Hierarchically nanostructured hydroxyapatite: hydrothermal synthesis, morphology control, growth mechanism, and biological activity

Abstract

Hierarchically nanosized hydroxyapatite (HA) with flower-like structure assembled from nanosheets consisting of nanorod building blocks was successfully synthesized by using CaCl 2 , NaH 2 PO 4 , and potassium sodium tartrate via a hydrothermal method at 200°C for 24 hours. The effects of heating time and heating temperature on the products were investigated. As a chelating ligand and template molecule, the potassium sodium tartrate plays a key role in the formation of hierarchically nanostructured HA. On the basis of experimental results, a possible mechanism based on soft-template and self-assembly was proposed for the formation and growth of the hierarchically nanostructured HA. Cytotoxicity experiments indicated that the hierarchically nanostructured HA had good biocompatibility. It was shown by in-vitro experiments that mesenchymal stem cells could attach to the hierarchically nanostructured HA after being cultured for 48 hours. Objective: The purpose of this study was to develop facile and effective methods for the synthesis of novel hydroxyapatite (HA) with hierarchical nanostructures assembled from independent and discrete nanobuilding blocks. Methods: A simple hydrothermal approach was applied to synthesize HA by using CaCl 2 , NaH 2 PO 4 , and potassium sodium tartrate at 200°C for 24 hours. The cell cytotoxicity of the hierarchically nanostructured HA was tested by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Results: HA displayed the flower-like structure assembled from nanosheets consisting of nanorod building blocks. The potassium sodium tartrate was used as a chelating ligand, inducing the formation and self-assembly of HA nanorods. The heating time and heating temperature influenced the aggregation and morphology of HA. The cell viability did not decrease with the increasing concentration of hierarchically nanostructured HA added. Conclusion: A novel, simple and reliable hydrothermal route had been developed for the synthesis of hierarchically nanosized HA with flower-like structure assembled from nanosheets consisting of nanorod building blocks. The HA with the hierarchical nanostructure was formed via a soft-template assisted self-assembly mechanism. The hierarchically nanostructured HA has a good biocompatibility and essentially no in-vitro cytotoxicity.

Organic–inorganic collagen/iota‐carrageenan/hydroxyapatite hybrid membranes are bioactive materials for bone regeneration

“…Hybrid membrane exposure to SBF (Supporting Information 5) gives rise to elongated needle‐like and flower‐like microparticles that form porous hollow HAp spheres, which corroborates with the morphology described for this mineral . These observations also attest to membrane bioactivity, confirming the FT‐IR and XRD analyses.…”

Insight into Biological Apatite: Physiochemical Properties and Preparation Approaches

“…Hydrothermal hydrolysis is a common method used for the synthesis of HAp [69–72]. However, it was less often used in the preparation of biological apatite.…”

Biodegradable and Biocompatible Systems Based on Hydroxyapatite Nanoparticles

“…Despite the high simplicity of nanoprecipitation, a great control over morphology and size can be achieved by modification of experimental conditions [24][25][26] and the addition of surfactants [27] (e.g., stearic acid, monosaccharides and cetyltrimethylammonium bromide (CTAB)) and chelating agents [28,29] (e.g., trisodium citrate and potassium sodium tartrate). Thus, the way reactants are mixed, the solvents that are employed or the pH conditions play a fundamental role on the final structure and morphology.…”