Image from Northeastern
Oct 27, 2015
Researchers from Northeastern University have developed a new method for 3D printing catheters for premature babies, as well as other vital medical equipment. In the USA, almost half a million babies are born prematurely each year. These infants require close medical assistance to ensure their survival and good health, with catheters playing an extremely important role in this assistance. The thin plastic tubes, running into a baby’s nose, mouth, or veins, help to deliver essential oxygen, nutrients, fluid, and medicine.
Although their implementation is absolutely vital to the survival of these infants, commonly used catheters are by no means perfect. Models come in standard shapes and sizes, rather than being tailored for the unique anatomy of each patient. This means that, for various physiological reasons, not all premature babies can be catered for. The Northeastern researchers recognised this problem, and sought to remedy it with the aid of 3D printing technology.
“With neonatal care, each baby is a different size; each baby has a different set of problems,” explained Randall Erb, assistant professor in the Department of Mechanical and Industrial Engineering at Northeastern. “If you can 3D 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.”
The 3D printed technology developed by Erb and his team uses magnetic fields in order to shape composite materials—mixes of plastics and ceramics—into 3D printed products tailored for individual patients. The 3D printed catheters, as well as other medical devices, will be stronger and lighter than traditionally assembled alternatives, and their bespoke nature will ensure a perfect fit for each patient.
The most unique and revolutionary part of the researchers’ new technology is its ability to precisely arrange the ceramic fibres of the 3D printed material using magnets, allowing total control of the material’s mechanical properties. There are massive advantages to this tailoring of ceramic fibres: each corner, curve, and hole of the material must be adequately durable to perform its precise medical function. By precisely tailoring the minuscule fibres, medical staff can ensure that the material is as light and noninvasive as possible, whilst ensuring its durability.
“We are following nature’s lead,” explained Joshua Martin, a doctoral candidate who helped design and run many of the experiments for the paper, “by taking really simple building blocks but organizing them in a fashion that results in really impressive mechanical properties.”
The unique 3D printing method uses magnets to align each minuscule fibre in the direction that conforms precisely to the item’s geometry. “These are the sorts of architectures that we are now producing synthetically,” added Erb.
The ceramic fibres of the material are manipulated using magnets and iron oxide. Researchers first “magnetize” the ceramic fibres by dusting them very lightly with iron oxide, a process which has been FDA approved for medical purposes. Ultralow magnetic fields are then applied to individual sections of the composite material to align the fibres exactly in the necessary manner, which, according to Erb, is both simple and safe. “Magnetic fields are very easy to apply. They’re safe, and they penetrate not only our bodies—think of CT scans—but many other materials.”
The product is finally assembled using a technique called stereolithography, a 3D printing technique in which a computer-controlled laser beam hardens each consecutive layer of printed plastic. Each six-by-six inch layer takes only one minute to complete.
“I believe our research is opening a new frontier in materials-science research,” said 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.”
The researchers’ paper, detailing the new 3D printing process in full, can be found in the October 23 issue of Nature Communications.