MIT Engineers Create 'Smart' Self-Assembling Materials by Using E. Coli

MIT engineers have combined animate and inanimate ingredients to create self-assembling or "self-healing" materials.

According to Daily Tech, MIT scientists combined E.coli bacteria with gold nanoparticles to make hybrid materials that are functional and contain living cells.

The hybrid materials were created to make cells communicate with each other so they can change the materials's composition over time.

They also wanted to imitate natural processes, such as the way bone generates material in response to environmental stimuli.

E. coli was chosen because it has biofilms, which have sticky amyloid proteins called curli fibers that glue bacteria to other proteins in the body. The fibers allow other cells to stick to the E. Coli and become attached.

A significant aspect of the process are extracellular CsgA protein, which are found in curli fibers and can self-assemble. When peptides are added, CsgA can be altered to collect and self-assemble other materials. The process allows engineers to wield it with "trigger" molecules.

The E. coli then produces CsgA, which contains peptides made up of the amino acid histidine when a certain molecule is present. Histidine particles then cling to gold nanoparticles, and the gold forms a "network" because of the self-assembly of the amino acid particles.

That makes the E.coli conductive. Any number of peptides can be used to manipulate the living cell.

The combination of the living and non-livng materials can create "smart" materials, like self-assembling batteries, solar cells and medical diagnostic sensors.

"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," said Timothy Lu, the primary author of the study.