A bioactive polymer-ceramic composite for fixing implants and restoring bone defects in the skull was developed by an international group of materials scientists from the Center for Composite Materials of NUST MISIS. The innovative composition of the material based on bioceramic from eggshell provides increased strength and bio integration of implants. The results of the work were published in the international scientific journal Journal of Asian Ceramic Society.
National Research Technological University “MISiS” – Russian Technical University; the first university in the country to receive the status of “National Research Technological University”.
Polymethylmethacrylate (PMMA) is a synthetic polymer used by surgeons as “bone cement” due to its self-curing properties and strength. But this material is inherently bio-inert, therefore it has weak chemical and biological interactions with living tissues and is difficult to integrate with bones.
The team of the NUST MISIS Center for Composite Materials solved this problem by modifying polymethyl methacrylate by adding diopside, a material from the category of silicate bioceramics. It is known for its lack of toxicity to living cells, biodegradability, and the ability to stimulate osteogenesis – the formation of bone tissue on its surface.
Eggshells have health benefits such as bone mineralization and growth, treatment of osteoporosis, and therefore are used as a bone graft. We have adopted a cost-effective approach to biowaste recycling to improve the quality of life for patients with bone disease. In the production of composites, the diopside obtained from eggshells was used.
Inna Bulygina, co-author of the study, student of the Faculty of Biomaterials Science, IFN NUST MISIS
The developers proposed to optimize the material by adding bioactive ceramics to the PMMA polymer matrix.
As a result, the scientists obtained a porous composite material PMMA / diopside, which was produced by the method of solvent casting. During the experiments, the researchers tried different proportions of diopside – 25%, 50%, and 75%
The process of bone formation and resorption is regulated by several agents, including growth factors, proteins, and hormones. At the same time, various ions such as phosphorus, calcium, strontium, magnesium, and silicon dioxide are involved in the regeneration, mineralization, and metabolism of bones, and it is these elements that ensure the introduction of diopside into the composite.
Samples containing 50% diopside showed the best result – they showed a 4-fold increase in compressive strength and after 4 weeks of in vitro testing showed a good ability to deposit bone minerals on their surface. The mechanical properties of the obtained porous composites correspond to those of the spongy bone of the human body.
According to scientists, waste from the agricultural and food industries can be used for the industrial production of surgical material. However, collection, cleaning and recycling will require separate collection of waste.
Currently, the developers are completing a series of laboratory tests of the samples obtained.