Synthesis, Characterization, and Antimicrobial Activity of Magnesium-Doped Hydroxyapatite Suspensions

Abstract

Obtaining nanoscale materials has allowed for the miniaturization of components, which has led to the possibility of achieving more efficient devices with faster functions and much lower costs. While hydroxyapatite [HAp, Ca10(PO4)6(OH)2] is considered the most widely used material for medical applications in orthopedics, dentistry, and general surgery, the magnesium (Mg) is viewed as a promising biodegradable and biocompatible implant material. Furthermore, Mg is regarded as a strong candidate for developing medical implants due to its biocompatibility and antimicrobial properties against gram-positive and gram-negative bacteria. For this study, magnesium-doped hydroxyapatite (Ca10−xMgx (PO4)6 (OH)2, xMg = 0.1), 10MgHAp, suspensions were successfully obtained by an adapted and simple chemical co-precipitation method. The information regarding the stability of the nanosized 10MgHAp particles suspension obtained by ζ-potential analysis were confirmed for the first time by a non-destructive ultrasound-based technique. Structural and morphological studies of synthesized 10MgHAp were conducted by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode and scanning electron microscopy (SEM). The XRD analysis of the 10MgHAp samples confirmed that a single crystalline phase associated to HAp with an average grain size about 93.3 nm was obtained. The FTIR-ATR spectra revealed that the 10MgHAp sample presented broader IR bands with less visible peaks when compared to a well-crystallized pure HAp. The SEM results evidenced uniform MgHAp nanoparticles with spherical shape. The antimicrobial activity of the 10MgHAp suspension against gram-positive strains (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212), gram-negative strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), as well as a fungal strain (Candida albicans ATCC 90029) were evaluated.

Silver-Doped Hydroxyapatite Thin Layers Obtained by Sol-Gel Spin Coating Procedure

“…The results obtained in this study are in accord with previously reported studies regarding the potential antimicrobial properties of materials and composite layers based on hydroxyapatite enhanced with various antimicrobial agents, such as metal ions, that are known to possess antimicrobial properties [36][37][38]. Despite the progress made in the biomedical filed, several studies have reported that the development of implant-related infection is still of great concern and that C. albicans can easily colonize and aggregate on prostheses and implants [39][40][41].…”

“…Thus, by placing in an ultrasonic bath the final gel for 12 h, its stability increased. The results presented in this study were sustained by previously reported studies [36][37][38], which state that hydroxyapatite could be enriched with various metal ions in order to exhibit antimicrobial properties. Nonetheless, this study emphasizes for the first time the obtaining of stable AgHAp solutions with antimicrobial properties, using an adapted synthesis method, for the development of new and improved coatings on the basis of silver-doped hydroxyapatite.…”

Dextran-Thyme Magnesium-Doped Hydroxyapatite Composite Antimicrobial Coatings

“…The antimicrobial properties of thyme EO have been previously reported against a pathogenic and/or spoilage food-related bacterium [26,27], as well as against common bacterial strains, such as Staphylococcus aureus and Listeria monocytogenes [23]. Nonetheless, there are several emerging cations with both antimicrobial properties and important roles in the enhancement of the biological interactions of HAp with the surrounding tissues, amid which Mg 2+ comes into prominence [28][29][30]. Magnesium is one of the most important essential trace elements, being involved in the development of bones and connective tissues and possessing osteogenic and angiogenic stimulating properties, demonstrated both in vitro and in vivo [31][32][33][34][35].…”

“…In a previous study [30], the authors explored the stability of Mg-doped HAp (Ca 10-x Mg x (PO 4 ) 6 (OH) 2 , x Mg = 0.1) suspensions, which were characterized by remarkable biocompatibility and antimicrobial efficacy against Pseudomonas aeruginosa, S. aureus, and Candida albicans microbial strains. The coupling of Mg doping and thyme EO antibacterial agents within a nano-HAp milieu might yield improved biofunctional properties.…”

Ozonized Gel Against Four Candida Species: A Pilot Study and Clinical Perspectives

“…A better osseointegration process in endosseous implants treated with photobiomodulation and ozone therapy has been described [26]. Modifications have been proposed to improve their integration but also to confer anti-infective properties [27][28][29]. Ozone-ultraviolet treatment of orthopedic titanium implants improved bone-implant osseointegration.…”