Almost like real
Implants similar to natural bone have been created on the basis of ceramics and synthetic powders
RAS Press Service
Scientists have found a way to create biomaterials from synthetic powders and ceramics based on calcium silicate and its biologically active composites. The implants obtained from them are similar in structure and properties to natural bone and can stimulate its growth in the human body. An article about this was published in the journal Progress in Natural Science: Materials International (Papynov et al., Synthetic CaSiO3 sol-gel powder and SPS ceramic derivatives: “In vivo" toxicity assessment). The research is supported by a grant from the Presidential Research Projects Program of the Russian Science Foundation.
Biomaterials work in direct contact with living tissues and cells inside the body. The largest areas of their application are the production of medical implants, including bone implants. Common cheap and affordable natural materials are used as raw materials, and technologies allow them to be bioactive. Once in the body, such systems interact with bone tissue: stimulate growth, promote migration, division and differentiation of cells.
Such materials have their own requirements. Firstly, they should not have a negative impact on living systems. This is the main condition, which is determined by the chemical composition, surface properties and physical characteristics of the components of the material. Secondly, the artificial bone had to have a porous structure. Only then do the bone cells and blood vessels germinate inside the implant. Thirdly, it is necessary that the material has biologically active properties and can influence physiological processes in the body. Also, its components should not compete with each other in reactions within cells and hinder bone growth. For example, it is impossible to combine calcium and aluminum competing with it in one biomaterial. It has previously been proven that biologically active calcium silicate powder has a positive effect on metabolism.
"It is quite easy to get an ordinary prosthesis made of calcium silicate, which will be inert in the body. And in order to make it biologically active, it is necessary to use special technologies, including new and little–studied ones," says project manager Evgeny Papynov, Candidate of Chemical Sciences, Head of the Laboratory of Composite and Ceramic functional Materials of the Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences (Vladivostok).
The advantage of the created synthetic materials is that during production they can be set the desired characteristics and properties. Then ceramics and calcium silicate powders will take any shape of the required size. Separately, these materials are used in different areas of surgery. Powders are used to combat small maxillofacial defects, bone buildup and dental prosthetics. Ceramics are able to withstand significant loads and are used in larger-scale operations, for example, the replacement of a whole bone or joint.
The authors of the new article have found a way that makes ceramics and calcium silicate powder active when injected into the body, but at the same time the structure and strength necessary for implants will remain. Sol-gel technology was used to synthesize the powder. This is a well-studied and quite popular method in the world: the initial solution becomes a powder of nanoparticles. When working with ceramics, the researchers used an original technology of spark plasma sintering – the synthesis of ceramics from previously obtained calcium silicate powders with various biologically active additives. This technology is still little studied in the world.
"We get biologically active nanostructured powder with a given composition from one raw material. And if necessary, we turn it into dense ceramics of the right size and profile," explains Evgeny Papynov.
The advantage of such products is the combination of a complete set of body–compatible properties of the materials themselves and available methods of their synthesis. And the additives of nanoparticles of precious metals – gold and silver – give the implants antibacterial and anti-inflammatory properties.
The microstructure of calcium silicate powder containing nanoparticles of gold (above) and the surface of synthetic ceramics. Drawings from the paper by Papynov et al.
The prostheses obtained from these materials can be considered a high-quality product. Exceptional biological compatibility allows prosthetics for patients of any age. Also for bone surgery, these are relatively cheap and affordable biomaterials from domestic raw materials. In the future, implants may enter industrial production, and vice versa, they will be in demand in the field of personalized medicine.
The study occupies a priority place in the list of key strategies of the NTR of the Russian Federation and is aimed at the development of high-tech healthcare.
Scientists from the Far Eastern Federal University, Pacific State Medical University and the Pacific Institute of Bioorganic Chemistry named after G. B. Elyakov also took part in the development.
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