Hydroxylapatite nanoparticles: fabrication methods and medical applications

Abstract

Hydroxylapatite (or hydroxyapatite, HAp) exhibits excellent biocompatibility with various kinds of cells and tissues, making it an ideal candidate for tissue engineering, orthopedic and dental applications. Nanosized materials offer improved performances compared with conventional materials due to their large surface-to-volume ratios. This review summarizes existing knowledge and recent progress in fabrication methods of nanosized (or nanostructured) HAp particles, as well as their recent applications in medical and dental fields. In section 1, we provide a brief overview of HAp and nanoparticles. In section 2, fabrication methods of HAp nanoparticles are described based on the particle formation mechanisms. Recent applications of HAp nanoparticles are summarized in section 3. The future perspectives in this active research area are given in section 4.

Thermal treatment effect on structural features of mechano-synthesized fluorapatite-titania nanocomposite: A comparative study

“…This result is in good agreement with previous studies that have shown polymeric vial along with zirconia balls is an appropriate milling media to annihilate contamination problems and to achieve modified morphologies with high biomedical performance [17,25,28]. Figure 3 shows the XRD profile and schematic view of CaHPO 4 , Ca(OH) 2 and CaF 2 powder mixture in the presence of 20 wt% TiO 2 after the beginning of milling.…”

“…From Fig. 4(a), all the sharp characteristic peaks corresponding to Ca(OH) 2 and CaF 2 disappear completely after 5 h of milling. Also several characteristic peaks corresponding to CaHPO 4 vanish and a number of new broadened peaks belonging to FAp emerge especially between 2θ = 31°-34°.…”

“…In the field of biomaterials, hydroxyapatite (HAp, Ca 10 (PO 4 ) 6 (OH) 2 ) is one of the most frequent forms of bioceramics in biological organisms which shows excellent biocompatibility with various kinds of cells and tissues [2]. The close chemical similarity of HAp to natural bone has led to the extensive research efforts to use synthetic HAp (s-HAp) as a bone substitute and/or replacement in biomedical applications [3].…”

“…One of the best methods to modify HAp is substitution of OH − groups by several anions like OH − , F − , Cl − , Br − , O 2− and CO 4 2− [2]. In the presence of F − group, this modification leads to the formation of fluorine-substituted HAp (FHAp, Ca 10 (PO 4 ) 6 (OH) 2x F x , 0 ≤ x ≤ 1) which causes an increase in crystallinity degree, a decrease in crystal strain and a rise in thermal stability [13].…”

“…In all the samples, the weight ratio of ball-to-powder (BPR), total powder mass and rotational speed were 20:1, 6 g and 600 rpm, respectively. To produce FAp-TiO 2 composite nanopowders (reaction (1)), a mixture of CaHPO 4 , Ca(OH) 2 and CaF 2 was mixed with a certain amount of titania (20 wt%) and then was mechanically activated for 5 h, 10 h and 15 h respectively without using any process control agent (PCA). 6CaHPO 4 + 3Ca(OH) 2 + CaF 2 + TiO 2 → Ca 10 (PO 4 ) 6 F 2 +TiO 2 + 6H 2 O (1) To evaluate the influence of thermal treatment on the structural evolution, all the milled specimens were filled in a quartz boat separately, and then were annealed under atmospheric pressure at 700 ℃ for 2 h. In the thermal cycle, the heating rate from room temperature up to the desired temperature was fixed at 10 ℃/min.…”