Medical products exactly to measure

Everyone has seen photos of premature babies in intensive care units: tiny wrinkled creatures, some of which weigh a little more than half a kilo, with thin plastic tubes inserted into their noses, mouths and veins. These tubes or catheters deliver oxygen, nutrients, fluid and medications necessary for maintaining its vital activity to the body.

The main problem of modern catheters in this case is that they have standard sizes and shapes, which does not solve the problems of all premature babies. Randall Erb, associate professor at Northeastern University, notes that such children have different sizes and individual complexes of problems. The possibility of creating a personalized catheter, the geometry of which would correspond to the characteristics of a particular patient's body, would allow such a catheter to be inserted to a certain critical depth without the need for vein piercing, as well as increase the rate of administration of the necessary substances.

The researchers working under the leadership of Erb proposed using an innovative three–dimensional printing technology that uses magnetic fields to form personalized medical products from composite materials – mixtures of plastic and ceramics. The products obtained with the help of the new technology, including catheters, will be both stronger and lighter than modern analogues, and their personalized shape will ensure maximum fit.

According to the authors, other groups have already used composite materials for three-dimensional printing, but the new technology differs in that it allows you to adjust the spatial arrangement of ceramic fibers and, accordingly, obtain a material with the desired mechanical properties.

The possibility of such regulation is extremely important when creating products with a complex structure, such as personalized miniature medical devices. One such product can have many elements, such as corners, bends and holes. To ensure the durability of the product, each of these elements must be reinforced with ceramic fibers arranged in a strictly defined configuration. This strategy ensures the strength of many natural composite materials, ranging from bones to wood.

The defining component of the three-dimensional printing technology developed by the authors are magnets, whose role in the formation of composite materials was described by the authors in an earlier paper published in 2012 in the journal Science.

The process proposed by the researchers begins with the magnetization of ceramic fibers by applying a small amount of iron oxide powder to them, the use of which in drug delivery methods is approved by the U.S. Food and Drug Administration (FDA). After that, individual fragments of the composite material, which is a suspension of ceramic fibers in liquid plastic, are exposed to very weak magnetic fields, which ensures the spatial distribution of ceramic fibers corresponding to the specifications of the product being created. A video of the process can be viewed here. 

At the last stage of the process, the final product is formed from the composite mass using the stereolithography method, which consists in layer-by-layer hardening of plastic under the action of a computer-controlled laser beam.

The authors believe that their development opens up a new direction of materials science, as it demonstrates the possibility of theoretically determining fiber configurations that improve the mechanical properties of the material, and the creation of such complex configurations.

Article by Joshua J. Martin et al. Designing bioinspired composite reinforcement architectures via 3D magnetic printing is published in the journal Nature Communications.

Evgeniya Ryabtseva

Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Northeastern University:
Researchers develop novel 3-D printing method for creating patient-specific medical devices.