Preparation and Adsorption Properties of Hydroxyapatite Surface-Modified by Cetylphosphate

Abstract

Hydroxyapatite (HAP) was prepared from CaCl 2 , Na 2 HPO 4 and NaOH in an aqueous phase mixed with a chloroform solution of cetylphosphate (CP). The CP was incorporated mainly on the surface of HAP but not to its bulk phase, resulting in formation of a hydrophobic surface. This surface-modified HAP has various characteristic properties different from those of the intact HAP. Some of the examples are as follows; an increase in a contact angle of water droplet, a decrease in a mean diameter of the HAP particle, and increases in the amounts of adsorption of various organic compounds. The aim of this study was of characterization of the surface-modified HAP through determining the adsorption amounts of various organic compounds on the surface. As for the adsorption of a surfactant to the modified HAP, it was concluded that hydrophobic interaction between alkyl chains of a surfactant and those of CP implanted on the surface became more important than hydrophilic interaction between polar/ionic groups of a surfactant and ions exposed on the intact area of the HAP. In the adsorption of bovine serum albumin (BSA), it was denatured by the CP implanted on the surface of the modified HAP (i.e., surface denaturation). Adsorption properties of the surface-modified HAP were quite different from those of the intact HAP.

Fabrication of Electrospun PLA-nHAp Nanocomposite for Sustained Drug Release in Dental and Orthopedic Applications

“…The change of pH pattern in deionized water can be explained in terms of a high affinity of nHAp for water [ 31 ]. In water, the hydrolysis of nHAp predominates causes an increase in pH, and might have initially restricted the hydrolysis of PLA [ 32 ].…”

Characterization of a composite polylactic acid-hydroxyapatite 3D-printing filament for bone-regeneration

“…Taking PLA as a structural biocompatible (and mostly bioinert) base for a composite, hydroxyapatite (HAp) was selected as a potential bone-regenerating functionalisation agent. HAp offers micro-scale particulates and thermal-stability at the processing temperatures of PLA 3D-printing filament extrusion and FFF, a consistent affinity for organic molecules, and documented osteoconductive properties [6,[46][47][48][49][50]. The current study will present results from the development for a method for thorough integration of HAp particles into a PLA matrix in the form of a 3D-printable filament.…”

Design and Synthesis of Hydroxyapatite with Organic Modifiers for Application to Environmental Remediation

“…HAP modified with cetylphosphate revealed that the higher the initial concentration of CP in a chloroform solution, and the higher the surface concentration of CP on HAP, the greater the contact angle of water [31]. This means that water droplets had difficulty spreading on the particle and would minimize their contact with the surface of the CPmodified HAP due to the hydrophobic tails of the CP on the CP-HAP surface.…”

“…The resulting CP-mHAP has a hydrophobic surface and a decrease in particle diameter [31]. This modification also increased the surface adsorption for organic compounds such as sodium p-dodecylbenzenesulfonate (SDBS) because of an interaction between the alkyl chains of SDBS and the CP-modified HAP surface [31].…”

“…The specific surface area, however, increased as the CP concentration increased. Sodium dodecylbenzenesulfonate (SDBS) adsorbed onto CP-HAP due to a hydrophobic interaction of the alkyl chains [31].…”