Researchers develop 3-D printing method for creating patient-specific medical devices

November 03, 2015

A team of researchers at Northeastern University has developed an innovative 3-D printing technology that uses magnetic fields to shape composite materials--mixes of plastics and ceramics--into patient-specific products. The biomedical devices they are developing will be both stronger and lighter than current models and, with their customized design, ensure an appropriate fit. Their paper on the new technology appears in the Oct. 23 issue of Nature Communications.

One specific application of this new technology is developing patient-specific catheters, especially for premature newborns. Today's 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."

Others have used composite materials in 3-D printing, says Joshua Martin, the doctoral candidate who helped design and run many of the experiments for the paper. What sets their technology apart, say Erb and Martin, is that it enables them to control how the ceramic fibers are arranged--and hence control the mechanical properties of the material itself.

That control is critical if you're crafting 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. This is the strategy taken by many natural composites from bones to trees.

Consider the structure of human bone. Fibers of calcium phosphate, the mineral component of bone, are naturally oriented just so around the holes for blood vessels in order to ensure the bone's strength and stability, enabling, say, your femur to withstand a daily jog.

"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 3-D printing method aligns each minuscule fiber in the direction that conforms precisely to the geometry of the item being printed.

"These are the sorts of architectures that we are now producing synthetically," says Erb, who 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. "Another of our goals is to use calcium phosphate fibers and biocompatible plastics to design surgical implants."

The magnets are the defining ingredient in their 3-D printing technology. Erb initially described their role in the composite-making process in a 2012 paper in the journal Science.

First the researchers "magnetize" the ceramic fibers by dusting them very lightly with iron oxide, which, Martin notes, has already been FDA approved for drug-delivery applications. They then apply ultralow magnetic fields to individual sections of the composite material--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."

Finally, in a process called "stereolithography," they build the product, layer by layer, using a computer-controlled laser beam that hardens the plastic. Each six-by-six inch layer takes a mere 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."

Northeastern University

Related Magnetic Fields Articles from Brightsurf:

Physicists circumvent centuries-old theory to cancel magnetic fields
A team of scientists including two physicists at the University of Sussex has found a way to circumvent a 178-year old theory which means they can effectively cancel magnetic fields at a distance.

Magnetic fields on the moon are the remnant of an ancient core dynamo
An international simulation study by scientists from the US, Australia, and Germany, shows that alternative explanatory models such as asteroid impacts do not generate sufficiently large magnetic fields.

Modelling extreme magnetic fields and temperature variation on distant stars
New research is helping to explain one of the big questions that has perplexed astrophysicists for the past 30 years - what causes the changing brightness of distant stars called magnetars.

Could megatesla magnetic fields be realized on Earth?
A team of researchers led by Osaka University discovered a novel mechanism called a ''microtube implosion,'' demonstrating the generation of megatesla-order magnetic fields, which is three orders of magnitude higher than those ever experimentally achieved.

Superconductors are super resilient to magnetic fields
A Professor at the University of Tsukuba provides a new theoretical mechanism that explains the ability of superconductive materials to bounce back from being exposed to a magnetic field.

A tiny instrument to measure the faintest magnetic fields
Physicists at the University of Basel have developed a minuscule instrument able to detect extremely faint magnetic fields.

Graphene sensors find subtleties in magnetic fields
Cornell researchers used an ultrathin graphene ''sandwich'' to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

Twisting magnetic fields for extreme plasma compression
A new spin on the magnetic compression of plasmas could improve materials science, nuclear fusion research, X-ray generation and laboratory astrophysics, research led by the University of Michigan suggests.

How magnetic fields and 3D printers will create the pills of tomorrow
Doctors could soon be administering an entire course of treatment for life-threatening conditions with a 3D printed capsule controlled by magnetic fields thanks to advances made by University of Sussex researchers.

Researchers develop ultra-sensitive device for detecting magnetic fields
The new magnetic sensor is inexpensive to make, works on minimal power and is 20 times more sensitive than many traditional sensors.

Read More: Magnetic Fields News and Magnetic Fields Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to