Could wood be a practical replacement for bone? Researchers from the National Research Council of Italy (CNR) writing in a forthcoming issue of the International Journal of Healthcare Technology and Management suggest that it can. It turns out that the structure of some woods at the microscopic level is very close to that of natural bone; both have unique biomechanical properties such as high strength and lightness.
Two researchers in Italy, Ugo Finardi (Institute for Economic Research on Firms and Growth-CERIS-CNR, and University of Torino), and Simone Sprio (Institute of Science and Technology for Ceramics – ISTEC-CNR), have carried out a case study on the implications of a new technology recently developed by the Research Group on Biomaterials of ISTEC. In that work, the researchers, Anna Tampieri, Simone Sprio and Andrea Ruffini, used a nanotechnological approach to transform rattan wood into hierarchically organized implants.
They say that these biomimetic materials have a strength and flexibility similar to natural bone, something that cannot be achieved with current metal alloy technologies. They believe that the structure of rattan wood might be used as a scaffold for creating a synthetic material to replace damaged and lost bone. An additional benefit is that such a material could be load bearing, a factor that has precluded the use of earlier biomimetic materials.
The processing of raw wood to remove chemical components incompatible with implants for humans involves heat treatment of the wood to remove cellulose, lignin and other plant materials but to leave behind a carbon skeleton that can then be infiltrated and reacted with calcium, oxygen and phosphate to make a porous material, chemically and mechanically mimicking bone.
The research team says that unlike metal alloys, ceramics and even donor bone, their patented material is low cost, has very good biomechanics, is biocompatible and can be integrated into existing bone, thus assisting in bone regeneration. The team notes that more than 2.2 million bone grafting procedures are performed annually around the world. Moreover, this number is increasing as lifestyles change and the world population experiences progressive aging. More information on this process can be found in “Human bone regeneration from wood: a novel hierarchically organized nanomaterial” in International Journal Healthcare Technology and Management, 2012, 13, 171-183.
Dr. Sprio told OTW senior writer Elizabeth Hofheinz: “Human bones have a hierarchically organized morphology which develops over different dimensional scales, from the nano- to the macroscopic one. This feature is the key for the outstanding mechanical performances of bone and for its ability to self-repair upon limited damage. A very challenging aspect of this study was to find a way to reproduce artificially this very complex structure, since no manufacturing processes exist. It is believed that if an organized structure similar to bone in chemistry and morphology is implanted, the cells will be stimulated to form new bone with organized structure and functional.”
“The big jump was when we realized that it would have been possible to copy existing structures from nature, in particular some woods such as rattan, into inorganic materials with the same composition of bone. However it was hard to conceive and set up the complex transformation process to transform wood into hydroxyapatite (i.e. the mineral part of bone), and maintain the original structure and morphology of the wood.”
“Bone diseases involving long and load-bearing bones can occur following big traumas or tumors; that can also result in very comminuted fractures in turn possibly resulting in infections and limb amputation. Hence, such diseases have a very strong socio-economic impact also reflecting on familiars and relatives.”
“The device we developed is potentially able to rapidly integrate with the existing bone and to induce its regeneration, thus avoiding the repeated surgery and allowing the patient to recover the limb functionality in a relatively short time (possibly six months). To do this, about five to seven years would be necessary–to perform advanced in vivo experimentation on animal, human testing, CE validation and commercialization, and hoping that everything will go on the right direction.”
