MIT and Harvard 3D print colorful masks using programmable microbes
Researchers at MIT and Harvard have incorporated living microbes into 3D-printed objects to make them more dynamic. The underlying resin material is embedded with chemical “instructions” that tell a layer of microbes to fluoresce in particular colors, producing a stunning array of patterns and designs.
The scientists call their creation hybrid living materials (HLMs), and they’re made with a few unusual ingredients. They start with two types of resin commonly used in 3D printing – the bulk of the object is made of a solid material that provides structure. Some sections were made using another type of resin that’s normally meant to be temporary, supporting overhanging sections before dissolving away when it’s no longer needed.
The team realized that this secondary resin material was absorbent, so they were able to fill it with specific chemicals after printing. The final layer is a hydrogel infused with engineered E. coli, which is sprayed onto the finished object. After a few hours, the microbes begin to glow in different colors, localized over the areas made with absorbent resin.
The reason for this is that the chemicals in those sections are specifically chosen because they activate certain genetic responses in the bacteria, making them fluoresce. By swapping out different chemicals, microbes and resin structures, objects can essentially be programmed to glow in different patterns and colors.
“We can define very specific shapes and distributions of the hybrid living materials and the biosynthesized products, whether they be colors or therapeutic agents, within the printed shapes,” says Rachel Soo Hoo Smith, co-lead author of the study.
For the proof of concept, the team made small disks, as well as larger face masks, all of which grew intriguing colors and patterns after a few hours, as the bacterial colonies expanded and reacted to the chemical signals.
The team says that in future, this technique could be put to work to make biomedical devices, smart packaging that detects bacterial contamination, and other surfaces that respond to environmental cues.
The research was published in the journal Advanced Functional Materials. The team describes the work in the video below.