Formation Of nHAp Research Articles

Facile mussel-inspired polymerization to facilitate biomimetic in situ homogeneous mineralization for bone regeneration

As a mussel-inspired polymer, polydopamine (PDA) coating can be used as a simple and universal way to form nano-hydroxyapatite (nHAP) crystals on a variety of substrates. Therefore, PDA is widely used in the preparation of bone repair materials. However, its uneven distribution and easy degradation under strongly alkaline conditions limit its application. Therefore, based on the principle of in situ regeneration, this study combined the freeze-drying technology with the diffusion method of ammonium carbonate to bionics construct porous micro-nano composite scaffolds. Chitosan (CS) and dopamine hydrochloride (DA) were used as the chief components to form a multilayer layered scaffold structure. PDA and nHAP grow in situ on the surface of the freeze-dried scaffolds after ammonium carbonate gas diffusion treatment and Tris buffer immersion. The mild synthesis method effectively avoided the decomposition of PDA, and the gas diffusion method promoted the uniform distribution of PDA. The effect of PDA on nHAP formation was studied by adjusting the amount of DA. The cross-linking reaction between PDA and CS was verified by FTIR and XPS. Surface morphology was observed by SEM. The formation of nHAP was confirmed by XRD. The scaffolds had good porosity, degradation, water absorption, thermal stability and biomimetic mineralization properties. Cell experiments showed that the scaffolds had good biocompatibility and had no toxicity to cells. The construction of bone defect animal model further verified that the scaffolds promoted bone regeneration in the defect site of the body. This study provided a new idea and method for the preparation of bone repair scaffolds.

Structural and morphological analysis of zinc incorporated non-stoichiometric hydroxyapatite nano powders

In this study, Zn incorporated non-stoichiometric hydroxyapatite (nHAp) was synthesized via precipitation method and effect of the incorporation of Zn (fraction: 2, 4, 6 and 8 mol-%) on the microstructure of nHAp was studied by XRD, FTIR analysis and SEM-EDS techniques. The formation of nHAp was confirmed by XRD and FTIR those showed that no secondary phase was formed through the Zn incorporation. The SEM studies also revealed that particles were formed in nano-metric size (30-60 nm). It was found that crystallite and particle size of Zn incorporated nHAp gradually decreased up to 6 mol-%, and started to increase while the Zn fraction reached up to the 8 mol-% and hence the morphology of the aggregated products was also changed. It can be concluded that the incorporation of Zn cations cause to form nHAp phase. Furthermore, the nHAp microstructure has deviated from stoichiometric condition by incorporation of more Zn cations.

Hydroxyapatite - starch nano biocomposites synthesis and characterization

Bone like hydroxyapatite (nHAp) was synthesized via an in situ biomimetic process in presence of wheat starch. The effect of polymer concentration alteration on the final structure of nHAp was investigated. Formation of the nHAp at room temperature was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Size and morphology of the nHAp samples were characterized using scanning and transmission electron microscopy (SEM and TEM). Starch as a template agent has influence on shape of the HAp precipitated in its aqueous solution. It leads to formation of rode like nHAp which is similar to this inorganic component in natural bone.