28 October 2010

Implants made of biodegradable nanoceramics

Biomaterials for implantologyE.Klimashina, "Nanometer"
The use of materials for the replacement and restoration of bone tissue began more than 2000 years ago, and research in this area is still being conducted to this day.

The main feature of the new millennium is the increasing interest in increasing the quality and duration of human life. Thus, the XX century was marked by a sharp leap in the field of biomaterials for the replacement and restoration of bone tissue, which is associated with the use of hydroxyapatite (HAP) as a bone implant. The innovative use of specially designed ceramic materials for the treatment of sick or damaged body parts opens the way to an increase in the period of active human life. This field of modern materials science is called bioceramics. It covers materials for endoprostheses in traumatology and orthopedics, filling materials in dentistry, implants in maxillofacial surgery, medical and cosmetic products.

Since childhood, we have all been familiar with the characters from the fairy tale story by A.M. Volkov "The Wizard of the Emerald City", in which the Scarecrow dreamed of brains, and the Tin Woodman dreamed of a heart. There were other characters who would have wanted their bodies back, such as Robocop and Professor Dowell.

Modern developments in the field of biomaterials could help them. Biomaterials are materials designed to replace damaged areas of the body, their individual organs and tissues. For example, a bone fracture or injury leads to the need to replace the damaged area with an artificial implant.

Modern developments in the field of biomaterials and approaches to their creationSince the first attempts to use calcium phosphates in medicine, the concept of using biomaterials has undergone major changes.

The so-called regenerative approach has come to the fore, in which the emphasis is on replacing the biomaterial with native (own) growing bone, the material is assigned the role of an (active) source of elements necessary for the construction of bone tissue. It is expected that the "ideal implant" should gradually dissolve in the environment of the body, while performing its supporting functions, and new bone tissue should form in its place. It is obvious that the resorptive function (dissolution) of the biomaterial is extremely important for the successful integration (introduction) of the material into the body. The rate of bone regeneration depends on several factors, such as porosity, composition, solubility and the presence of certain chemical elements that come out during resorption (dissolution) of ceramic material, facilitating bone regeneration carried out by special cells, osteoblasts. Compared with calcium hydroxyapatite Ca 10(PO 4)6(OH)2 (HAP), which is actively used in medical practice, a material based on nanoscale carbonate-containing hydroxyapatite Ca 10-x Na x(PO 4)6-x(CO 3)x(OH) is considered promising2 (KGAP). It has a number of advantages: it more accurately reproduces the composition of bone tissue compared to HAP and has increased bioresorption and osteoinduction. This means that the nano-CAA implant, gradually dissolving, will be replaced by a newly formed natural bone, which will completely replace the implant.

Micrograph of nanocrystalline carbonate hydroxyapatite

Micrograph of a ceramic pellet
made of nanocrystalline carbonate hydroxyapatite ("mini-implant")With the development of bioengineering technologies, it will be possible to create bone tissue in a natural biological way using stem cells.

For example, it will be possible to create dental rudiments that will naturally germinate after implantation. However, according to forecasts, only biomaterials of artificial (synthetic) origin will be really available in the coming decades.

List of used literature:
E. S. Kovaleva et al., Carbonated hydroxyapatite nanopowders for preparation of bioresorbable materials. Mat.-wiss. u. Werkstofftech, 2008, v.39, No. 11, p.822-829.
S.I. Stupp et al., MRS Bulletin, 2005, No. 30, p. 864.

Portal "Eternal youth" http://vechnayamolodost.ru28.10.2010

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