Bone Made Of Wood?

When you think about it, bone made of wood makes sense. They're both hard, solid, living elements with a porous interior that support a growing, living system. The continuing need for materials to aid in bone regeneration has encouraged a group of scientists from the Institute of Science and Technology for Ceramics in Faenza, Italy to take a closer look. These scientists are working on a project called TEM-PLANT, and they have become the first to use wood as a substitute in biomedical engineering.

The Discovery

A piece of Red Oakwood was placed into a special oven where it became charcoal. Charcoal is made of carbon molecules and bone is made of calcium molecules. Calcium is then sprayed over the charcoal. With the right combination of pressure, temperature, and chemicals, scientists are able to modify the molecules of the implant. This tedious process is done molecule-by-molecule until the entire piece of charcoal has been changed to a carbonate hydroxyapatite.

^{_{Red Oakwood to charcoal. Image Credit: R&D magazine}}

Current technology in bone repair and regeneration utilizes metallic rods, which, while providing support for load bearing, do not easily facilitate bone regeneration. Metals such as titanium are not bioactive and therefore cannot interact with living tissue. This means that when a titanium implant is put into a patient it is encapsulated by fibrous tissue. The metal weakens, causing the implant to fail. Scientists are hoping that the use of wood would allow for support and regeneration to occur at the same time since the physical structure of wood is spongier than current implant materials. The entire process takes about one week and costs about $850 for a single block. One block translates to about one bone implant.

^{Intramedullary Rod. Image Credit: Rrearl}

Another advantage to using wood is that it's already a biological and biodegradable material. The transformation from wood to charcoal is totally natural with no synthetic or hazardous by-products produced at any stage. Once modified, the charcoal is identical to the mineral part of the bone (hydroxyapatite, which makes up 80% of bone) and acts as a ceramic. Charcoal also has sub nanostructured properties that make it ideal for implantation. Since the charcoal is recognized as if it were an autologous bone, it can be inserted into a gap in a fracture bone. It then stimulates the surrounding cells to wrap themselves around the implant and incorporate it, which forms new, healthy bone tissue. The charcoal will gradually disappear according to the amount of bone regenerated. Due to the bio inert properties of charcoal, researchers don't have anything that suggests rejection of the implant. These properties should allow live bone to heal faster and more securely after a break.

"At the moment, only about 20 sheep have received these bone replacements and they seem to respond very well", assures Anna Tampieri, a scientist at the Instituto Di Scienza E Techologia Dei Materiali Ceramici in Italy. "Now we have to strengthen the material from a mechanical point of view and have a broader and repeated number of animals".

The Future

There is still significant research being done to determine the best way for surgeons to be able to use the material since not everyone has the same bone problem. Many factors must be considered when repairing bone, such as age and gender of patient, what bone is injured and how much of the bone must be replaced. Scientists do note that the material can be made into many shapes and sizes. No one knows when clinical trials for humans will start; scientists still need to ensure that it is safe enough to be implanted.

But who knows?….in a decade or so, pirates may not be the only ones with wooden legs!