Researchers from NortheasternUniversity have developed a new 3D-printing technology that can help create customized biomedical devices that are stronger and lighter than current models.
The technology employs magnetic fields to shape composite materials (mixes of plastics and ceramics) into patient-specific products.
One specific application the team had in mind when developing the technology was patient-specific catheters for premature newborns. The current catheters only come in standard sizes and shapes, which means they cannot accommodate the needs of all premature babies.
"With neonatal care, each baby is a different size, each baby has a different set of problems," says Randall Erb, assistant professor in the Department of Mechanical and Industrial Engineering and lead researcher on the project. "If you can print a catheter whose geometry is specific to the individual patient, you can insert it up to a certain critical spot, you can avoid puncturing veins and you can expedite delivery of the contents."
Using composite materials for 3-D printing is not new, but the team’s technology enables them to control how the ceramic fibers are arranged—in essence controlling the mechanical properties of the material itself.
According to the team, that control is critical if you are creating devices with complex architectures such as customized miniature biomedical devices. Within a single patient-specific device, the corners, the curves and the holes must all be reinforced by ceramic fibers arranged in just the right configuration to make the device durable.
"We are following nature's lead," says Martin, "by taking really simple building blocks, but organizing them in a fashion that results in really impressive mechanical properties."
The 3-D printing method uses magnets to align each minuscule fiber in the direction that conforms precisely to the item being printed.
First, the researchers "magnetize" the ceramic fibers by dusting them very lightly with iron oxide. Then, they apply ultra-low magnetic fields to individual sections of the composite material with the ceramic fibers immersed in liquid plastic, to align the fibers according to the exacting specifications dictated by the product they are printing.
"Magnetic fields are very easy to apply," says Erb. "They're safe and they penetrate not only our bodies—think of CT scans—but many other materials."
Lastly, the team used a process called "stereolithography" to build the product, layer by layer, using a computer-controlled laser beam that hardens the plastic. Each six-by-six inch layer takes about a minute to complete.
"I believe our research is opening a new frontier in materials-science research," says Martin. "For a long time, researchers have been trying to design better materials, but there's always been a gap between theory and experiment. With this technology, we're finally scratching the surface where we can theoretically determine that a particular fiber architecture leads to improved mechanical properties and we can also produce those complicated architectures."
To contact the author of this article, email firstname.lastname@example.org