Composites from mixtures of potassium polytitanate and biocompatible glasses

Abstract

The possibility of synthesizing ceramic composites from mixtures of powders of two types of biocompatible glass and potassium polytitanate was investigated. It was shown that during the reaction of these composites with a solution simulating blood plasma, a porous structure reinforced with potassium hexatitanate or calcium titanate fibers formed on the surface of the material; the pores were filled with hydroxyapatite, which should cause intergrowth of bone tissue in the structure of the implants made from them.Calcium orthophosphates in the form of finely crystalline nonstoichiometric Na-, Mg-, and carbonate-containing hydroxyapatite, so-called biological apatite, are the basic inorganic component of solid tissues in the bodies of mammals. In addition to the calcium orthophosphates that constitute (by weight) 50 -60% of bone, the other basic components of bone are collagens (30 -40%) and water (up to 10%). Different types of bioceramics have been obtained by inorganic synthesis. The high affinity with bone tissue and the biodegradability with subsequent replacement by newly formed bone are considered to be the advantage of Cerasorb bioceramic made of Ca 3 (PO 4 ) 2 (calcium orthophosphate) and Ca 5 (OH)(PO 4 ) 3 (hydroxyapatite) over other synthetic materials. Calcium orthophosphates in bioceramics belong to the category of bioactive and bioresorabable materials. Dissolved, they cause formation of a layer of biological apatite which results in the appearance of chemical bonds between implant and living bone and fusion to the bones, and these implants can bear mechanical loads [1]. The creation of a bioceramic with a porous structure with mechanical characteristics similar to those of living bone is important. For this reason, bioceramics began to be made macroporous (pore size greater than 100 mm) by adding blowing agents which are either volatile or readily soluble compounds (for example, naphthalene, saccharose, NaHCO 3 , NaCl, gelatin, polymethyl methacrylate microbeads) [2]. The implant must be hydrophilic and have a biodegradation rate corresponding to the rate of formation of new bone -from several months to two years.The properties of bioceramics are being improved in several directions -synthesis of ion-substituted calcium orthophosphates, creation of nanocrystalline structures, organomineral hybrids, ceramic fibers, microbeads, porous three-dimensional structures from hydroxyapatite and two-phase calcium phosphate, and biocercamics with a porosity gradient. Synthesis of composites simulating the composition and properties of bone tissue is being supported, and the study of nanostructured and nanocrystalline materials made of calcium orthophosphates to simulate the complex hierarchical structure of bones and teeth is expanding.The composites are usually mixtures of several different components: an inorganic substrate containing elements of bone tissue growth factor or organic matrices with inorganic additives. Such materials as Kolapol, Hapcol, Biomatrix, etc., were created from hydroxyapatite and collag...

Development of bioactive and biocompatible ceramic composites based on potassium polytitanate

“…The semi-crystalline or amorphous potassium polytitanate precursor (K 2 O · nTiO 2 ) synthesized by the molten salt method [15] may be considered as a reinforcing material of composites. This is supported by the tendency of potassium polytitanate (K 2 O · nTiO 2 ) to crystallize after an additional heat treatment at temperatures higher than 800-850°C, as fibre-shaped potassium tetra or hexatitanate, depending on the ratio n = TiO 2 /K 2 O in the original composition [16,17].…”