A brief review on hydroxyapatite production and use in biomedicine

Abstract

Hydroxyapatite (HAp) is a bioceramic widely studied due to its chemical similarity with the mineral component of bones. Besides, it is biocompatible, bioactive and thermodynamically stable in the body fluid what poses it as an attractive material for a wide range of applications in the biomedical field. Several efforts have been focused on the synthesis of particles of this material aiming to the precise control of size and morphology, porosity and surface area. HAp is widely used as an implant for bone tissue regeneration, as a coating for metallic implants and in a drug-controlled release. In this sense, the objective of this review is to gather information related to HAp, providing readers with information about synthesis methods, material characteristics and their applications.

Retardation effect of nanohydroxyapatite on the hydrolytic degradation of poly (lactic acid)

“…As can be seen in Figure 2, nHA hindered water diffusion into the sample, reducing the water available to promote the hydrolysis process. In addition, due to the alkaline nature of nHA, [29] this filler might have neutralized the catalytic effect of degradation by-products (carboxyl groups), reducing the hydrolysis process. [21] The degradation time required for a 20% weight loss for samples subjected to hydrolytic degradation at 37 C was estimated using the Arrhenius equation ( Table 2).…”

“…[3] The decrease in T g and T m occurs at longer times for the nHA-containing composites subjected to tests at 72 C, 60 C, and 48 C corroborating the weight loss and water uptake results, indicating that nHA may delay the hydrolytic degradation of PLA, since it acted as a water barrier and may have neutralized the catalytic effect of degradation byproducts due to its alkaline nature. [29] Figure 6 shows the percentage of crystallinity as a function of degradation time of PLA and PLA\nHA composites subjected to hydrolysis tests at 60 C. A significant increase in crystallinity was observed up to 28 days for all composites, followed by a decrease in crystallinity after 35 days. The percentage of crystallinity of PLA was higher compared to composites containing nHA.…”

Assessment of the Mechanical Properties of Orthopedic Screws Coated with Polyurethane Acrylate Containing Hydroxyapatite, Intended to Fix the Fragility Fractures

“…For this reason, fragility fractures fixation associate implants with the administration of drugs that stimulate bone recovery such as calcium, vitamin D, anti-resorption or anabolic agents [9.]. Lately, metallic or polymeric implants have been associated with hydroxyapatite (HA), which is a natural component found in bone [10,11]. Hydroxyapatite belongs to the calcium phosphates group.…”

A Brief Review on Biomedical Applications of Hydroxyapatite Use as Fillers in Polymer

“…Many studies have drawn great interest of hydroxyapatite because HA is widely used as biomedical material [6,7]. HA is a ceramic material with osteoconductive and biocompatibility properties similar to those of bones' mineral phase [4,[8][9][10][11][12]. HA can also enhance the growth of bones and assimilate with the surrounding bone tissues.…”

“…Experimental results have demonstrated the advantages of nano-HA in enamel repair [1,69]. Thus, HA has been incorporated in toothpastes and mouth-rinsing solutions to promote the restoration of demineralised enamel or dentin surfaces by depositing HA nanoparticles in the defects [11,72].…”