3D printing plus magnets equals patient-specific medical devices

The vast potential of 3D printing patient-specific medical devices can be a real game changer when it comes to pediatric devices. Because pediatrics is a relatively small market, medical technology companies typically do not devote a great deal of R&D into developing products for children. As a result, adult-sized devices are used to treat much smaller anatomies, with predictable results. Now, researchers at Northeastern University (Boston) have developed an innovative 3D-printing technology that uses magnetic fields to shape composite materials into patient-specific products. The fabrication of appropriately sized catheters for children, and specifically premature babies, is one of the primary applications.

Nearly 500,000 pre­ma­ture babies are born each year in the United States, and catheters are used to provide them with oxygen, nutrients, fluid and medications. However, 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," said Ran­dall Erb, Assis­tant Pro­fessor in Northeastern's Depart­ment of Mechan­ical and Industrial Engi­neering. "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," he explains in a news release published on the university website.

The technology developed by Erb's team aims to produce catheters and other bio­medical devices that are both stronger and lighter than cur­rent models while providing a custom fit. A paper on the new tech­nology appears in the Oct. 23 issue of Nature Communica­tions.

Following nature's lead in medical device design

Although com­posite mate­rials have been used in 3D printing before, the technology developed at Northeastern allows researchers to con­trol how the ceramic fibers are arranged and, thus, con­trol the mechan­ical prop­er­ties of the material itself, explains Joshua Martin, a doctoral candidate who participated in the project. That con­trol is crit­ical because the cor­ners, curves, and holes in a patient-specific device must be rein­forced by ceramic fibers arranged in a precise configu­ra­tion to make the device durable. This biomimetic process is inspired by natural composites found in everything from bones to trees.

"We are fol­lowing nature's lead," explains Martin, "by taking really simple building blocks but orga­nizing them in a fashion that results in really impres­sive mechan­ical prop­er­ties." Using mag­nets, Erb and Martin's 3D-printing method aligns each minus­cule fiber in the direc­tion that con­forms pre­cisely to the geom­etry of the item being printed.

"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 can the­o­ret­i­cally deter­mine that a par­tic­ular fiber archi­tec­ture leads to improved mechan­ical prop­er­ties and we can also pro­duce those com­pli­cated architectures."

Fellow researcher Erb has received a $225,000 Small Busi­ness Tech­nology Transfer grant from the National Insti­tutes of Health to develop the neonatal catheters with a local com­pany. Erb is also working on the design of surgical implants using cal­cium phos­phate fibers and biocom­pat­ible plas­tics.