Bone fractures fixed by 3D bio-printed silk from spiders and moths

Silk cocoons.
Silk cocoons in Dalat, Vietnam. (Photo courtesy of yoyo_hick on flickr.)

Seoul South Korea’s Rural Development Administration (RDA) and Hallym University have collaborated to create a 3D Silk-Printing System that produces components suitable for use in vivo (i.e. within a living organism). The new silk ‘filament’ is made from the fibroin protein that also constitutes 75% of the silk naturally produced by spiders and larvae of members of the moth family.

Fibroin is also used in the production of medical-grade objects because of its bio-compatibility, and has also been the subject of a recent study exploring its potential as a preservative in food. Basically, the fibroin will be used to recreate the plates and screws used to fix broken bones. Once the technology becomes commercialized, it will allow for the production of a greater variety of bio-compatible silk medical equipment, which will help improve South Korea’s health while developing its existing silk production industry.

A surgical plate, screw and clip printed in silk by RDA/Hallym. (Photo courtesy of Yonhap).
A surgical plate, screw and hip printed in silk by RDA/Hallym. (Photo courtesy of Yonhap).

One problem this overcomes is that traditional metal implants, at some point, may have to be removed from the body. Now while this technology is certainly exciting, there are other plastic polymer substitutes trying to solve the same issues. For example, the hyper-elastic bones developed by Northwestern University in Chicago could be one potential solution. Using a commercial 3-D Printer and custom ink formulation, University researchers created a synthetic bone capable of stimulating new bone growth.

Photograph of a 3-D printed hyper-elastic bone of the human spine. (Photo courtesy of Adam E. Jakus, PhD)
Various 3-D printed hyper-elastic bones of the human spine. (Photo courtesy of Adam E. Jakus, PhD).

The bones are created from calcium and plastic composite material. Tests show that samples perform well under compressive strain and, like Seoul’s printed silk, are degradable. However, the calcium composite material has not yet been demonstrated in the same way as the silk, so its potential use as a surgical plate or screw remains speculation for now. Usually, plastic polymers aren’t strong enough for use in fracture surgery. But the ‘silk ink’ described by this research just might be a stronger, more durable and relatively lower-cost option.

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Tony Curcio is the editor of Graphic Arts Magazine.