Artificial bones using nanotechnology

Nanoparticles enable the production of significantly better bone implants

11/21/2011

Researchers at the University of Halle have developed a high-tech process with which they want to produce artificial bones that are better accepted by the body than previous bone implants. With the help of nanotechnology, the artificial bone implants should not only be much more durable in the future, but be recognized by the organism as the body's own material, the scientists report. Georg Michler.

Bone implants are already being used relatively frequently in medicine, with accidents and the involvement of cancerous tumors among the main causes of such interventions. As older people are more prone to bone fractures, demographic change also has an impact on the need for artificial bone implants, according to the statement of the five-member research group headed by Professor Dr. med. Georg Michler of Martin-Luther University Halle-Wittenberg. However, according to the researchers, the disadvantage with the previously used bone implants is that they only have a limited shelf life and are treated as foreign bodies by the organism. To change this, Prof. Dr. Georg Michler and colleagues on the use of nanoparticles with which they want to produce artificial bone implants that last much longer and are no longer recognized by the body as foreign.

Nanotechnology for the production of artificial bone implants
To date, artificial bone implants are made either from the body's own bone or natural foreign bone, the former are only limited available and the latter are encapsulated by the body's own tissue as foreign bodies. The scientists at Martin Luther University have now embarked on a completely new path as part of their research. „We use polymers as carriers for the bone substitute, because they are related to organic substances, and change their properties with the help of nanoparticles“, said the head of research and chairman of the Institute for Polymer Materials of the University of Halle, Prof. Dr. med. Michler. So the researchers took advantage „Nano-calcium phosphate ceramic particles“, to spin them with plastic filaments and make completely new artificial bone implants. For the even distribution of the tiny particles in the plastic, the researchers have developed a special process, whose patent rights lie with the Martin-Luther-University Halle-Wittenberg. Using the novel method, the researchers can use the plastic filaments and the nanoparticles to form a thin foil from which a cylindrical bone implant about eight to ten centimeters long can then be rolled. In doing so, the nanoparticles or „the ceramic inclusions stiff the threads“, which significantly increases the load capacity of the material, explained research director Prof. Dr. med. Michler.

Bone implants are rebuilt into bone substance
In addition to the increased stability of nanoparticle-derived bone implants, the method offers another major advantage, according to the researchers. So stressed Dr. Jörg Brandt, Senior Physician of the Clinic and Polyclinic for Orthopedics and Physical Medicine in Halle and also a member of the research group: „Because the nanoparticles in the artificial bone are so extremely small, the body is able to completely rebuild the bone implant into its own bone substance and thus fully integrate into the skeletal structure.“ The material is no longer encapsulated as foreign matter. As part of their laboratory investigations, the scientists have found that nanoparticles of ten nanometers thickness and 50 nanometers in length are optimally absorbed by the body, whereas „anything smaller or larger, the body does not transform“ could, explained Prof. Dr. med. Michler. Why nanoparticles of the mentioned size are best accepted by the organism is, according to the scientists, also to be clarified in the context of the research project.

Nanoparticles for bone production a very hopeful approach
Also the scientists of other university, which research in the area of ​​the bone implants, such as the material scientist Dr. med. Roland Dersch from the University of Marburg, confirmed that the method of Prof. Dr. med. Michler and colleagues „a very hopeful approach“ be. Dr. Dersch and his team are also working on the possibilities of nano-based artificial bone, albeit with different starting materials. The Marburg researcher emphasized that „much research on nanofibres“ but it has not yet been achieved „to develop a complex artificial bone that is accepted by the human body.“ However, the scientists of the research project at Martin-Luther-University Halle-Wittenberg now seem to be on the right path. Prof. Dr. med. Michler and colleagues, however, not only produce the most durable artificial bones, but also the root cause why bones break at all and why this risk increases with age.

Examine the cause of bone fractures in more detail
Dr. According to Jörg Brandt, around 35,000 hip fractures and femoral neck fractures occur in Germany each year, with older people in particular suffering from such fractures. Many scientists and physicians are convinced of this, „that, for example, old people break the thigh neck in falls.“ Dr. Brandt, on the other hand, believes that most of those affected „have already broken the thigh neck and fall as a result.“ Here further investigations are necessary to go to the properties of the natural bone material to the bottom, because „If we know the processes in the real bone material, we also know what properties the bone implants must have“, stressed Brandt. According to the expert, various scientific studies have shown that bone fractures are generally preceded by microscopic cracking. At a young age these can apparently be counterbalanced by the self-healing powers of the human body. With increasing age, however, the probability increases that a fracture occurs as a result of the cracks, explained the physician.

Use of new bone implants at the earliest in eight to ten years
Dr. According to Brandt, there are first indications for this, „that with the help of the nanoparticles we can give the artificial implant a plastic deformation ability“, what a „improved toughness of the plastic“ would mean. In the two-year research project, which is funded by the German Research Foundation (DFG / Bonn) with about 300,000 euros, all aspects of the production of artificial bone implants with the help of nanoparticles will now be examined in detail. Research Director Prof. Dr. med. Michler stressed that currently the material investigations run and „the individual components of the artificial bone have already been tested for compatibility in animal experiments“ were. The next step will now be clinical trials „the usability of the artificial bone, which is indeed a composite of the components, prove.“, so the conclusion of Prof. dr. Michler. However, even with extensive success in the upcoming investigations, the regular use of the new implants can be expected at the earliest in about eight to ten years. (Fp)

Picture: Rainer Sturm