An interdisciplinary team from MIT, Harvard and the Dana-Farber Cancer Institute has developed a unique approach for 3D printing objects that can not only contain living organisms, but also control them. The process, which relies on multi-material inkjet printing, could be used to produce 3D printed biomedical devices, like braces, with built-in therapeutic compounds derived from living cells.
The project, led by the MIT Media Lab’s Neri Oxman, is known as hybrid living materials (HLMs) and is achieved by combining adapted 3D printed materials with biologically engineered microbes, which are coated onto the printed part’s surface. As can be seen in the photos, the reaction between the microbes and the 3D printed part’s chemical composition creates a colorful, fluorescent effect.
The process developed by the interdisciplinary team consists of several parts. One of the most important steps was developing an inkjet 3D printing resin that would allow for the living organisms to survive and grow. As the research team explains, it found that a combination of a dissolvable support resin and structural resin provided the necessary absorbency. This enabled it to integrate chemical signals into the material, which function to control the living organisms.
The next phase in creating HLMs is to apply a hydrogel infused with biologically engineered bacteria to the printed object using a spray-coating technique. The chemicals in the 3D printed part function as signals and activate responses in the engineered microbes. This reaction results in a colorful effect. According to the researchers, the colors can take several hours to develop—while the bacteria grows—but eventually become stable.
“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,” explained Rachel Soo Hoo Smith, a graduate student from the MIT Media Lab.
The team used the method to create a series of test shapes, including coin-shaped discs and face masks which were coated with genetically modified E. coli bacteria. Ultimately, the research team—which includes specialists in biology, bioengineering and computer science—hopes to create a scalable and “robust design tool for producing objects and devices incorporating living biological elements.”
“There are exciting practical applications with this approach, since designers are now able to control and pattern the growth of living systems through a computational algorithm,” said Oxman, Associate Professor at the MIT Media Lab. “Combining computational design, additive manufacturing, and synthetic biology, the HLM platform points toward the far-reaching impact these technologies may have across seemingly disparate fields, ‘enlivening’ design and the object space.”
The unique approach devised by the MIT-led team can create many types of biomedical tools. And, because of the inkjet printer’s multi-material capability, they can even have tunable properties, like varying stiffnesses and absorbencies.
“In the future, the pigments included in the masks can be replaced with useful chemical substances for human augmentation such as vitamins, antibodies or antimicrobial drugs,” Oxman added. “Imagine, for example, a wearable interface designed to guide ad-hoc antibiotic formation customized to fit the genetic makeup of its user. Or, consider smart packaging that can detect contamination, or environmentally responsive architectural skins that can respond and adapt—in real-time—to environmental cues.”
The hybrid living material research was recently published in the journal Advanced Functional Materials.