3D-Printed Bone Heals Injuries Faster

Interesting Engineering

The wonderful world of 3D printing is truly a marvel of modern science. Materials science engineers are applying this flexible technology to the problem of bone healing with 'hyperelastic bone'.

[Image source: Science]

The healing of bones in humans is a long and painful process. In areas of high damage, bone replacement autografts are often used. This technique sees the implantation of bone from one region in the patient's body to another. While one benefit of this approach lies in the use of the patient's own bone, including stem cells to facilitate growth, the procedure requires additional surgery with all of the accompanying pain, recovery time, and potential complications.

Another technique to replace lost bone is the scaffold. Comprising natural and synthetic materials, scaffolds provide a frame upon which stem cells may grow into bone and cartilage. For this process to work effectively, the selected scaffolding material must be hospitable to stem cells and not provoke an immune response. A commonly used material, calcium phosphate, has shown success with the growth of stem cells but is sometimes targeted by the immune system, resulting in zero bone growth. The brittle nature of this material can make implantation problematic and its cost and time to manufacture can also be a factor.

hyperelastic-bone-2[Image source: Science]

Enter 3D printer 'hyperelastic bone'. Developed by researchers at Northwestern University, Illinois, this scaffolding material combines hydroxyapatite, a mineral found in bone, with polycaprolactone, a biocompatible polymer. The material's strength is provided by the hydroxyapatite, as well as chemical cues to stem cells to create bone. Flexibility comes from the polycaprolactone, allowing for ease of implantation.

hyperelastic-bone-4[Image source: Science]

Specialists around the world are taking notice. Biomaterials engineer, Jos Malda from Utrecht University, the Netherlands, said

“This is a neat way to overcome the challenges we face in generating bone replacements. The scaffold is simpler to make than others and it offers more benefits.”

The new material reduces waiting times considerably. Designed on the patient's x-rays, a scaffold made of hyperelastic bone could be 3D printed and ready to be implanted within the day.

Study co-author Ramille Shah said, “We’re printing flexible scaffolds that will encourage bone to grow through and around them.”

Testing of the material in mammals showed no inflammation or infection, with more efficient blood vessel infiltration and bone calcification than in controls.

hyperelastic-bone-3[Image source: Science]

With the constituent materials already in common use in biomedical engineering, Malda reported that hyperelastic bone would be a cost effective solution for bone replacement. The speed of manufacture and adherence to precise specifications opens up a range of possibilities for the technology. Shah continued, “The sky’s the limit for this material’s applications.”

Read the researchers' findings in their newly published Science Translational Medicine paper.