Preparation and Characterizations of Dispersible Fluorinated Hydroxyapatite Nanoparticles with Weak Antibacterial Activity

Abstract

To develop a nanoscaled coating material for medical devices possessing weak antibacterial activity, dispersible and crystalline fluorinated hydroxyapatite (F-HAp) nanoparticles were prepared using antisintering agent to avoid calcination-induced sintering. The product was identical to fluorapatite, as determined by X-ray diffraction and Fourier transform infrared spectroscopy. The primary particles generally showed rod-shaped morphology with a length of 367 ± 67 nm and a width of 223 ± 21 nm measured by scanning electron microscopy (SEM). The dispersed average particle size (313 ± 51 nm) in ethanol analyzed by dynamic light scattering was almost the same as that obtained from the SEM images. In the evaluation of solubility in acidic aqueous solution, F-HAp and original hydroxyapatite (HAp) nanoparticles started to dissolve at around pH 3.4 and 4.2, respectively. Thus, the stability of F-HAp in a living body increased compared with original HAp. The antibacterial activity of F-HAp nanoparticles was higher than that of fluoride in sodium fluoride alone or the original HAp nanoparticles. However, it was estimated that the effect of F-HAp was much lower compared with that of silver, one of the popular antibacterial materials. Thus, the dispersed F-HAp nanoparticles possessing weak antimicrobial activity can be useful without severe damage to the living tissue.

Facile biogenic fabrication of hydroxyapatite nanorods using cuttlefish bone and their bactericidal and biocompatibility study

“…The formation of a biofilm (bacterial colonies) on Hap is one of the major causes of implant failure, therefore it is essential to study their bactericidal property. It can be noted from the literature that nanometer-sized Hap can effectively inhibit antibacterial activity but only when doped or cationic-substituted [55,56]. In contrast, the CB-derived Hap nanorods in the present study show optimum bactericidal effect on E. coli and S. aureus due to the size (>50 nm) and morphology of the material.…”

Continuous antimicrobial mechanism of dispersible hydroxyapatite nanoparticles doped with zinc ions for percutaneous device coatings

“…Antimicrobial activities of Zn-HAp nanoparticles-coated sheets were evaluated according to our previous report. 23 Briefly, Escherichia coli (E. coli) K-12 W3110 and Staphylococcus aureus 209P ( S. aureus) cells were cultivated in Luria-Bertani (LB) medium (1% tryptone, 1% NaCl, and 0.5% yeast extract) at 37°C for 24 h. After dilution of cell cultures with 140 mM NaCl to adjust optical density at 600 nm (OD 600 ) to 0.01, 100 μL of the cell suspension were poured onto the coated sheets and incubated at 25°C for 1 h. A 10-fold dilution series of the cells was prepared and 5 μL of each diluted sample were cultured on LB agar (LB broth with 1.5% agar) at 37°C for 15 h. For the evaluation of antibacterial retaining activity of Zn-HAp nanoparticles, the nanoparticles were initially soaked in PBS at 37°C for 2 weeks and dried at 60°C for 24 h. One mg of the soaked Zn-HAp nanoparticles in 100 μL NaCl-solution was added to E. coli suspensions (OD 600 = 0.01), and incubated at 25°C for 1 h. The numbers of viable cells were counted using the same method for the Zn-HAp coated sheets, as described above. This work was fully approved by the Kindai University Biosafety Committee and was conducted in accordance with regulation on the use of pathogens.…”

Shareability of antibacterial and osteoblastic‐proliferation activities of zinc‐doped hydroxyapatite nanoparticles in vitro

“…14,15 Moreover, ions (silver, fluoride, or titanium)-doped HAp nanoparticles were also prepared by the method. [16][17][18][19][20] In particular, the antibacterial activities of ion-doped HAp nanoparticles were evaluated against several types of pathogenic microorganisms.…”