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Additive manufacturing of biodegradable magnesium implants and scaffolds: Review of the recent advances and research trends
(Keai Publishing Ltd, 2021) Sezer, Nurettin; Evis, Zafer; Koc, Muammer
Synthetic grafting needs improvements to eliminate secondary surgeries for the removal of implants after healing of the defected tissues. Tissue scaffolds are engineered to serve as temporary templates, which support the affected tissue and gradually degrade through the healing period. Beside mechanical function to withstand the anatomic loading conditions, scaffolds should also provide a decent biological function for the diffusion of nutrients and oxygen to the cells, and excretion of the wastes from the cells to promote the new tissue growth and vascularization. Moreover, the degradation byproducts of the scaffolds should be safe to the human body. Development of such multifunctional scaffolds requires selection of the right material, design, and manufacturing method. Mg has been recognized as the prominent biodegradable metal with regards to its mechanical properties matching to that of human bone, degradability in the body fluid, and its ability to stimulate new tissue growth. Scaffolds with intricate porous structures can be designed according to the patient-specific anatomic data using computer aided designs. Additive manufacturing (AM) is the right method to materialize these models rapidly with reasonably acceptable range of dimensional accuracy. Thus, the recent research trend is to develop ideal scaffolds using biodegradable Mg through AM methods. This review compiles and discusses the available literature on the AM of biodegradable Mg parts from the viewpoints of material compositions, process conditions, formation quality, dimensional accuracy, microstructure, biodegradation, and mechanical properties. The current achievements are summarized together, and future research directions are identified to promote clinical applications of biodegradable Mg through the advancement of AM. (C) 2020 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.
Artificial neural network investigation of hardness and fracture toughness of hydroxylapatite
(Elsevier Sci Ltd, 2011) Evis, Zafer; Arcaklioglu, Erol
Hardness and fracture toughness of hydroxylapatite were investigated by artificial neural network (ANN). Hardness and fracture toughness of hydroxylapatite were predicted by using its sintering temperature, sintering time, relative density, and grain size with ANN. It was found that prediction results of its hardness and fracture toughness closely matched with the experimental results. (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Bactericidal and in vitro osteogenic activity of nano sized cobalt-doped silicate hydroxyapatite
(Elsevier Sci Ltd, 2022) Alshemary, Ammar Z.; Hussain, Rafaqat; Dalgic, Ali Deniz; Evis, Zafer
Hydroxyapatite (HA) particles with enhanced antibacterial properties can be prepared by integrating metal ions into the crystal structure of the nanoparticles. Cobalt and silicate ions containing HA (Co/Si-HA) with the formula Ca10-xCox(PO4)(6-y)(SiO4)(y)(OH)(2) (x = 0.2, 0.6, and 1.0 and y = 0.5) was successfully synthesised by using microwave-assisted wet precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometry (ICP-MS) techniques were used to characterise the synthesised nanoparticles. The results revealed that the incorporation of SiO44- ions increased the lattice parameters and decreased the crystallite size of HA. However, the incorporation of Co(2+)ions led to the reduction of lattice parameters and the particle size of the SiHA nanoparticles. In vitro antibacterial activity of materials was evaluated using disk diffusion and minimum inhibitory concentration (MIC) protocols. The findings indicated that incorporating Co2+ ions into SiHA inhibited the growth of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The cytotoxicity of materials evaluated using the Sarcoma osteogenic (Saos-2) cell line revealed that they were cytocompatible and exhibited no adverse side effects. The osteogenic differentiation of cells was confirmed by the significant increase in the alkaline phosphatase (ALP) activity by incorporating Co2+/SiO44- ions into the HA crystal structure. Our results show that the nanoparticles prepared in this study have a promising future in biomaterial-tissue engineering applications.
Biomechanical Evaluation of an Injectable Alginate / Dicalcium Phosphate Cement Composites for Bone Tissue Engineering
(Elsevier, 2021) Alshemary, Ammar Z.; Bilgin, Saliha; Isik, Gulhan; Motameni, Ali; Tezcaner, Aysen; Evis, Zafer
Biocompatible dicalcium phosphate (DCP) cements are widely used as bone repair materials. In this study, we aimed to investigate the impact of different amounts of sodium alginate (SA) on the microstructural, mechanical, and biological properties of DCP cements. Beta-tricalcium phosphate (?-TCP) was prepared using a microwaveassisted wet precipitation system. Lattice parameters of the obtained particles determined from X-ray diffraction (XRD), were in good match with a standard phase of ?-TCP. Scanning electron microscopy (SEM) examination revealed that the particles were in globular shape. Furthermore, all functional groups of ?-TCP were also detected using Fourier-transform infrared spectroscopy (FTIR) spectra. DCP cement (pure phase) was synthesized using monocalcium phosphate monohydrate (MCPM)/?-TCP powder mixture blended with 1.0 mL of water. SA/DCP cement composites were synthesized by dissolving different amounts of SA into water (1.0 mL) to obtain different final concentrations (0.5%, 1%, 2% and 3%). The prepared cements were characterized with XRD, SEM, FTIR and Thermogravimetric analysis (TGA). XRD results showed that pure DCP and SA/DCP cements were in a good match with Monetite phase. SEM results confirmed that addition of SA inhibited the growth of DCP particles. Setting time and injectability behaviour were significantly improved upon increasing the SA amount into DCP cements. In vitro biodegradation was evaluated using Simulated body fluid (SBF) over 21 days at 37 ?C. The highest cumulative weight loss (%) in SBF was observed for 2.0% SA/DCP (about 26.52%) after 21 days of incubation. Amount of Ca2+ ions released in SBF increased with the addition of SA. DCP and SA/DCP cements showed the highest mechanical strength after 3 days of incubation in SBF and declined with prolonged immersion periods. In vitro cell culture experiments were conducted using Dental pulp stem cells (DPSCs). Viability and morphology of cells incubated in extract media of DCP and SA/DCP discs after 24 h incubation was studied with MTT assay and fluorescence microscopy imaging, respectively. All cements were cytocompatible and viability of cells incubated in extracts of cements was higher than observed in the control group. Based on the outcomes, SA/DCP bone cements have a promising future to be utilized as bone filler.
Cellulose acetate-gelatin-coated boron-bioactive glass biocomposite scaffolds for bone tissue engineering
(Iop Publishing Ltd, 2020) Rad, Reza Moonesi; Alshemary, Ammar Z.; Evis, Zafer; Keskin, Dilek; Tezcaner, Aysen
In this study, we aimed to prepare and characterize porous scaffolds composed of pure and boron oxide (B2O3)-doped bioactive glass (BG) that were infiltrated by cellulose acetate-gelatin (CA-GE) polymer solution for bone tissue engineering applications. Composite scaffolds were cross-linked with glutaraldehyde after polymer coating to protect the structural integrity of the polymeric-coated scaffolds. The impact of B(2)O(3)incorporation into BG-polymer porous scaffolds on the cross-sectional morphology, porosity, mechanical properties, degradation and bioactivity of the scaffolds was investigated. Human dental pulp stem cells (hDPSCs) were enzymatically isolated and used for cell culture studies. According to scanning electron microscope analysis, the porous structure of the scaffolds was preserved after polymer coating. After polymer infiltration, the porosity of the scaffolds decreased from 64.2% to 59.35% for pure BG scaffolds and from 67.3% to 58.9% for B2O3-doped scaffolds. Meanwhile, their compressive strengths increased from 0.13 to 0.57 MPa and from 0.20 to 0.82 MPa, respectively. After polymer infiltration, 7% B2O3-incorporated BG scaffolds had higher weight loss and Ca-P layer deposition than pure BG scaffolds, after 14 d of incubation in simulated body fluid at 37 degrees C. Higher attachment and proliferation of hDPSCs were observed on 7% B2O3-BG-CA/GE scaffolds. In addition, the alkaline phosphatase activity of the cells was about 1.25-fold higher in this group than that observed on BG-CA/GE scaffolds after 14 d of incubation in osteogenic medium, while their intracellular calcium amounts were 1.7-fold higher than observed on BG-CA/GE after 7 d of incubation in osteogenic medium. Our results suggested that porous cellulose acetate-gelatin-coated boron-BG scaffolds hold promise for bone tissue engineering applications.
Co-doped hydroxyapatites as potential materials for biomedical applications
(Elsevier Science Bv, 2019) Yilmaz, Bengi; Alshemary, Ammar Z.; Evis, Zafer
Hydroxyapatite (HA) is a synthetic biomaterial resembling the composition of mammalian hard tissue and thus, it is widely employed as a bone graft material, hard tissue engineering scaffold and coating layer for metallic substrates. Biological apatite is non-stoichiometric in nature. It is composed of small crystals and characterized by poor crystallinity and relatively high solubility with respect to stoichiometric HA. Chemical compositions of these crystals consist of Ca, P and trace amounts of various ions, such as Mg2+, Zn2+, Sr2+, Ag+, Cl- and F- which are more prominent as dopants or adsorbed on the crystal surface. However, these ions play an important role in the metabolism of hard tissues. Synthetic HA is a stoichiometric material with a Ca/P ratio of 1.67, which lacks the presence of valuable trace ions regularly present in natural hard tissue. Thus, the structure of synthetic HA is partially incorporated by these ions to mimic the chemical composition of the biological apatite structure. Ionic substitutions have been planned as a tool to enhance the biological role of HA based materials. As single dopant frameworks have indicated great outcomes, it makes sense that various dopants can be utilized to further build the valuable impacts of each, within the constraints of the material stability of HA. This review is focused on co-ionic substitutions in HA system and their combined effects on related biomedical characteristics.
Effects of the doping concentration of boron on physicochemical, mechanical, and biological properties of hydroxyapatite
(Elsevier Sci Ltd, 2022) Jodati, Hossein; Tezcaner, Aysen; Alshemary, Ammar Z.; Sahin, Volkan; Evis, Zafer
Ion doping is an approach to modify properties of materials, like hydroxyapatite (HA), that contributes to designing biomaterials with desired characteristics applicable in bone defect treatments. Recently, boron (B) has been noticed in biomaterial fields due to its beneficial effects on formation, growth, and quality of bone. In this study, B-doped HA nanoparticles with different molar concentrations of B (0.05, 0.1, 0.25, and 0.5) were synthesized through microwave-assisted wet precipitation. The effects of B content on various properties of HA were evaluated. The results demonstrated that the size of HA particles reduced from 106 nm to 89-85 nm in B doped materials. Meanwhile, the crystallinity degree of B doped HA (BHA) samples was between 89.90% and 93.77%, compared to 95.19% of HA. Diametral tensile strength of samples was measured in the ranges of 2.51 and 3.61 with no significant difference among groups. The micro-hardness of HA was 0.88 GPa, whilst doped ones had hardness values of 0.5 GPa-0.68 GPa. Biodegradability of samples increased from less than 1% to approximately 4% after 28 days, while B-doping did not make any change in the degradation rate. Doping dosages were appropriate in terms of bioactivity and cell viability, and B doping caused higher bioactivity and cell proliferation. All changed properties were dose-dependent and more effective in doped groups with a higher amount of B. Despite proliferative effect, <= 260 mu g/l and 770 mu g/l of B release in two groups with the highest dopant concentrations did not positively influence the osteogenic activity of cells. Our results demonstrated that doping concentrations that resulted in B release & LE;260 mu g/l seem more appropriate dosage, especially for bone tissue engineering and substitute applications due to promoted bioactivity and proliferation, as well as no obstructive effects on mechanical properties and osteogenic activities of HA.
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.
Impact of B2O3 and La2O3 addition on structural, mechanical and biological properties of hydroxyapatite
(Univ Novi Sad, Fac Technology, 2018) Khoshsima, Sina; Alshemary, Ammar Z.; Tezcaner, Aysen; Surdem, Sedat; Evis, Zafer
In this study, hydroxyapatite-B2O3-La2O3 composites (with <= 20 wt.% B2O3 and <= 2 wt.% La2O3) were synthesized via wet precipitation method and calcined at 1100 degrees C for 1 h. X-ray diffraction (XRD) analysis revealed the existence of the pure hydroxyapatite (HA) phase with high crystallinity. Characteristic absorption bands of HA were also observed in Fourier transform infrared spectra. Furthermore, scanning electron microscopy images demonstrated that the addition of B2O3 and La2O3 into HA enhanced the particle growth. Mechanical properties of the composites were studied by diametral tensile test and the results showed that incorporation of 10 wt.% B2O3 and 2 wt.% La2O3 led to a 39% increase in tensile strength (compared to the pure HA). In vitro cytocompatibility of HA-B2O3-La2O3 composites was investigated using Osteosarcoma Cell Lines (Saos-2). Incorporation of B2O3 and La2O3 into HA had no toxic effect towards the cells. Based on its tensile strength properties and biological response, composite of 88 wt.% HA, 10 wt.% B2O3 and 2 wt.% La2O3 was suggested as a promising composite for bone tissue engineering applications.
Lanthanum doped dicalcium phosphate bone cements for potential use as filler for bone defects
(Elsevier, 2021) Motameni, Ali; Alshemary, Ammar Z.; Dalgic, Ali Deniz; Keskin, Dilek; Evis, Zafer
The bone defects arising as a result of trauma should be filled to provide a framework to support and encourage the growth of new and living bone tissues. Among the many synthetic bone graft substitutes, self-hardening calcium phosphate (CP) cements have been widely used to repair hard tissue defects. In this study, pure dical-cium phosphate (DCP) and lanthanum (La) modified dicalcium phosphate (La-DCP) bone cements were prepared based on acid/base reaction between beta-tricalcium phosphate (beta TCP) (or La-beta TCP) and monocalcium phosphate monohydrate (MCPM) in the presence of water. The prepared bone cements were characterized using XRD, FTIR and SEM techniques to verify both La doping and to explore the alterations in the structural and molecular properties upon doping. With minimum addition of La3+ ions (0.090 mol), the pure phase of brushite trans-formed into monetite and the plate-like crystals of brushite turned into spheroid particles. The setting times of DCP bone cement declined gradually upon boosting amount of La3+ ions in DCP lattice. As the La amount in DCP cements rose from 0 to 0.225 mol, the compressive strength also increased from 7.90 +/- 0.8 to 9.64 +/- 1.47 MPa. The dissolution rate of DCP cements improved with addition of La3+ ions. Adsorption/desorption of Fetal bovine serum (FBS) on/from the prepared DCP bone cements showed higher protein loading of La-DCP cements than pure DCP. In vitro experiments on proliferation, adhesion, and osteogenic differentiation of Sarcoma osteogenic (Saos-2) cells indicated that addition 0.225 mol of La3+ ions promoted these properties compared to pure DCP. Results suggested that La3+ (0.225 mol) incorporated DCP bone cement (2La-DCP) has a potential to be used as a bone filler material.
Nanocrystalline Zn2+ and SO42- binary doped fluorohydroxyapatite: A novel biomaterial with enhanced osteoconductive and osteoinconductive properties
(Elsevier, 2019) Alshemary, Ammar Z.; Pazarceviren, Engin Ahmet; Dalgic, Ali Deniz; Tezcaner, Amen; Keskin, Dilek; Evis, Zafer
In this study, we have successfully doped hydroxyapatite (HA) with zinc (Zn2+), sulphate (SO42-) and fluoride (F-) ions to develop a new composition of bioceramic, Ca10-xZnx(PO4)(6-y)(SO4)(y)(OH)(2-z-y)F-z(SO4)(y), (x = 0, 0.2, 0.6, 1.0, y = 0, 0.5 and z = 0,1.0 mol), using wet precipitation method. The obtained materials were analysed using XRD, FTIR, FESEM, and XPS techniques to investigate the phase purity, particle morphology and elemental composition, respectively. A model anticancer drug (Doxorubicin, DOX) was loaded onto the surface of the Zn/SO4-FHA materials. About 100% loading of DOX with a controlled release profile was obtained. Degradation of materials in Simulated body fluid (SBF) was greatly improved with the incorporation of Zn2+/SO42- ions in comparison to HA/FHA, which makes it highly bioactive materials. In vitro cell viability and adhesion of Human fetal osteoblast (hFOB) cell were investigated. Cell viability has demonstrated that the hFOB cells proliferated at a high rate on Zn/SO4-FHA materials, confirming the in vitro biocompatibility of the materials. Alkaline phosphatase (ALP) activity and intracellular calcium deposition of hFOB cells seeded on 1ZnSO(4)-FHA disc surface was statistically higher than observed on pure HA and FHA discs, indicating that hFOB cells differentiated into mature osteoblasts on 1Zn/SO4-FHA disc surfaces. Taken together, our results suggest that HA substituted by (Zn2+, 0.2 mol), (SO42-, 0.5 mol) and (F-, 1 mol) (1Zn/So(4)-FHA) material was a promising material for hard tissue scaffolds.
Physico-chemical and biological properties of hydroxyapatite extracted from chicken beaks
(Elsevier Science Bv, 2018) Alshemary, Ammar Z.; Akram, Muhammad; Taha, Ali; Tezcaner, Aysen; Evis, Zafer; Hussain, Rafaqat
In this investigation, we have extracted biological hydroxyapatite (HA) containing magnesium, sodium, aluminium, zirconium and silicon ions from the chicken beaks. Raw chicken beaks were calcined at different temperatures after washing with boiled water and organic solvents. The calcined biological HA was characterized by X-ray diffraction (XRD), Fourier transforms infrared (FTIR), Field emission electron microscopy (FESEM), X-ray fluorescence (XRF) spectroscopy and Thermogravimetric analysis (TGA). The viability of Saos-2 cells treated with extracts of biological HA was higher than cells on tissue culture plates (TCPs) and synthetic HA, suggesting a good cytocompatibility of biological HA. Our research has successfully shown that the chicken beaks are a cheap source of biological HA. (C) 2017 Elsevier B.V. All rights reserved.
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.
A review of synthesis methods, properties and use of monetite cements as filler for bone defects
(Elsevier Sci Ltd, 2021) Motameni, Ali; Alshemary, Ammar Z.; Evis, Zafer
The major objective of the current review is to highlight the prime importance of bone cements particularly monetite cement as filler to treat various bone defects which may result due to osteoporosis, some accidents, some trauma disease or any other orthopedic surgical disorders. Previous studies showed that polymethyl methacrylate (PMMA), calcium phosphate cements (CPCs), dicalcium phosphate (DCP) cement and acrylic polymer cements have been employed to improve the bone defects, but these materials have a certain issue of insitu setting. To overcome these problems, concentration was swiftly diverted towards monetite cement which revealed better results. Therefore, in this review, more focus has been given to the monetite cement. In this work, a brief but very productive discussion has also been inducted about the various synthetic routes to synthesize monetite cement and its properties which will help the readers to get key information about the growing significance of monetite cement as a bone filler and its future use and importance. The main theme of this review is to highlight the tremendous achievements achieved in the monetite cementing materials and their further scope in the near future as to upgrade their properties and use in the biomedical field.
Silicate-doped nano-hydroxyapatite/graphene oxide composite reinforced fibrous scaffolds for bone tissue engineering
(Sage Publications Ltd, 2018) Dalgic, Ali Deniz; Alshemary, Ammar Z.; Tezcaner, Aysen; Keskin, Dilek; Evis, Zafer
In this study, novel graphene oxide-incorporated silicate-doped nano-hydroxyapatite composites were prepared and their potential use for bone tissue engineering was investigated by developing an electrospun poly(epsilon-caprolactone) scaffold. Nanocomposite groups were synthesized to have two different ratios of graphene oxide (2 and 4 wt%) to evaluate the effect of graphene oxide incorporation and groups with different silicate-doped nano-hydroxyapatite content was prepared to investigate optimum concentrations of both silicate-doped nano-hydroxyapatite and graphene oxide. Three-dimensional poly(epsilon-caprolactone) scaffolds were prepared by wet electrospinning and reinforced with silicate-doped nano-hydroxyapatite/graphene oxide nanocomposite groups to improve bone regeneration potency. Microstructural and chemical characteristics of the scaffolds were investigated by X-ray diffraction, Fourier transform infrared spectroscope and scanning electron microscopy techniques. Protein adsorption and desorption on material surfaces were studied using fetal bovine serum. Presence of graphene oxide in the scaffold, dramatically increased the protein adsorption with decreased desorption. In vitro biocompatibility studies were conducted using human osteosarcoma cell line (Saos-2). Electrospun scaffold group that was prepared with effective concentrations of silicate-doped nano-hydroxyapatite and graphene oxide particles (poly(epsilon-caprolactone) - 10% silicate-doped nano-hydroxyapatite - 4% graphene oxide) showed improved adhesion, spreading, proliferation and alkaline phosphatase activity compared to other scaffold groups.
Strontium and fluorine co-doped biphasic calcium phosphate: characterization and in vitro cytocompatibility analysis
(Iop Publishing Ltd, 2017) Pourreza, Elmira; Alshemary, Ammar Z.; Yilmaz, Bengi; Rad, Reza Moonesi; Tezcaner, Aysen; Evis, Zafer
Strontium (Sr2+) and fluoride (F-) ions are known to play an important role in bone and tooth metabolism. In this work, we prepare biphasic calcium phosphate (BCP) bioceramics co-doped with different fractions of Sr2+ and F- ions to investigate the impact of dopant on the crystal structure and biological properties of BCP bioceramics. The materials were successfully synthesized using a wet precipitation method, followed by sintering at 1100 degrees C for 1 h. The sintered materials were characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). XRD analysis revealed that the BCP bioceramics were composed of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), along with calcium oxide (CaO) as impurity. Furthermore, the percentage of beta-TCP tended to increase with an increase in the Sr2+ ion concentration. The lattice parameters of HA phase expanded along with incorporation of Sr2+ and F- ions. The morphology of the yielding materials demonstrated that the incorporation of Sr2+ and F- ions caused a decrease in the grain size. The Vickers hardness (HV) test showed that hardness values increased with increasing Sr2+ concentrations. In vitro cell culture tests were performed with human osteogenic sarcoma (Saos-2) cell line. Saos-2 cells attached and proliferated faster on Sr/F-BCP materials compared to pure BCP, showing that Sr/F-BCP materials were cytocompatible.
Structural and Biological Analysis of Mesoporous Lanthanum Doped ?TCP For Potential Use as Bone Graft Material
(Elsevier, 2020) Motameni, Ali; Dalgic, Ali Deniz; Alshemary, Ammar Z.; Keskin, Dilek; Evis, Zafer
In this study, mesoporous particles of beta-tricalcium phosphate (beta TCP, beta Ca-3(PO4)(2)) and lanthanum (La) doped beta TCP were synthesized using wet precipitation method attached with microwave refluxing system. The obtained materials were characterized and analysed using different sort of techniques such; X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Inductively coupled plasma optical emission spectroscopy (ICP-OES), Brunauer-Emmett-Teller (BET) and helium pycnometer. With incorporation of La3+ ions, relevant expansion in lattice parameters of beta TCP crystal was observed along with inhibition growth rate was observed. beta TCP and La-beta TCP materials were mesoporous in nature, pore diameter and pore volume were expanded with incorporation of La3+ ions. The loading/release on beta TCP and La-beta TCP particles surfaces were evaluated using fetal bovine serum (FBS) proteins. In vitro cell culture studies were performed with human osteosarcoma cell line (Saos-2). The outcomes approved that all La-beta TCP materials were cytocompatible and strict dose dependent effect of La3+ ions was observed on cell viability and alkaline phosphatase (ALP) activity. These results strongly suggest that La-beta TCP materials have a potential application in bone tissue engineering.
Structural and biological assessment of boron doped bioactive glass nanoparticles for dental tissue application (vol 44, pg 9854, 2018)
(Elsevier Sci Ltd, 2018) Rad, Reza Moonesi; Alshemary, Ammar Z.; Evis, Zafer; Keskin, Dilek; Altunbas, Korhan; Tezcaner, Aysen
[No abstract available]
Structural and biological assessment of boron doped bioactive glass nanoparticles for dental tissue applications
(Elsevier Sci Ltd, 2018) Rad, Rezai Moonesi; Alshemary, Ammar Z.; Evis, Zafer; Keskin, Dilek; Altunbas, Korhan; Tezcaner, Aysen
In this article, bioactive glass nanoparticles (BG-NPs) doped with boron were synthesized and characterized to evaluate their effects on human dental pulp stem cells (hDPSCs). All synthesized BGs were nano-sized and amorphous in nature. They showed the expected characteristic functional groups and composition close to the designed ones by microstructural characterizations. Porositimetry analysis revealed that increase of boron in the BG composition caused a decrease in the specific surface area, average pore diameter and total pore volume of NPs. hDPSCs were isolated from third molar teeth of patients and were shown to have the characteristics of mesenchymal stem cells. Dose dependent cytotoxicity study of boron doped BG-NPs suggested that 6.25 mg/ml was the optimum concentration for cells. ALP activity tests and intracellular calcium measurements revealed enhanced early stage odontogenic differentiation of hDPSCs treated with 6.25 mg/ml of different BG groups. Immunocytochemical staining showed positive effect of boron doped BG-NPs on DSPP, osteopontin and collagen I markers expression of hDPSCs. Our results indicated that boron doped BG-NPs hold potential as biomaterial in regenerative dentistry.
Synthesis and sintering of B, Sr, Mg multi-doped hydroxyapatites: Structural, mechanical and biological characterization
(Elsevier, 2021) Yedekci, Busra; Tezcaner, Aysen; Alshemary, Ammar Z.; Yilmaz, Bengi; Demir, Teyfik; Evis, Zafer
Hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)) is the main constituent mineral of bone and teeth in mammals. Due to its outstanding biocompatibility and osteoconductive capabilities, it is preferred for bone repair and replacement. Owing to high potential to have excellent biological properties, ternary ions-doped HAs have just begun to be investigated in the biomedical field and preparing multi-doped HAs is a fairly new approach. Boron (B, BO33-), strontium (Sr, Sr2+) and magnesium (Mg, Mg2+) provide a beneficial effect on bone growth, bone strength, biocompatibility and positively affect bone microstructure. The motivation of this study is taking advantages of the potential of the combine effects of these bivalent ions. In this study, 8 different compositions of BO33- , Sr2+, Mg2+ multi-doped HAs were synthesized by microwave irradiation method to investigate the structural, mechanical and biological features of bone substitutes. This is the first time we report the effect of boron, strontium and magnesium ions multi-doping on the structure of HA and its biological properties. Samples were sintered at 700, 900 and 1100 degrees C. The effect of varying ion contents and sintering temperature on structural and biological properties of the multi-doped samples was investigated. B, Sr and Mg ions were successfully doped into the HA structure according to X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. A biphasic structure was obtained with increasing amount of ion-doping. Increasing the sintering temperature affected the crystallinity and the density of the samples gradually. Vicker's microhardness and diametral strength of the samples increased at high sintering temperatures. B-Sr-Mg multi-doped HA promoted osteoblast-like Saos-2 cell proliferation, and as the sintering temperatures of the samples increased, the osteogenic differentiation level of the cultured cells also increased. Overall, results showed that the biological properties of HA were improved with the doping of Sr, Mg and B ions, and for bone implant applications samples sintered at 1100 degrees C were suggested to have potential as a biomaterial.

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