engineering and biological engineering. "It’s an interesting way of thinking about materials synthesis, which is very different from what people do now, which is usually a top-down approach."
Lu and colleagues chose to use the bacterium E. coli, a common intestinal organism, for the research because it naturally produces biofilms that contain so-called "curli fibers," which are amyloid proteins that attach to surfaces. The fibers were modified by adding peptides that can capture select nonliving materials. In this case, the researchers chose peptides that could capture gold nanoparticles and quantum dots.
Researchers then programmed the E. coli cells to produce biofilms with the conducting properties of gold nanowires. Other films were studded with quantum dots, or tiny crystals that exhibit quantum mechanical properties. The cells were further able to communicate with each other, thus having the ability to change the composition of their biofilms over time.
"It’s a really simple system but what happens over time is you get curli that’s increasingly labeled by gold particles. It shows that indeed you can make cells that talk to each other and they can change the composition of the material over time," Lu said. "Ultimately, we hope to emulate how natural systems, like bone, form. No one tells bone what to do, but it generates a material in response to environmental signals."
The technology could have multifarious applications, such as with energy technology. Improved batteries and solar cells could be produced, and biofilms with enzymes that catalyze the breakdown of cellulose could be used for the conversion of agricultural waste into biofuels. The possibilities are endless — furniture could even be built out of these "living materials." Devices constructed from these materials could adjust to their environments in ways that traditional nonliving materials cannot.
"I think this is really fantastic work that represents a great integration of synthetic biology and materials engineering," said Lingchong You, an associate professor of biomedical engineering at Duke University.
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