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    Fe3+/SeO42- dual doped nano hydroxyapatite: A novel material for biomedical applications
    (Wiley, 2018) Alshemary, Ammar Z.; Pazarceviren, Ahmet Engin; Tezcaner, Aysen; Evis, Zafer
    Dual ions substituted hydroxyapatite (HA) received attention from scientists and researchers in the biomedical field owing to their excellent biological properties. This paper presents a novel biomaterial, which holds potential for bone tissue applications. Herein, we have successfully incorporated ferric (Fe3+)/selenate ( SeO42-) ions into the HA structure (Ca10-x-yFey(PO4)(6-x)(SeO4)(x)(OH)(2-x-y)O-y) (Fe-SeHA) through a microwave refluxing process. The Fe-SeHA materials were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FESEM). XRD and FTIR analyses revealed that Fe-SeHA samples were phase pure at 900 degrees C. FESEM images showed that formation of rod-like shaped particles was inhibited dramatically with increasing Fe3+ amount. The Vickers hardness (HV) test showed that hardness values increased with increasing Fe3+ concentrations. Optical spectra of Fe-SeHA materials contained broadband over (200-600) nm. In vitro degradation and bioactivity tests were conducted in simulated body fluid (SBF). The incorporation of Fe3+/ SeO42- ions into the HA structure resulted in a remarkably higher degradation rate along with intense growth of apatite granules on the surface of the Fe-SeHA discs with Ca/P ratio of 1.35-1.47. In vitro protein adsorption assay was conducted in fetal bovine serum (FBS) and it was observed that the adsorption of serum proteins on Fe-SeHA samples significantly increased with increasing Fe3+ concentration. In vitro cytotoxicity tests were performed with human fetal osteoblast (hFOB) cell line and the results demonstrated that hFOB cells attached and proliferated faster on the Fe-SeHA materials compared to pure HA showing that Fe-SeHA materials were cytocompatible. ALP activity and intracellular calcium of hFOB cells on 1Fe-SeHA discs were statistically higher than pure HA, suggesting that presence of Fe3+ ion supported osteogenic differentiation of hFOB cells. Our results suggest that 1Fe-SeHA (0.2M Fe3+/0.5MSeO42- co-doped HA) material could be considered as a promising candidate material for orthopedic applications. (c) 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 340-352, 2018.
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    Porous clinoptilolite-nano biphasic calcium phosphate scaffolds loaded with human dental pulp stem cells for load bearing orthopedic applications
    (Iop Publishing Ltd, 2019) Alshemary, Ammar Z.; Pazarceviren, Ahmet Engin; Keskin, Dilek; Tezcaner, Aysen; Hussain, Rafaqat; Evis, Zafer
    Clinoptilolite (Cpt)-nanohydroxyapatite (HA) (Cpt-HA) scaffolds were fabricated as a potential material for load bearing orthopaedic applications. Cpt-HA materials were successfully synthesized by using microwave assisted reflux method followed by the fabrication of three-dimensional (3D) porous scaffold via thermal decomposition process using polyethylene glycol (PEG)/polyvinyl alcohol (PVA) as porogens. The scaffold materials were characterized using x-ray diffraction, Fourier transform Infra-red, Scanning electron microscopy and Energy dispersive spectroscopy techniques. Incorporation of Cpt in HA scaffold significantly increased the compressive strength and surface hardness while scaffolds retained an interconnected porous structure with 64% porosity. Human dental pulp stem cells (DPSCs) were isolated from the third molar and used as pluripotent-like cell model to evaluate the biological properties of Cpt-HA scaffolds. Highest cellular attachment and proliferation were observed for DPSCs seeded on 2.0 g Cpt-HA scaffolds compare to pure HA. Similarly, significantly higher ALP activity of cells was observed on Cpt-HA scaffolds compared to pure HA. The enhanced proliferation and osteogenic response of the DPSCs cultured on Cpt-HA scaffolds suggest that the fabricated scaffolds can be used in bone tissue engineering. In this work, we have successfully shown that the interconnected porous Cpt-HA scaffolds have superior mechanical biological properties compared to pure HA scaffold.