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1

Mechanical and Microstructural Properties of Sheep Hydroxyapatite (SHA)-Niobium Oxide Composites

100%

Demirkol N., Oktar F., Kayali E.

Acta Physica Polonica A

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2012

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vol. 121

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issue 1

274-276

EN

The aim of this study is to produce and to investigate the mechanical and microstructural properties of composite materials made of hydroxyapatite, obtained from natural sheep bone and niobium oxide (5 and 10 wt%). Sheep hydroxyapatite (SHA) matrix was reinforced with 5 and 10 wt% of niobium (Nb) oxide powder. The calcinated SHA was ball milled separately with 5% and 10% niobium oxide for 4 h. The samples were subjected to sintering at different temperatures between 1000C and 1300°C. The mechanical properties were determined by measuring compression strength and Vickers microhardness (HV). X-ray diffraction and scanning electron microscopy studies were carried out to analyze the microstructure. With increasing sintering temperature, mechanical properties of composites increased. The SHA-composites with 10 wt% niobium oxide addition had better mechanical properties at all sintering temperatures. The highest mechanical properties were obtained in SHA-10 wt% niobium oxide composite sintered at 1300°C. Adding of niobium oxide to SHA could be a valuable method to produce rigid and high load carrying ability HA composite which is suitable for orthopedic applications.

2

Hydroxyapatite Synthesis from Fish Bones: Atlantic Salmon (Salmon Salar)

64%

Komur B., Altun E., Aydogdu M., Bilgiç D., Gokce H., Ekren N., Salman S., Inan A., Oktar F., Gunduz O.

Acta Physica Polonica A

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2017

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vol. 131

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issue 3

400-402

EN

Production of the bioceramics on the market is presently conducted from typical precipitation method by using reagent grade raw chemicals or through calcination of natural sources like animal bones (especially bovine bone) and fish bones. Usually fish bones were damped near or in the water sources, which can lead to serious environmental pollution. Those were regarded as a trash, even though they still bear economic value, including conjugates. In this study bones of Atlantic Salmon (Salmo salar) were used as a bioceramic material source. Bones of Atlantic Salmon were collected from Besiktas Fish Market. Those were cleaned from possible flesh with reagent grade NaOH. Cleaned parts were washed with demineralized water very neatly. Dry fish bones were calcinated at 850°C for 4 hours. The obtained hydroxyapatite material was characterized with scanning electron microscopy and X-ray diffraction methods. It was found that the bioceramic material consisted of hydroxyapatite and various related phases. Scanning electron microscopy studies have revealed nano-structured bioceramic particles. The aim of this study is to obtain nano-structured bioceramics from bones of Atlantic Salmon in an environmentally friendly and economic way.

3

Bioceramic Production from Sea Urchins

64%

Ağaoğullari D., Kel D., Gökçe H., Duman I., Öveçoğlu M., Akarsubaşi A., Bılgıç D., Oktar F.

Acta Physica Polonica A

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2012

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vol. 121

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issue 1

23-25

EN

Bioceramic nanopowders, currently one of the most demanding challenges for producing new biomaterials, have been tackled only when starting from chemical reagents. There are few studies aiming at producing hydroxyapatite nanopowders from naturally derived raw materials, such as nacre shells. Natural species of sea origin, such as corals and nacres, always attract special interest in biomaterials science and technology. Nacre shells are made up of pure aragonite crystallized in an organic matrix. The most common way to transform aragonite structures to hydroxyapatite is via hydrothermal transformation under very high pressure. However, such ways can be very dangerous if the equipment is worn. Ultrasonic and hotplate methods are apparently very safe. This work proposes a new approach for developing highly bioactive fine powders of Ca-phosphates (which can be used afterwards to build up hydroxyapatite-based bioceramic bone-scaffolds) from sea urchins via the above mentioned methods. The suspended raw powders were put on a hotplate (i.e. ultrasound). The temperature was set to 80C for 15 min and then, equivalent (to the amount of CaCO_3 in the sea urchins) amount of H_3PO_4 was added drop by drop into the solution. The reaction continued for 2 h. Then, to evaporate the liquid part, the mixture was put into an incubator at 100C for 24 h and the resultant dried sediment was collected. X-ray diffraction analysis identified various calcium phosphate phases, predominantly monetite, and tricalcium phosphate as a secondary phase. The worldwide availability and the low cost of all kinds of nacre and sea urchin shells, along with their biological-natural origin are attractive features conferring to them a high potential for preparing calcium phosphate materials for uses in biomedicine. Heart urchin, used in this study, can be an ideal candidate for producing bioceramic particles.

4

Nano-Bioceramic Synthesis from Tropical Sea Snail Shells (Tiger Cowrie - Cypraea Tigris) with Simple Chemical Treatment

64%

Şahin Y., Gündüz O., Bulut B., Özyeğin L., Gökçe H., Ağaoğulları D., Chou J., Kayalı E., Ben-Nissan B., Oktar F.

Acta Physica Polonica A

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2015

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vol. 127

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issue 4

1055-1058

EN

In this study several bioceramic materials (i.e. hydroxyapatite, whitlockite) were prepared by using chemical synthesis method from sea snail shells (Tiger Cowrie - Cypraea Tigris), originated from Pacific Ocean. Marine shells usually present aragonite-calcite structures and generally, complicated and pressurized equipment is necessary to convert these structures into bioceramics. Instead of using complicated systems, a basic ultrasonic equipment and simple chemical synthesis method was used in the process. DTA analysis was performed to calculate the required amount of H₃PO₄ solution in order to set the appropriate stoichiometric ratio of Ca/P equal to 1.667 for HA bioceramic or to 1.5 for β-TCP bioceramic in the titration. The prepared batches were sintered at 800°C and 400°C for hydroxyapatite (HA) and β-tri calcium phosphate (β-TCP) forms respectively. X-ray diffraction analysis, scanning electron microscopy (SEM) and infrared observations (FTIR) were implemented for both TCP and HA bioceramics. By applying the chemical synthesis with basic ultrasonic equipment, this study proposes a simple way of production for nano-HA /TCP powders from a natural marine sources.

5

Characterization of Cu/Ag/Eu/Hydroxyapatite Composites Produced by Wet Chemical Precipitation

64%

Komur B., Ozturk E., Ekren N., Inan A., Gunduz O., Andronescu E., Ficai A., Oktar F.

Acta Physica Polonica A

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2017

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vol. 131

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issue 3

392-396

EN

In the first part of this study hydroxyapatite was prepared synthetically through classical wet precipitation, using Ca(NO₃)₂·4H₂O (calcium nitrate tetrahydrate) as calcium source and HgN₂O4P as phosphate source. In the second part of the study HA compounds were prepared with different ratios (0.5, 1, 2, 5, 10 and 25 wt.%) of antibacterial materials like copper (Cu), silver (Ag) and europium (Eu), using the same wet precipitation method. The prepared pure HA material was utilized as the control group for comparison with Cu/Ag/Eu/HA composites. Studies of X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, equipped with energy dispersive X-ray analysis were performed. The aim of this study was to investigate Cu/Ag/Eu/HA composites and the effect of metals on HA biomaterials, used as scaffold materials in bone disease treatment.

6

Physical Characterization of Turbot (Psetta Maxima) Originated Natural Hydroxyapatite

64%

Inan A., Komur B., Ekren N., Aydogdu M., Gokce H., Ficai A., Salman S., Oktar F., Gunduz O.

Acta Physica Polonica A

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2017

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vol. 131

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issue 3

397-399

EN

Nowadays hydroxyapatite is one of the most popular biomaterials, which is used in various medical and dental applications areas as graft material. Bovine bone is the biggest source for natural hydroxyapatite production, but its production can lead to very dangerous disease, like mad cow disease, without high degree calcination. Hydroxyapatite produced from marine sources is much safer and easier to produce than bovine hydroxyapatite. Here in this study natural hydroxyapatite and related phases were produced from a local source turbot (Psetta maxima). Beside the main bony internal structure, there are koshers (cycloid scale) on its skin. Koshers are bulky bumps, looking like flat, small and rounded structures. Internal bones and those bulky bumps were cleaned from flesh with chemicals and calcined at 850°C for 4 hours. After calcinations, especially those bulky bumps, were formed into mesoporous structures with very light bluish color. Those mesoporous structures can be used as natural mesoporous hydroxyapatite structures for bone grafting purposes. The internal bones have also formed hydroxyapatite. Scanning electron microscope and X-ray diffraction studies were performed. I this study it is found that the bones of turbot consist of hydroxyapatite and TCP related phases. The aim of this study is to produce natural hydroxyapatite structures from turbot scale with low carbon footprint, without harming the environment and without using complex chemicals.

Refine search results

Mechanical and Microstructural Properties of Sheep Hydroxyapatite (SHA)-Niobium Oxide Composites

Hydroxyapatite Synthesis from Fish Bones: Atlantic Salmon (Salmon Salar)

Bioceramic Production from Sea Urchins

Nano-Bioceramic Synthesis from Tropical Sea Snail Shells (Tiger Cowrie - Cypraea Tigris) with Simple Chemical Treatment

Characterization of Cu/Ag/Eu/Hydroxyapatite Composites Produced by Wet Chemical Precipitation

Physical Characterization of Turbot (Psetta Maxima) Originated Natural Hydroxyapatite