Obtention and characterization of nano bio-hydroxyapatite particles by combined hydrothermal alkaline and ultrasonic wet milling methods

Abstract

This article deals with the extraction, recovery, and characterization of nano bio-hydroxyapatite particles (nBio-HAp) from pig bones obtained by hydrothermal alkaline treatment in combination with an ultrasonic wet milling process. Pig bone powder was defatted and deproteinized with an 1 N potassium hydroxide (KOH) aqueous solution for 24 h with stirring at 90 °C, followed by ultrasonic treatment pulsed at 100 W (Pulse-cycle: 70%) for 10, 20, 30, and 60 min. Fourier Transform Infrared spectroscopy (FT-IR) showed that the alkaline treatment removed the organic compounds from the mineral matrix. Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) showed that the particle size decreased with increasing duration of ultrasound, indicating the mechanism of erosion and fragmentation of micro agglomerates into nanoparticles. The X-ray patterns showed that none of the methods used to clean and extract the nanoparticles (ultrasound) damaged the Bio-HAp nanocrystals. Full Width at Half Maximum (FWHM) and crystallite size proved that they have a size between 22 and 27 nm, which was confirmed by Transmission Electron Microscopy (TEM) in the form of platelets and bacilli. Inductively coupled plasma (ICP) showed the presence of Mg, Na, K, and Zn as minority ions and that the isolation processes of Bio-HAp nanoparticles do not affect their trace element concentrations.