Most medical devices come in standard sizes, but people – as you've probably noticed – vary widely in their shape and size. Sick or premature babies especially can run afoul of this system, as their tiny bodies leave much less room for error in inserting or attaching devices at the correct spot. But in the near future all biomedical equipment may be 3D printed at precise dimensions to suit each patient.

Researchers at Northeastern University are developing a 3D printing technology for exactly this purpose. Their method uses ultralow magnetic fields to precisely align ceramic fibers with liquid plastic in a similar way to how the human body orientates calcium phosphate fibers in bone around blood vessel holes – in the process reinforcing the bone's strength. If the fibers are not aligned parallel to the direction of stress/geometry, the structure is left weak and may not withstand the force of oxygen, fluid, or nutrients flowing through it.

After this alignment step, the researchers then use a process called stereolithography to stack layers atop one another and harden the plastic with a computer-controlled laser beam.

By keeping control over how the ceramic fibers are arranged, the researchers gain the ability to fine-tune the mechanical properties of the material itself. This allows them to adjust the configuration of holes, corners, curves, and size of catheters (thin tubes) and other devices to match the specific needs of the patient.

Study lead author Randall Erb received a US$225,000 Small Business Technology Transfer grant from the National Institute of Health to use the technology to develop catheters for newborn babies. He says it also hoped that surgical implants can be designed using this 3D printing method.

A paper describing the research was published in the journal Science.