Ultra high molecular weight polyethylene implant replaced bone tissue or “Iron” polymer

Published on March 28, 2017

Ultra high molecular weight polyethylene implant replaced bone tissue or “Iron” polymer

    Hello! We have news: Russian scientists have successfully tested spongy bone implants based on ultrahigh-molecular polyethylene (UHMWPE *): 100% of the implanted samples have successfully taken root. Researchers from NITU "MISiS" with the help of colleagues from the Blokhin Russian Cancer Center and the State Medical Preparations Plant learned how to create high-precision imitations of the structure of bone tissue, which made it possible to ensure complete replacement of the bone defect, initiate bone regeneration processes and preserve the functionality of the limbs. The article with the results of the study was published in the journal "Materials Science and Engineering". You can get acquainted with it here .

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    No, this is not Hamlet. This is the project manager of Ph.D. Fedor Senates.

    “In the course of new experiments, the research team was able to study the structural and mechanical characteristics of the samples obtained both in vitro and in vivo,” commented Alevtina Chernikova, rector of NITU “MISiS” . “Thanks to the close cooperation of our university, the leading oncological center of Russia and the State Plant of Medical Preparations, the breakthrough fundamental research of scientists of the National University of Science and Technology MISiS has received practical development. In particular, the results of in vivo experiments made it possible to determine the degree of porosity of the inner layer and the size of pores at which there is a strong fixation in the bone defect by growing connective tissue into the implant. "

    Partial replacement of bones destroyed by cancer, injury or surgery remains an important medical problem. In Russia alone, more than 70,000 operations are performed annually to restore the integrity of damaged bone tissue. In the world of such operations are carried out hundreds of thousands.

    Bone tissue has a natural ability to regenerate, but in the case of large defects it may not be sufficient to fully restore the bone. Therefore, today, various types of implants are used to repair damaged bone tissue. The materials used to create bone implants should have a number of specific properties: be biologically compatible with the human or animal body, have high mechanical properties, ensure complete replacement of the bone defect and initiate the processes of bone tissue regeneration.

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    Appearance of ultra high molecular weight polyethylene implants: fully porous and hybrid (outer continuous layer, inner - porous).

    Ultrahigh molecular weight polyethylene is well suited to the criteria described. For example, if we talk about mechanical properties, then in terms of strength / dead weight of a product made from UHMWPE are superior to steel. Therefore, it is potentially very well suited for the manufacture of porous implants, the structure of which most accurately imitated porous spongy bone tissue. However, the extremely high molecular weight of the polymer does not allow the use of traditional methods for creating a porous structure (usually they are created by foaming).

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    A schematic image of a bone into which a two-layer implant of UHMWPE is inserted (its photo is natural), in which the outer layer is solid and the inner layer is porous. The microstructure of the porous layer (scanning electron microscopy) and the microstructure of the cancellous bone (scanning electron microscopy of a dog's bone) are shown. It is seen that the structure is identical.

    The problem was solved by applying the methods of solid-phase mixing, thermal pressing and washing in subcritical water. In this cunning way, a team of Russian scientists for the first time in the world solved the problem of imitating the complex structure of cancellous bone tissue, creating multi-layered UHMWPE frameworks (scaffold **) with a continuous outer and porous inner layer.

    “Our scaffold consists of two layers firmly connected to each other,” tells about the materialWork Manager, Researcher at the Research Center for Composite Materials, NITU "MISiS" Ph.D. Fedor Senates . - The first layer is solid, it imitates cortical bone to ensure mechanical strength. The inner layer has pores of a certain size, so it can be colonized by the cells of the recipient in order to accelerate healing with the surrounding tissues and to ensure a firm fixation of the implant in the area of ​​the defect. "

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    Fedor Senatov with his team

    According to the experimenters, the listed features of the scaffolds obtained on the basis of UHMWPE open up great prospects for creating bioimplants in restorative medicine, which scientists proved in a new series of experiments.

    * Multilayer porous UHMWPE scaffolds for bone defects replacement
    ** scaffold * (scaffold) - the term from tissue engineering (scaffold technology used to regenerate bone tissue).