Synthesis of spherical hydroxyapatite granules with interconnected pore channels using camphene emulsion

Abstract

The aim of this study was to fabricate porous spherical hydroxyapatite (HA) granules with interconnected pore channels for use as a bone graft substitute. Various weights of camphene porogen were mixed with nano-sized HA powder (camphene/HA = 0, 10, 30, 50, 70, and 90% w/w) and 10% gelatin aqueous solution then added to the mixture. The water-in-oil emulsion method was employed to obtain spherical-shaped granules, of which those 1000-2000 μm in diameter were selectively classified using a standard sieve set. Thermogravimetric analysis and X-ray diffraction were used to determine optimal sintering conditions. The sintered granules were characterized using field emission-scanning electron microscopy (FE-SEM), microcomputed tomography, and porosimetry. The pore size and porosity of spherical HA granules increased with the addition of camphene. Granules with a HA/camphene ratio of 90% (HG90) demonstrated macropores (>50 μm) with interconnected pore channels (porosity: 58.49%). In addition, FE-SEM examination of HG90 coated with polycaprolactone showed that the granule may hold promise as a drug delivery carrier. We concluded that these HG90 granules merit consideration as a bone graft substitute or drug delivery carrier in bone tissue engineering.

Synthesis of spherical calcium phosphate particles for dental and orthopedic applications

“…Unfortunately, this approach can only work with fairly large spheres (several millimeters in diameter) and CaP phases stable at high temperature (e.g., β-TCP, HA). Similar granule sizes and macropore dimensions were obtained by Lee and Park 76 using double emulsions and by Yang et al 78 using drip casting. At a much lower scale, ≈100nm hollow apatite particles can be obtained by precipitation either without 112 - 114 , 125 or with templates 118 , 128 .…”

“… Figure 5. hierarchical structures obtained using different methods: (A) emulsification (Scale bar: 300µm), 81 (B) drip-casting (50µm) 70 ; (C) lost-wax method (3mm) 84 ; (D) precipitation (50µm) 129 ; and (E) emulsification (sphere diameter ≈1.5mm) 78 . With the exception of (D) (OCP), all particles consist of an apatite (images reproduced with the permission of the authors).…”

Fabrication and characterization of novel porous titanium microspheres for biomedical applications

“…0.2 g of gelatin was added into 1.8 ml of deionized water. Using optimal concentration of gelatin can help produce a spherical form of Ti microsphere [19]. The mixture was vigorously stirred and then mixed with the above-mentioned mixture of camphene/Ti.…”

Dual response of osteoblast activity and antibacterial properties of polarized strontium substituted hydroxyapatite—Barium strontium titanate composites with controlled strontium substitution

“…Hydroxyapatite (HA) has extensively been used in medical implants and filler materials, such as, granules, microspheres, and scaffolds, 1‐6 while its combination with piezoelectric materials is yet to be fully established as a biomedical material despite efforts in this area 7 . As an example, researchers have shown considerable osteoblast attachment on polarized calcium phosphate‐piezoelectric composites by inducing permanent charge on its surface 8 .…”