Researchers Use DNA as ‘Smart Glue’ to Provide Structure for 3D Bio-Printing

The abilities of 3D printing to create bio-materials is on the cutting edge of science, but has been somewhat limited to date by technicalities like massive expenses and the fact that 3D printing using microscale materials would lead to microscale products. These factors have so far severely limited the potential for applications including 3D printing living tissues and organs.

A team of researchers from the University of Texas at Austin‘s Department of Chemistry and Biochemistry, consisting of Peter B. Allen, Zin Khaing, Christine E. Schmidt, and Andrew D. Ellington, have published a new paper in the American Chemical Society‘s ACS Biomaterials Science & Engineering journal. The paper, “3D Printing with Nucleic Acid Adhesives,” explores the novel idea that DNA could be used, not just as a concept in 3D bio-printing, but as an actual adhesive to glue together the materials used in additive manufacture of lab-grown tissues and organs. The DNA-as-glue theory would provide a new, significantly less expensive, process to create viable bio-materials.

Existing methods of 3D printing with nano materials have some major drawbacks, including prohibitively large costs and problematically small prints. Nano-sized bio-prints aren’t much good once techniques start to progress beyond the theoretical. Now that researchers know that the process is possible, they can begin adapting it to actual usage. Applications that stand to benefit from developments in this arena include injury repair, such as of torn tissues, and, on the bigger scale, 3D printing entire organs for those on transplant wait lists.

Larger creations required thinking out of the box, and Andrew Ellington and team appeared to be up to the challenge. They developed nanoparticles — of polystyrene or polyacrylamide — that were coated with DNA, which acted as a glue to hold these lower-cost materials together. DNA can interact in predictable ways with other strands of DNA, creating what these researchers dubbed “smart glue,” which can create a colloidal gel with a shape stability. This colloidal gel can, in turn, be used as the material in their 3D printer to produce objects that can actually be seen with the naked eye, and interacted with in such a way that does not necessitate a microscope — unlike previous usage of nucleic acids in 3D printing.

Utilizing the “DNA:DNA interactions” that they could understand, the research team was able to manipulate the resultant colloidal gel — without a microscope — for better control. Through experimentation, they were able to show that these gels could provide a human cell growth environment, which, while being a huge step forward, is still the first of many on creating actual full tissues in the lab. The ultimate hope is to create viable scaffold materials that will grow tissues.

In their paper, the research team presents four major findings of their DNA smart glue:

1. After extrusion through the 3D printer, the colloidal gel holds its shape.
2. Some control over the microscale structure results from the DNA binding of the particles.
3. Costs are “dramatically reduce[d]” through use of the DNA coating, and macroscale applications become viable.
4. Bio-friendly assembly of the material’s matrix can host growing cells.

A) ABS Plastic, B) 3D printer output, C-E)DNA cross-linked colloidal gel printed into a pyramid shape with extrusions rates of 1.3, 1.7, and 2.1 uL/s

These findings pave the way for a significant amount of future works and development, providing a new and visible-to-the-eye base from which to work. It no longer seems like a far-fetched idea that entire human organs will be able to be created via 3D printing.

What do you think about this latest research? Did you ever expect to see 3D printed human tissues and organs in your lifetime? Tell us your thoughts in the DNA as “Smart Glue” forum thread at 3DPB.com.