Silicon in living organisms and new-generation biocomposite materials (review)

Abstract

The effect of silicon compounds on the formation and growth of natural bone tissue is examined, and the concentrations of silicon compounds in different organ tissues are presented. The inductive action of different implantation substrates containing silica on the vital activity of cultures of osteogenic cells is described. It is suggested that the process resulting in bonding between bone tissue and silicate implantation material is affected by the presence of a substantial number of silanol groups on the surface of the material, which determine its high hydrophilicity. It is shown that the solubility of silicate glasses depends on the presence in them of a phase which corresponds to the composition of liquid glass, and its role in the biodegradation of the materials in physiological media is described.Modern surgical methods of treatment in medicine are aimed not at removing a damaged organ bur rather to restoring its biomechanical properties. John Wolf's law (1872) -at the root of every regeneration lies nature's aim to restore not form but function -is the theoretical validation for the development of these directions in surgery and medical materials science. For bone -plastic surgery W. Roukes (1893) proved that bone possesses functional form and structure because of the functional stimulation of cells, which intensifies blood flow to the bone and results in its growth and, vice versa, decreased nutrition results in atrophy.The advancement of restorative and replacement surgery became possible as a result of the development, first and foremost, of calcium -phosphate implantation materials which possess biological activity and stimulate the growth of bone cells. One such material is the porous apatite-silicate biocomposite BAK-1000, which as a result of the differentiated porous structure possesses osteo-conductivity [1]. Clinical experience gained over the last fifteen years of clinical experience in using implants based on the biocomposite BAK-1000 has demonstrated that this material is effective in neurosurgery and facial-maxillary surgery was well as in surgical stomatology. The advantage of this material over analogous calcium-phosphate composite materials is due to the presence in its structure of a hydrated silicate matrix, which makes its biological properties close to materials based on hydroxyapatite (HA) and bone protein -collagen [2].

Effect of sintering temperature on the properties of biogenic hydroxyapatite–glass composites

“…Therefore, BHA dissolves in the internal environment to produce calcium and phosphorus ions needed to form bone tissue and sodium borosilicate glass dissolves to produce silicon ions extremely important for the normal growth and development of skeleton tissue. In the initial stage of bone biomineralization, silicon initiates the deposition of bone minerals and is an important 'transition' element in the formation and development of cartilage and bone structures [13].…”

Production of SiO2–P2O5–CaO–(Na2O) structured films

“…One obvious reason is an increase of the content of hydroxyl groups as a result of the interaction of calcium and sodium chlorides with water, which promotes the development of hydrolytic polycondensation processes. Apparently, another reason is the interaction of silanol groups with the phosphate component in a neutralization reaction, which, in the opinion of the authors of [5], occurs in such solutions, and then interaction of the reaction product with calcium ions, which stabilizes the silicate gel owing to the formation of the three-dimensional structure …”

Biocomposite material based on dicalcium phosphate dihydrate

“…The IR spectra of the b-Ca 3 (PO 4 ) 2 obtained contains absorption bands corresponding to vibrations of PO 4 3-groups According to the findings of electron microscopic analysis, precipitated b-Ca 3 (PO 4 ) 2 is represented by agglomerates 0.5 -50 mm in size. After heat treatment, the tricalcium phosphate crystals are round and are no larger than 0.5 mm.…”

“…The IR spectra (Fig. 2b ) contained vibrations of HPO 4 3-, CO 3 2-, and OH -groups. The bands in the 1300 -1700 and 2300 -2450 cm -1 regions are characteristic of hydrophosphates and are considered combination bands forthese anions.…”

“…- The investigated additives are additional sources of silicon ions which are present in bone tissue in the amount of 17´10 -4 % and participate in biological processes [4]. The silicon boosts cell activity; it increases output of type I collagen by the cells in the stage of formation of organic bone matrix (osteoid), and later in the mineralization stage, causes precipitation of calcium phosphates.…”