3D printing has enabled the production of medical devices tailored to a patient's needs but, often, they are made using solid and inflexible materials.
As a result, these devices restrict movement; using them can be inconvenient and uncomfortable. Moreover, they are not ideal to support the recovery of joints and muscles, which are more complex and nonlinear.
Recently, engineers from MIT demonstrated 3D-printed mesh materials that offers support for softer tissues.
Flexible Wearable Supports
The flexible meshes were inspired by fabrics and collagen, the protein in the body that make up connective tissues. Sebastian Pattinson, a postdoc at MIT, designed the materials with the molecular structure of collagen in mind: he created wavy patterns which he 3D-printed using thermoplastic polyutherine. He then fabricated a mesh configuration that stretchy, tough, and pliable like fabric.
To test, the team printed long strips of mesh and attached them on the outside of the ankle of several healthy volunteers. They used an ankle stiffness measurement robot, which is aptly named Anklebot, to examine how the mesh affected movement in different directions.
They reported that the material increased the ankle's stiffness during inversion, a common cause of injury, but had no effect to movement in other directions.
The researchers also fabricated a knee brace design that conforms to a patient's knee even as it bends and a glove that conforms to the wearer's knuckles to prevent involuntary clenching following a stroke.
The researchers also discussed the potential of the 3D-printed flexible mesh as an implantable device to support hernia. For this purpose, they explained that a stiffer material is ideal. However, it still has to be just as conformable.
They incorporated stainless steel fibers over the regions of the pliable mesh that would need stronger support. They placed another layer of the elastic mesh over the stiffer thread.
The result is a comfortable combination of stiff and elastic material that can easily stretch up to a point and then start to stiffen to prevent a muscle from overstraining.
Pattinson and colleagues imagined that their 3D-printed mesh can be used in a variety of ways.
The research was published in the journal Advanced Functional Materials on Wednesday, June 19.