Anti-inflammatory and antimicrobial activity of bioactive hydroxyapatite/silver nanocomposites

Abstract

Biomaterials are often used in orthopedic surgery like cavity fillings. However, related complications often require long-term systemic antibiotics, device removal, and extended rehabilitation. Hydroxyapatite/silver (HA/Ag) composites have been proposed as implantation biomaterials owing to the osteogenic properties of hydroxyapatite and to the antimicrobial efficiency of silver. Nevertheless, higher silver concentrations induce cytotoxic effects. The aim of this study was to synthesize and characterize HA/Ag nanocomposites that will allow us to use lower concentrations of silver nanoparticles with better antimicrobial efficiency and anti-inflammatory properties. The characterization of HA/Ag was performed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, and laser diffraction. Bioactivity was evaluated under a simulated body fluid. The viability of osteoblast like-cells (MG-63) was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) and the antimicrobial activity was evaluated by the standard McFarland method. The detection of nitric oxide was measured by a colorimetric assay and the inflammatory cytokines by flow cytometry. We obtained particulate composites of calcium phosphates identified as hydroxyapatite and silver nanoparticles. The bioactivity of the HA/Ag nanocomposites on SFB was confirmed by apatite formations. The viability of MG-63 cells was not affected. We also found antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans owing to the presence of silver nanoparticles at non-cytotoxic concentrations. HA/Ag reduced the release of nitric oxide and decreased the secretion of IL-1 and TNF-α in cells stimulated with Lipopolysaccharide (LPS). In conclusion, the inflammatory and antimicrobial capacity of the HA/Ag nanocomposites, as well as its bioactivity and low cytotoxicity make it a candidate as an implantation biomaterial for bone tissues engineering and clinical practices in orthopedic, oral and maxillofacial surgery.

Modulation of bone turnover aberration: A target for management of primary osteoporosis in experimental rat model

“…Also, the increase in oxidative stress promotes the syntheses of pro-inflammatory molecules (IL-1, IL-6 and TNF-α) which trigger bone damage and enhance osteoclastic activity, thus disturbing the bone remodelling balance [108]. It has been reported that silver hydroxyapatite nanoparticles attenuate the inflammatory effect by decreasing the syntheses of the pro-inflammatory mediators like TNF-α and IL-1 [109]. Nakayama et al [110] found that TNF-α stimulated BSP mRNA expression at three hours of incubation with Saos2 osteoblast-like cells.…”

“…Finally, in the current work, the femur bone from osteoporotic rats administered nAg/HA showed a higher intensity of colour representing the alizarin red S staining in comparison with the osteoporotic rats. Martínez-Sanmiguel et al [109] stated that silver/hydroxyapatite nanoparticles have the ability to promote mineralisation/apatite nucleation in vitro.…”

Preparation of a New Biocomposite Designed for Cartilage Grafting with Antibiofilm Activity

“…Silver has well-documented antibacterial activity. However, the bactericidal properties of silver-doped apatites are still tested to find the best structure . Thus, the antibacterial activity of fluor- and hydroxyapatites doped with Ag + (1.0, 2.5, and 5.0 mol%) was investigated using bacterial strains commonly applied for drug susceptibility testing.…”

“…48 The results also showed good antibacterial activity against P. aeruginosa and E. coli, which is consistent with the previous findings. 47,49 3.7. Antibiofilm Activity.…”

Tumor necrosis factor-α and osterix expression after the transplantation of a hydroxyapatite scaffold from crab shell (Portunus pelagicus) in the post-extraction socket of Cavia cobaya

“…As demonstrated in previous studies, which used a combination of HA and silver to reduce the release of nitric oxide and decrease the secretion of IL-1 and TNF-α in cells that were stimulated with Lipopolysaccharide (LPS), LPS stimulates monocytes/ macrophages through TLR4, resulting in the activation of a series of signalling events that potentiate the production of inflammatory mediators. 22,23 There is a correlation between the particle size of HA and the secretion of TNF-α. A previous study showed that a smaller HA particle size (especially a diameter of 1-2 µm and a pore size of 10-50Å) stimulates a higher macrophage TNF-α secretion.…”