Co-doped hydroxyapatites as potential materials for biomedical applications

Evis, Zafer
Hydroxyapatite (HA) is a synthetic biomaterial resembling the composition of mammalian hard tissue and thus, it is widely employed as a bone graft material, hard tissue engineering scaffold and coating layer for metallic substrates. Biological apatite is non-stoichiometric in nature. It is composed of small crystals and characterized by poor crystallinity and relatively high solubility with respect to stoichiometric HA. Chemical compositions of these crystals consist of Ca, P and trace amounts of various ions, such as Mg2+, Zn2+, Sr2+, Ag+, Cl- and F- which are more prominent as dopants or adsorbed on the crystal surface. However, these ions play an important role in the metabolism of hard tissues. Synthetic HA is a stoichiometric material with a Ca/P ratio of 1.67, which lacks the presence of valuable trace ions regularly present in natural hard tissue. Thus, the structure of synthetic HA is partially incorporated by these ions to mimic the chemical composition of the biological apatite structure. Ionic substitutions have been planned as a tool to enhance the biological role of HA based materials. As single dopant frameworks have indicated great outcomes, it makes sense that various dopants can be utilized to further build the valuable impacts of each, within the constraints of the material stability of HA. This review is focused on co-ionic substitutions in HA system and their combined effects on related biomedical characteristics.


Biomimetic preparation of HA precursors at 37 degrees C in urea- and enzyme urease-containing synthetic body fluids
Bayraktar, D; Tas, AC (1999-12-01)
An important inorganic phase of synthetic bone applications, calcium hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)), was prepared as a single-phase and sub-micron bioceramic powder. Carbonated HA precursors were synthesized from calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts dissolved in "synthetic body fluid" (SBF) solutions, containing urea (H2NCONH2) and enzyme urease, under the biomimetic conditions of 37 degrees C and pH 7.4, by using a novel chemical precipitation technique.
Öndin, Nilsu; Durucan, Caner; Department of Metallurgical and Materials Engineering (2022-11-22)
Synthetic materials for bone defects have been widely used for biomedical applications. One of these materials is bioactive ceramic-based microspheres in the size range of couple 100s m. These microspheres are used for irregular defect filling operations due to high packing efficiency. The spherical shape also increases the surface area, reactivity, and cell adhesion. The osteoconduction (bone tissue growth) is the primary concern for hard-tissue replacements and grafts. Alpha-tricalcium phosphate (-TCP, ...
Dip coating of calcium hydroxyapatite on Ti-6Al-4V substrates
Mavis, B; Tas, AC (2000-04-01)
Ti-6Al-4V alloy is the most commonly used metallic material in the manufacture of orthopedic implants. The main inorganic phase of human bone is calcium hydroxyapatite (Ca-10(PO4)(6)-(OH)(2), HA). To achieve better biocompatibility with bone, metal implants made of Ti-6Al-4V are often coated with bioceramics. Dip-coating techniques scarcely are used to apply HA onto metallic implants. New dipping-solution recipes to be used for HA coatings are described in this work. Scanning electron microscopy and X-ray d...
Fatigue behavior of Ti-6Al-4V foams processed by magnesium space holder technique
Asik, E. Erkan; Bor, Sakir (2015-01-05)
Porous Ti-6Al-4V alloys are widely used in the biomedical applications for hard tissue implantation due to their elastic moduli being close to that of bone. In this study, porous Ti-6Al-4V alloys were produced with a powder metallurgical process, space holder technique, where magnesium powders were utilized to generate porosity in the range of 51-65 vol%. The production of porous Ti-6Al-4V alloys was composed of three steps. Firstly, spherical Ti-6Al-4V powders with an average size of 55 mu m were mixed wit...
Stem Cell and Advanced Nano Bioceramic Interactions
Kose, Sevil; Kankilic, Berna; Gizer, Merve; Dede, Eda Ciftci; Bayramlı, Erdal; KORKUSUZ, PETEK; KORKUSUZ, FEZA (2018-01-01)
Bioceramics are type of biomaterials generally used for orthopaedic applications due to their similar structure with bone. Especially regarding to their osteoinductivity and osteoconductivity, they are used as biodegradable scaffolds for bone regeneration along with mesenchymal stem cells. Since chemical properties of bioceramics are important for regeneration of tissue, physical properties are also important for cell proliferation. In this respect, several different manufacturing methods are used for manuf...
Citation Formats
B. YILMAZ, A. Z. G. ALSHEMARY, and Z. Evis, “Co-doped hydroxyapatites as potential materials for biomedical applications,” MICROCHEMICAL JOURNAL, pp. 443–453, 2019, Accessed: 00, 2020. [Online]. Available: