3D Printable Bones Introduced by Johns Hopkins Researchers
Over 200,000 people are in need of a replacement for the bones on their skull and face. Researchers of Johns Hopkins told that the problem is caused by the rising numbers of people who have cancer or trauma, or because of a birth defect. The usual procedure for bone replacement is to get a part of the fibula from the patient for the doctors to carve the exact shape needed. After that, they will put it back again to the patient and let the bone grow and heal. However, this is not the best solution in replacing the bone because it is quite difficult for a doctor to come up with the desired shape and fit it to the patient’s face. This can also leave scars on the face and can cause stress on the patients’ leg that will add up to the trauma that they feel on their face.
The Creation of 3D Bone Scaffold
With the help of Warren Grayson from Johns Hopkins University School of Medicine who work there as a professor of biomedical engineering, bone scaffolds that were 3D printed was introduced. By combining man-made, pulverized material from natural bone, and biodegradable plastic, they have created the 3D printed bones. These bones will start to grow again once planted in the patient’s body. The plastic scaffold will be broken down slowly while the body absorbs it.
The team of Grayson made a composite material that shows durability wherein the 3D printed plastic material has the biological information enclosed to the natural bone. They have used polycaprolactone or PCL which is a biodegradable polyester material. It is strong and can easily melt inside the body making it ideal for bone replacement. The only problem is, the bone can hardly regrow. They have also combined a pulverized porous structure from cows strip to the PCL.
Various Mixtures of Bone Powder and PCL Tested by Grayson
For them to create the exact framework of the 3D printed bone, Grayson conducted his experiment of mixing the bone powder and the PCL. They have found out that the smallest amount of pulverized natural bone is around 30% that will be mixed with 70% of PCL. They have also tried mixing 70% of bone powder to 30% of PCL and a mixture of 85% bone powder to a small amount of PCL. However, the bone replacement needs sufficient amount of PCL in order maintains its shape. As a result, they ended up testing the 30% and the 70% mixtures by exposing them to a broth material with stem cells derived from fats.
During the experiments, they have discovered that there is a greater chance of bone formation for the 70% scaffold compared to the 30% scaffold. They have implanted the bone scaffold to rat skulls and found out that the bone grows better for the scaffold that contains bone powder than those made up of PCL.
Grayson and the team are still in the process of discovering the exact ratio of bone powder and PCL. Though the bone regrows for the 70% mixture, the durability of the material is not as strong as the 30% mixture. They will also begin experimenting human bone because of its availability. They are planning to create a natural scaffold that looks exactly the same with the real bones. They will conduct some tests on how they can encourage the growth of blood vessels in the scaffold in order to keep thicker bone replacement alive.