A new method for fabrication of nanohydroxyapatite and TCP from the sea snail Cerithium vulgatum

Biphasic bioceramic nanopowders of hydroxyapatite (HA) and β-tricalcium phosphate (TCP) were prepared from shells of the sea snail Cerithium vulgatum (Bruguière, 1792) using a novel chemical method. Calcination of the powders produced was carried out at varying temperatures, specifically at 400°C and 800°C, in air for 4 hours. When compared to the conventional hydrothermal transformation method, this chemical method is very simple, economic, due to the fact that it needs inexpensive and safe equipment, because the transformation of the aragonite and calcite of the shells into the calcium phosphate phases takes place at 80°C under the atmospheric pressure. The powders produced were determined using infrared spectroscopy (FT-IR), X-ray diffraction, and scanning electron microscopy (SEM). The features of the powders produced along with the fact of their biological origin qualify these powders for further consideration and experimentation to fabricate nanoceramic biomaterials. © 2014 O. Gunduz et al

Wettability characteristics of an Al2O3/SiO2-based ceramic modified with CO2, Nd:YAG, excimer and high-power diode lasers

Interaction of CO2, Nd:YAG, excimer and high power diode laser (HPDL) radiation with the surface of an Al2O3/SiO2 based ceramic was found to effect significant changes in the wettability characteristics of the material. It was observed that interaction with CO2, Nd:YAG and HPDL radiation reduced the enamel contact angle from 1180 to 310, 340 and 330 respectively. In contrast, interaction with excimer laser radiation resulted an increase in the contact angle to 1210. Such changes were identified as being due to: (i) the melting and partial vitrification of the Al2O3/SiO2 based ceramic surface as a result of interaction with CO2, Nd:YAG HPDL radiation. (ii) the surface roughness of the Al2O3/SiO2 based ceramic increasing after interaction with excimer laser radiation. (iii) the surface oxygen content of the Al2O3/SiO2 based ceramic increasing after interaction with CO2, Nd:YAG and HPDL radiation. The work has shown that the wettability characteristics of the Al2O3/SiO2 based ceramic could be controlled and/or modified with laser surface treatment. In particular, whether the laser radiation had the propensity to cause surface melting. However, a wavelength dependance of the change of the wetting properties could not be deduced from the findings of this work

Calcium phosphate formation from sea urchin - (brissus latecarinatus) via modified mechano-chemical (ultrasonic) conversion method

This study aims to produce apatite structures, such as hydroxyapatite (HA) and fluorapatite (FA), from precursor calcium phosphates of biological origin, namely from sea urchin, with mechano-chemical stirring and hot-plating conversion method. The produced materials were heat treated at 800 °C for 4 hours. X-ray diffraction and scanning electron microscopy (SEM) studies were conducted. Calcium phosphate phases were developed. The SEM images showed the formation of micro to nano-powders. The experimental results suggest that sea urchin, Brissus latecarinatus skeleton could be an alternative source for the production of various mono or biphasic calcium phosphates with simple and economic mechano-chemical (ultrasonic) conversion method

Influence of synthesis process on the dielectric properties of B-doped SiC powders

Fine powders (similar to 0.7 mu m) of SiC doped with 3 mol% and 10 mol% B were successfully produced by mechanical activation assisted self-propagating high-temperature synthesis (MASHS). The experimental results showed that the presence of B caused a reduction in the combustion temperature, shrinkage of the crystal lattice, an increase in the tendency of the grains to be crystallized, and a decrease in the dielectric properties in the frequency range between 8.2 and 12.4 GHz, specifically the real (epsilon') and the imaginary parts (epsilon '') of complex permittivity and the loss tangent (tan delta). Analysis of the results suggests that B ions should be preferably accommodated in the Si sites of the SiC lattice and cause a reduction in the number of defects (V-si, V-c, and C-si), which results in a decrease in the dielectric properties. Comparison of the experimental results of this study with results reported in similar earlier studies reveals that the influence of B on the dielectric properties of the B-SiC powders depends strongly on the synthesis process. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Ceramics Internationa

A Review of Recent Investigations on Zirconia Joining for Biomedical Applications

Since non-reactive zirconia/metal systems result in low adhesion joints, reactive systems which involve Ti, either as a component of brazing fillers or as a bulk material in the form of Ti or TiAlV, are addressed. The case of direct bonding of zirconia with Ti as well as the influence of Ag-Cu, Pt, Au, Ag and Zr as brazing agents in the joining process and the stability of the resulting joint are discussed in detail. The microstructure of the interfaces is presented with regard to biomedical applications and the anticipated mechanical performance of the joints.Ceramic Transaction

Hydroxyapatite scaffolds produced from cuttlefish bone via hydrothermal transformation for application in tissue engineering and drug delivery systems

An increase in life expectancy due to improvements in healthcare, in parallel with high percentage of injures, because of traffic accidents and sport activities, has emerged as the primary reasons for the replacements of lost, infected, and damaged bones. Combined with tissue engineering, this is an area of great interest to regenerative medicine. Novel scaffolds development, providing a suitable environment that can favor osteoinduction for the newly formed bone is needed. Composite porous hydrogels, based on alginate and chitosan with the dispersed phase from powders of bioceramics, such as hydroxyapatite (HAp), are recently developed for this reason. This work presents a reverse and novel approach, where these two popular hydrogels are infiltrated in a 3D HAp-scaffold. More specifically, HAp is obtained from aragonite from cuttlefish bone via hydrothermal transformation. This reinforcement of HAp with alginate or chitosan hydrogels, through infiltration method gives to the final product proper mechanical potential for hard tissue regeneration. The structure of the produced scaffolds resembles the microstructure and the texture of the natural bone. These advanced scaffolds are easily handled by the surgeon while maintaining their porous structure during the implantation process to promote the regeneration of newly formed bone tissue. In particular, once such a scaffold is implanted in an area where the bone tissue is lost, biological liquids will be able to penetrate into the pores of the lyophilized composite scaffold. The polymeric matrix will then be dissolved and the remaining HAp, or its precursor compounds, which will eventually transform into HAp, will promote osteoinduction. The worldwide availability and the low cost of cuttlefish bone, along with their biological-natural origin are attractive features making them highly sorted material used in the preparation of advanced scaffolds containing HAp for applications in biomedicine. The optimization of the fabrication technique is required to unravel the endless potential of biomaterials, shedding light on this promising interdisciplinary field, which includes both tissue engineering and drug delivery system approaches. © Springer Nature Singapore Pte Ltd 2019

Wettability and interfacial interactions in bioceramic-body-liquid systems

Wetting experiments, by the sessile drop technique, were carried out at 37 degrees C in air to determine the surface and interfacial interactions that take place in various solid bioceramics based on Al2O3, ZrO2(YPZ), SiO2, and TiO2 in contact with water, Ringer solution, artificial synovial fluid, calf serum, human plasma, and whole blood (+ EDTA). The surface energy of the liquids was measured by the ring method. The calculated values of the energy of interaction (work of adhesion) reveal that intermolecular forces act across the solid-liquid interfaces. The contribution of the dispersion and polar interactions to the surface energy of the polar liquids and the pure or mixed oxides was determined assuming that in the system of Mn-steel-liquids only dispersion forces act at the interface. It was found that the contribution of the polar interactions to the energy of interaction at the solid-liquid interface increases with the glassy phase content of the oxide that causes reduction of the measured contact angle.J Biomed Mater Re