Evaluation of the Antimicrobial Activity of Different Antibiotics Enhanced with Silver-Doped Hydroxyapatite Thin Films.

Daniela Predoi,Cristina Liana Popa,Simona Liliana Iconaru,Patrick Chapon,Andreea Groza

doi:10.3390/ma9090778

Abstract

The inhibitory and antimicrobial effects of silver particles have been known since ancient times. In the last few years, a major health problem has arisen due to pathogenic bacteria resistance to antimicrobial agents. The antibacterial activities of new materials including hydroxyapatite (HAp), silver-doped hydroxyapatite (Ag:HAp) and various types of antibiotics such as tetracycline (T-HAp and T-Ag:HAp) or ciprofloxacin (C-HAp and C-Ag:HAp) have not been studied so far. In this study we reported, for the first time, the preparation and characterization of various thin films based on hydroxyapatite and silver-doped hydroxyapatite combined with tetracycline or ciprofloxacin. The structural and chemical characterization of hydroxyapatite and silver-doped hydroxyapatite thin films has been evaluated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The morphological studies of the HAp, Ag:HAp, T-HAp, T-Ag:HAp, C-HAp and C-Ag:HAp thin solid films were performed using scanning electron microscopy (SEM). In order to study the chemical composition of the coatings, energy dispersive X-ray analysis (EDX) and glow discharge optical emission spectroscopy (GDOES) measurements have been used, obtaining information on the distribution of the elements throughout the film. These studies have confirmed the purity of the prepared hydroxyapatite and silver-doped hydroxyapatite thin films obtained from composite targets containing Ca10−xAgx(PO4)6(OH)2 with xAg = 0 (HAp) and xAg = 0.2 (Ag:HAp). On the other hand, the major aim of this study was the evaluation of the antibacterial activities of ciprofloxacin and tetracycline in the presence of HAp and Ag:HAp thin layers against Staphylococcus aureus and Escherichia coli strains. The antibacterial activities of ciprofloxacin and tetracycline against Staphylococcus aureus and Escherichia coli test strains increased in the presence of HAp and Ag:HAp thin layers.

Highlights

With the development of bioengineering, new and improved biomaterials have been created and perfected in order to be used in different biomedical applications [1,2]
As revealed by the previous X-ray diffraction (XRD) analysis, silver and other impurities were not found in the Ag:HAp thin film. All these results demonstrated that silver ions have replaced calcium ions and the Ag:HAp thin film
The goal of this research was to study the structure, morphology and the antibacterial effect of different thin films based on hydroxyapatite, silver-doped hydroxyapatite and tetracycline/ciprofloxacin embedded in hydroxyapatite and silver-doped hydroxyapatite, respectively

Summary

Introduction

With the development of bioengineering, new and improved biomaterials have been created and perfected in order to be used in different biomedical applications [1,2]. Since synthetic hydroxyapatite has very low mechanical strength, it is usually used as a coating material for various metallic implants, facilitating osteointegration and increasing the success rate of orthopedic implants [11,12,13,14,15,16]. Researchers have discovered that different organic substances such as proteins or amino acids adsorbed on its surface transform it into an ideal environment for bacterial replication [5]. These bacteria give rise to post-surgical infection and may determine the formation of a biofilm [17]. A consequence of post-operatory infections is the necessity of additional surgeries and, in extreme cases, the removal of the implant [17]

Objectives

Methods

Findings

Discussion

Conclusion