The Cutting Edge of 3D Printing: Chemicals Within Chemicals, and Printing Tissue In Bodies

Engineers at the University of California, Davis, have developed a new approach to 3D printing with potential applications in tissue engineering, soft robotics, and wearable technology — by repurposing the glass capillary microfluidic devices used in their lab to encapsulate one chemical inside droplets of another: The resulting structure looks like a Pac-Man maze, with little dots of PEGDA droplets surrounded by PDMS. Once the PEGDA diffuses out of the droplets, it chemically softens the PDMS, making the structure more flexible. "You can also encapsulate other chemicals in the droplets to make the overall matrix much softer or harder," said Jiandi Wan, assistant professor of chemical engineering at UC Davis. The team also showed that droplet-based 3D printing can be used to produce flexible porous objects, and constructs with encapsulated polymer particles and metal droplets. In addition, structure flexibility can be easily tuned by changing the droplet size and flow rate. This gives researchers a wide range of options to truly design their structure and vary flexibility to fit their needs in a way that's difficult with the conventional nozzle-based method. Though microfluidic-based 3D printing has been done before, Wan's group is the first to use this droplet-based multiphase emulsion approach. The team is already looking into potential applications and learning what other combinations of materials they can use to change the mechanical or chemical properties of 3D printed products. They think the work could have applications in bioprinting and wearable electronics, like smart fabrics. Long-time Slashdot reader mi also notes there's been recent interest in 3D-printing living tissue — and then shares an even more interesting recent paper on "biomaterial formulation and robotic methods" for "the biofabrication of 3D tissue-engineered scaffolds inside of a living patient." In other words, 3D-printing tissue directly into the body.

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