Researchers at the Massachusetts Institute of Technology and Harvard University have integrated live bacteria into 3D-printed objects to make them more dynamic. The underlying resin material is embedded with a chemical “instruction” that indicates that the microbial layer emits a specific color of fluorescence, resulting in stunning patterns and design arrays. Scientists call their creations mixed biological materials (HLM), which are made from unusual ingredients.
Starting with two resins commonly used in 3D printing, most objects are made of solid materials that provide structures. Some slices are made from another temporary resin, which can be overhanged and then dissolved when it is no longer needed.
The team realized that the resin material was absorbent, so they were able to fill it with specific chemicals after printing. The last layer is a hydrogel injected with engineered E. coli, spraying it onto the final object. After a few hours, the microorganisms begin to glow in different colors in areas made of absorbent resin. Because this activates certain genetic reactions in bacteria, which cause scoffs. By exchanging different chemicals, microorganisms and resin structures, objects can be programmed to glow in different patterns and colors.
To verify the concept, the team made small disks and larger masks, all of which formed interesting colors and patterns after a few hours as bacterial colonies expanded and chemical signals responded.
In the future, the team says, the technology could be used to make biomedical devices, smart packaging to detect bacterial contamination and other surfaces that react to the environment.
The study was published in the journal Advanced Functional Materials.