Scientists of the Composite Materials Center at the Moscow Institute of Steel and Alloys have developed a material for bone implants with the ability to recover its own cracks. The substance is based on a polymer with the shape memory effect, which restores its structure under local heating. The results of the research were presented at the videoconference "Scientific and Technological Solutions for Future Medicine" (Moscow-Delhi), which took place at the Moscow-based international news agency "Russia Today".
It is about the possibility of replacing small or large parts of the bone in case of injuries and removal of bone tissue fragments when a malignant tumor is found. The human body does not have the resources to independently restore a big amount of bone tissue, so there is a need for implants.
If the implant inside the body is subject to cyclic stress (this usually occurs when bone fragments are replaced in the limbs, especially the legs), it gradually develops cracks, the appearance of which is very difficult to control. It is impossible to prevent the cracks, but there is a possibility to produce implants from a material with the self-recovery property.
“We are developing the method of applying materials with the shape memory effect,” - Fyodor Senatov, Ph.D. in Physics and Mathematics, a research associate at the Center for Composite Materials of the Moscow Institute of Information Technologies and Mathematics explains. “Initially, the implant has a particular shape, which is later altered by a crack. However, when heated, the structure is restored. The shape memory effect requires the coexistence in the polymer of a rigid phase (chemical or physical seams, interlacing of molecules or intermolecular interactions) and a soft phase, which determines the entropic elasticity of macromolecules and can be deformed into a temporary shape”, - he added.
At the moment, experiments are being conducted in various laboratories around the world to study the possibilities of local heating of such an implant without affecting the surrounding tissues. To heat it, you need to perform a minimally invasive surgery, that is, make a puncture and bring the waveguide straight to the replaced bone fragment. The main problem is that the shape of the implant can be restored at the temperature of over + 50 degrees, which may cause great damage to living cells. In addition, the temperature of activating the shape memory effect is high for the polymers suitable for use in bone implants.
"Unfortunately, at the moment, mankind does not have any material that is solid and strong, on the one hand, and easily transforms its structure at acceptable temperatures, on the other hand. I think we should experiment with the technology of cautious heating or find the optimum by creating composite materials and changing their internal structure. We could tap into such compositions, but so far their self-recover occurs under the temperature of +50 Centigrade”, - Fyodor Senatov explained.
Presently, scientists of the Composite Materials Center use different polymers, most of them bioresorbable, as the basis for implants. They can be used to replace little bone fragments, which is in demand in maxillofacial surgery. For large fragments, ultra-high molecular weight polyethylene is used.
Now scientists are experimenting with the composition of materials, trying to strengthen them and at the same time lower the heating temperature required.