Researchers at MIT, Harvard University and Dana-Farber Cancer Institute in the US developed a method for 3D printing objects that can control living organisms in a predictable way.

Called hybrid living materials, the team precisely incorporated various chemicals into the 3D printing process. The chemicals act as signals to activate certain responses n biologically engineered microbes that are spray-coated onto the object. Once added, the microbes display specific colours or fluorescence in response to chemical signals.

The aim of the study is to make a design tool for producing objects and devises incorporating living biological elements that are predictable and scalable.

To make the hybrid living materials, the researchers used a commercially available multimaterial inkjet based 3D printer. They developed customised recipes for the combination of resins and chemicals used for printing. Finally, a living layer, consisting of a surface coating of hydrogel, infused with biologically engineered bacteria, is spray-coated onto the object.

The multiresin 3D printing platform can use anywhere from three to seven different resins with different properties, mixed in any proportions. In combination with synthetic biological engineering, this makes it possible to design objects with biological surfaces that can be programmed to respond in specific ways to particular stimuli such as light or temperature or chemical signals.

The printing platform the team used allows the material properties of the printed object to be varied precisely and continuously between different parts of the structure, with some sections stiffer and others more flexible, and some more absorbent and others liquid-repellent. Such variations could be useful in the design of biomedical devices that can provide strength and support while also being soft and pliable to provide comfort in places where they are in contact with the body.

In the study, the researchers produced masks with incorporated bacteria, to show the material’s potential for biomedical devices. The technology could also be used for smart packaging, which detects contamination, or even environmentally responsive architectural skins that can respond and adapt in real time.

Photo: MIT