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.


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