Physicochemical Characterization of Europium-Doped Hydroxyapatite Thin Films with Antifungal Activity

Abstract

Owing to its unique biological and physicochemical properties, hydroxyapatite (HAp) represents one of the most extensively studied biomaterials for biomedical applications. It is well known that Candida is currently one of the fungi frequently involved in the onset and development of post-implant infections and, owing to the appearance of antifungal resistance, it is quite difficult to treat despite all the tremendous efforts made in this regard by the scientific world. Therefore, in this context, we report for the first time in this paper, the development and characterization of europium-doped thin films (5EuHAp, xEu = 0.05) on a Si substrate by a spin-coating method. The results of ultrasound (US), zeta (ζ) potential, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) studies are presented. The XRD studies conducted on 5EuHAp suspension revealed the nanometric dimensions of the particles and sample purity. In addition, a moderate stability of the 5EuHAp suspension was observed. XPS measurements revealed the presence of Eu 3d in the 5EuHAp thin films. In the SEM micrographs, the surface uniformity and the absence of the surface defects could be observed. Moreover, the results of the FTIR studies showed the presence of the vibrational bands specific to the HAp structure in the studied sample. The antifungal activity of the HAp and 5EuHAp suspensions and coatings was evaluated using the Candida albicans ATCC 10231 (C. albicans) fungal strain. The qualitative assays of the antifungal properties of HAp and 5EuHAp coatings were also visualized by SEM and CLSM. The antifungal studies revealed that both 5EuHAp suspensions and coatings exhibited noticeable antifungal activity against C. albicans cells.

Lanthanides-Substituted Hydroxyapatite for Biomedical Applications

“…MG63 seeded onto Eu-HAp discs made with samples with Eu/(Eu + Ca) between 0.5% and 1.5% did not show changes in proliferation when compared to the control [ 117 ]. In agreement with these results, Ciobanu et al observed good viability of the osteoblastic cell line with a higher Eu concentration [ 116 ]. Liu et al described a good viability of BMSCs after 1, 3, 5 and 7 days of incubations with Eu-HAp NPs (concentrations from 3.125 µg/mL to 12.5 µg/mL).…”

“…The antifungal effect against C. albicans was demonstrated with 2 and 5 at. % Eu values [ 59 , 116 ]. In the last case, the adherence development of fungal biofilm after 24 h of incubation was inhibited.…”

“…In the last case, the adherence development of fungal biofilm after 24 h of incubation was inhibited. In addition, both the suspension of NPs and the thin films caused a significant reduction in CFUs [ 116 ].…”

Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L

“…Many studies have demonstrated the improvement of cellular response thanks to this material's high biocompatibility and enhanced protection against corrosion phenomena [48][49][50]. Moreover, it has been demonstrated that the biological and physicochemical properties of hydroxyapatite can be increased by doping it with various ions such as iron [51], magnesium [52], europium [53], samarium [54], silver [55], and cerium [56].…”