Researchers Use DNA as Glue To 3D Print Precursor Organs

 Biotech  

Scientists have used DNA as a smart adhesive for 3D printing.  The method may lead to 3D printed tissues and self-assembling organs in the future.

The “source code” for life in humans, plants, animals and some microbes, DNA is the molecular computer that controls how life develops. But now researchers report an initial study showing that the strands can also act as a glue to bind together 3D printed materials that could someday be used to grow tissues and organs in the lab.

This first-of-its-kind demonstration of the inexpensive process is published in the new journal ACS Biomaterials Science & Engineering.

Andrew Ellington and colleagues explain that although researchers have used nucleic acids such as DNA to assemble objects, most of these are nano-sized — so tiny that humans can’t see them with the naked eye. This is the case with DNA origami.  Making the structures into larger, visible objects is cost-prohibitive.

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The current methods of working with DNA also do not allow for much control or flexibility in the types of materials that are created. Overcoming these challenges could potentially have a big payoff — the ability to make tissues to repair injuries or even to create organs for the thousands of patients in need of organ transplants. With this in mind, Ellington’s group set out to create a larger, more affordable material held together with DNA.

The researchers developed DNA-coated nanoparticles made of either polystyrene or polyacrylamide. DNA binding adhered these inexpensive nanoparticles to each other, forming gel-like materials that they could extrude from a modified MakerBot Replicator 3D Printer.

For this study, the 3D printer was modified for printing microparticle-based gels by directing the print head to extrude a suspension provided via a programmable syringe pump. By actuating the print head while controlling the dispense rate of the syringe pump, the 3D printer directed the extrusion of a colloidal gel into 3D shapes.

"The ability to control the macroscale shape, the microscale topology by DNA computation-mediated self-assembly, and the ability to choose the chemistry of the “dumb” substrate material is a unique combination of features for tissue engineering."

The materials were easy to see and could be manipulated without a microscope. The DNA adhesive also allowed the researchers to control how these gels came together. They showed that human cells could grow in the gels, which is the first step toward the ultimate goal of using the materials as scaffolds for growing tissues.

Given the progress that has been made in the DNA nanotechnology community, such programmability may provide an interesting avenue for creating new materials with programmed structure at the microscale.

Future work will focus on controlling the self-assembly process using the properties of both DNA hybridization and DNA circuitry in order to test the effects of different self-assembly processes. By working from the nanoscale to the microscale, to the macroscale, in the future, structures may be self-assembled based on how the seed cells within it are established.

"The ability to control the macroscale shape, the microscale topology by DNA computation-mediated self-assembly, and the ability to choose the chemistry of the “dumb” substrate material is a unique combination of features for tissue engineering," write the study authors.


SOURCE  American Chemical Society 

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