Structural and physical properties of antibacterial Ag-doped nano-hydroxyapatite synthesized at 100°C

Abstract

Synthesis of nanosized particle of Ag-doped hydroxyapatite with antibacterial properties is in the great interest in the development of new biomedical applications. In this article, we propose a method for synthesized the Ag-doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionized water. Other phase or impurities were not observed. Silver-doped hydroxyapatite nanoparticles (Ag:HAp) were performed by setting the atomic ratio of Ag/[Ag + Ca] at 20% and [Ca + Ag]/P as 1.67. The X-ray diffraction studies demonstrate that powders made by co-precipitation at 100°C exhibit the apatite characteristics with good crystal structure and no new phase or impurity is found. The scanning electron microscopy (SEM) observations suggest that these materials present a little different morphology, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O), and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) analysis. FT-IR and FT-Raman spectroscopies revealed that the presence of the various vibrational modes corresponds to phosphates and hydroxyl groups. The strain of Staphylococcus aureus was used to evaluate the antibacterial activity of the Ca10-xAgx(PO4)6(OH)2 (x = 0 and 0.2). In vitro bacterial adhesion study indicated a significant difference between HAp (x = 0) and Ag:HAp (x = 0.2). The Ag:Hap nanopowder showed higher inhibition.

Figure 1

Comparative representation of the experimental XRD patterns of the Ca_10-xAg_x(PO₄)₆(OH)₂ samples synthesized xAg = 0 (HAp) and xAg = 0.2 (Ag:HAp), and the characteristic lines of hydroxyapatite according to the ICDD-PDF number 9-432.

Figure 2

TEM images of the Ca_10-xAg_x(PO₄)₆(OH)₂ samples with xAg = 0 (HAp) and xAg = 0.2 (Ag:HAp).

Figure 3

SEM images of the Ca_10-xAg_x(PO₄)₆(OH)₂ samples with xAg = 0 (HAp) and xAg = 0.2 (Ag:HAp).

Figure 4

EDAX spectrum of the Ag:HAp samples and simultaneous distributions of individual elements based on selected region of the sample.

Figure 5

XPS general spectrum of Ca_10-xAg_x(PO₄)₆(OH)₂, (x_Ag = 0.2) powder (A). XPS narrow scan spectra for Ag (B).

Figure 6

Transmittance infrared spectra of the Ca_10-xAg_x(PO₄)₆(OH)₂ samples with xAg = 0 (HAp) and xAg = 0.2 (Ag:HAp).

Figure 7

FT-Raman spectra of the Ca_10-xAg_x(PO₄)₆(OH)₂ samples with x = 0 (HAp) and x = 0.2 (Ag:HAp).

Figure 8

Adherence of Staphylococcus aureus on different concentrations of Ca_10-xAg_x(PO₄)₆(OH)₂ (x = 0 and 0.2) nanopowders.