Synthesis and Optimization of Colloidal Hydroxyapatite Nanoparticles by Hydrothermal Processes

Abstract

This paper reports an optimized, simple, fast and inexpensive method for hydroxyapatite (HA) nanoparticle synthesis. Through a multivariate statistical analysis using a factorial design with 2 3 resolution, an empirical model was developed which allows control of the shape and size of the HA nanoparticles. This model was used to synthesize HA nanoparticles with sizes between 8 and 600 nm, formed by oriented attachment growth mechanism. The structure was confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images, which also showed that HA nanoparticles had well-defined nanorod forms and narrow size distributions. It was observed that the model is statistically significant and the main parameter for the growth of crystals in the hydrothermal process was temperature.

Dental Applications of Systems Based on Hydroxyapatite Nanoparticles—An Evidence-Based Update

“…Hydroxyapatite (HA) is currently used in clinical oral surgery, especially in bone tissue regeneration, such as for the treatment of periodontal bone defects, filling bone defects following cyst removal and apicoectomies, or, in the case of dental implant removal, to increase the width of atrophic alveolar ridges. Additionally, hydroxyapatite scaffolds are used in maxillofacial surgery to reconstruct parts of maxillary bones, or other parts of the facial skeleton, or even in pre-prosthetic surgery, in order to increase the width of the alveolar ridges [6,7].…”

“…HAnps can also prevent dental caries [16]; the particles can be introduced in toothpastes, where they will bond with both proteins and with fragments of plaque and bacteria, having the ability to act as a filler, repairing small defects on enamel surface [17]. Due to the high biocompatibility and bioactivity [17][18][19], as well as the antibacterial effect [20], hydroxyapatite nanoparticles have the ability to improve the properties of materials currently used in restorative dentistry [7,18].…”

“…HA nanoparticles obtained at 100 °C, over24 h, with the precursor concentrations of 0.1 mol/L −1 (TEM, scale bar value 50 nm) (D) HA nanoparticles obtained at 140 °C, over 48 h, with the precursor concentrations of 0.1 mol/L −1 (SEM, scale bar value 500 nm). Adapted from [7] under the terms of the Creative Commons CC BY license, accessed on 30 May 2021.…”

“…Regarding this aspect, Webster et al [27][28][29] proved that while these enhanced osteoblast functions refer to proliferation, alkaline phosphatase synthesis and calcium-containing mineral deposition, the size and topography and surface wettability of HAnps could promote increase in selective osteoblast adhesion (by increasing the adsorption of a protein-vitronectin-which mediates the osteoblast adhesion), and could also affect the conformations that enhance osteoblasts' functions. [7] under the terms of the Creative Commons CC BY license, accessed on 30 May 2021.…”