Key Engineering Materials Vol. 908

Abstract: The eggs are not only a good source of nutrients but their shells are rich in various minerals of which CaCO₃ is the most prominent. Egg shell contains about 90% CaCO₃ of the total weight. The interest in clean technology has attracted the use of eggshell waste as a focus of research. The objective of this work is to extract calcium oxide (CaO) from calcium carbonate (CaCO₃) available in chicken eggshells. CaO is white in colour possessing high porosity with narrow particle size distribution. CaO have very high percentage of ceramic yield. This CaO can be used as precursor for synthesis of calcium phosphate that can be further used in biomaterial synthesis. The uncalcined eggshell waste (ESW) and calcined ESW powders were characterized by using X-ray diffraction (XRD), Scanning electron microscope (SEM) and Fourier transform infra-red (FTIR) analyses. The calcination temperatures were varied from 700 ^oC to 1100 °C. XRD and FTIR results suggested that CaCO₃ is converted into calcium oxide at 900 °C and SEM micrographs also compliment these results. The calcination method can be used to extract calcium oxide from ESW being eco-friendly as well as low cost.

Abstract: The aim of this study is to investigate the effect of soaking time on the compositional and morphological changes of dicalcium phosphate dihydrate (DCPD)-coated β-tricalcium phosphate (β-TCP) bioceramic. In this study, an established method from our research group was used to prepare the β-TCP bioceramic pellets and expose them to acidic calcium phosphate solution for 2, 4, 6, and 8 hours to obtain DCPD coated layer on β-TCP pellets through dissolution-precipitation reaction. Characterization methods such as x-ray diffraction analysis (XRD) and scanning electron microscope (SEM) were carried out on the specimen. XRD and SEM analyses indicated that the peak intensity and density of DCPD crystal precipitated on the pellets were increased when increasing the soaking time. Therefore, it was confirmed that the DCPD coated layer formation on the β-TCP pellet surfaces depended on the exposure time to acidic calcium phosphate solution.

Abstract: This study concerns the evaluation of the bioactivity and cells response of strontium (Sr) doped sol-gel derived S53P4 bioglass due to Sr induced osteoblast. Moreover it prevents in-vitro osteoclastic activity and is clinically used as osteoporosis treatment. The different amount of Sr was doped into the S53P4 bioglass formulation (53.82%SiO₂-1.72%P₂O₅-22.64%Na₂O-(21.76-x)%CaO-x%SrO) (x=0, 3 and 5 mol %) and synthesized via sol-gel method. These samples were denoted as 0Sr, 3Sr and 5Sr respectively. After soaking in Hank's balanced salt solution (HBSS) for 7 and 14 days, the apatite formation was examined using X-ray powder diffraction (XRD) and scanning electron microscope (SEM) techniques. Proliferation and alkaline phosphatase activity were evaluated using osteoblastic cell line MC3T3-E1. The XRD and SEM findings confirmed the hydroxyapatite (HA) structure on the bioglass surface after soaking. More intense HA peaks were observed in 3Sr specimen on 7 day while in 5Sr specimen on 14 day. Meanwhile, 3Sr specimen showed the highest cells proliferation and ‌ significant difference in alkaline phosphatase (ALP) activity than 0Sr and 5Sr. As a result, this finding indicates that S53P4 bioglass with 3 mol % SrO (3Sr) is a good candidate for bone tissue engineering because it allows for optimum cell proliferation and ALP activity while also having a high bioactivity efficiency.

Abstract: The bioactivity properties of pure cordierite (C), pure β-wollastonite (W), and cordierite/β-wollastonite (CW) biocomposite ceramics were studied. Cordierite was prepared via melting, while β-wollastonite was prepared via the wet milling method. A bioactivity test showed that hydroxyapatite (HA) was non-existent in the pure cordierite sample after seven days of being soaked in simulated body fluid (SBF). On the other hand, the cordierite/β-wollastonite bioceramics showed that HA formation has entirely covered the surface of these samples. The XRD patterns showed that the crystallinity of W and CW samples has decreased due to the amorphous calcium phosphate (ACP) formation after seven days of soaking. SEM tests revealed that more ACP microstructures were present in cordierite/β-wollastonite samples than those in pure β-wollastonite. The effect of cordierite and β-wollastonite in biocomposite ceramics is described in this paper.

Abstract: Cordierite powders were synthesized via a melt-quench method. The samples were melted at 1550°C for 4 hours and immediately quenched in distilled water. The bioglass ceramic frit was milled and calcined to produce cordierite powders. After that, cordierite was treated with calcium acetate as a calcium salt in order to enhance the bioactivity of cordierite. The powders were immersed in calcium acetate solution for 24 hours and dried in the oven at 80°C for 24 hours. The mixtures were pressed into pellet form for bioactivity testing. Then, cordierite pellets were soaked in simulated body fluid (SBF) solution for 7 days. SEM micrographs show the formation of the hydroxyapatite layer on its surface after soaking in SBF solution. While EDX analysis shows the presence of calcium after the treatment. The presence of cordierite and hydroxyapatite phases were confirmed by XRD analysis.

Abstract: Hydroxyapatite is known as HAp, Ca₁₀(PO₄)₆(OH)₂, commonly used in orthopedics since it resembles the inorganic portion of human bone. Calcium, Ca and phosphorous, P are the main components of HAp, with Ca/P molar ratio of 1.67 capable of promoting bone growth. Large quantities of by-product waste from fisheries factories have a negative effect on the environment. Hence, this research was carried out to obtain biological natural HAp derived from fishery factory waste black tilapia fish bones. As a result, fish bone can be a low-cost source of HAp and important contributions in biomedical applications. To remove meat and other impurities, black tilapia fish bones were boiled at 100 °C followed by milling to produce a fine powder. The powder was calcined at 600 °C and 800 °C for 3 hours. Characterizations were done by using X-ray diffraction (XRD) for mineralogy, Scanning Electron Microscopy (SEM) for morphology and Energy Dispersive Spectroscopy, EDX for element analysis. The XRD results showed the existence of derived HAp, which was consistent with standard HAp. The raw samples tended to have denser and less porous microstructures than calcined samples were shown in SEM results. EDX results showed the chemical composition of Ca and P with present of magnesium, Mg and sodium, Na as their traces elements. The samples' Ca/P molar ratio was found to be higher than the stoichiometric HAp, >1.67. Thus, the findings show that producing calcium and phosphorus from fishery wastes is a viable option for biomedical applications with the present of trace elements to help accelerates bone growth.

Abstract: Extraction of the natural halal hydroxyapatite (HAp) from fish scale (Black Tilapia) was produced by calcining of raw fish scale at 600 °C and 800 °C. The produced powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an Energy Dispersive Spectroscopy, (EDX). The crystallite size, cell parameters, strain and crystallinity of the raw fish scale and derived HAp calcined powder were observed from the XRD results. By increasing the calcination temperature, the average crystallite size HAp amount increased and close to the pure HAp (JCPDS: 9-432). SEM analysis showed the raw fish scale surface morphology contains collagen fiber compared with boiled and after calcination of the powder samples. The calcined fish scale powders at 800°C morphology was discovered embraced of hexagonal fragments form. The EDX investigation exposed that the fish scale from HAp powder calcined at temperature 600 °C contain a high amount of magnesium and sodium compared to the powder that was calcined at 800 °C.

Abstract: Alginate microspheres are used for controlled drug delivery system; however, the formation and size control of alginate microspheres is necessary for these systems to be effective. Therefore, the influence of stirring speed on the characteristic of alginate microspheres (AMs) via emulsification/gelation method was evaluated. Alginate solution was emulsified into liquid paraffin oil to form water in oil emulsion and followed by cross-linked with Ca²⁺ ions. The shape and surface characteristics of AMs were determined by scanning electron microscope (SEM). Morphological observation shows that at lower stirring speed, the alginate particles were irregularly shaped with a rough surface. Whereas, increasing stirring speed resulted in spherical microspheres with smoother surface. Particle size analysis by laser diffraction method showed a decreased in mean particle size and more homogeneous distribution as the stirring speed increased. The mean particle size of AMs was found to be in the range of 28.5-69.6 μm. Fourier transform infrared (FTIR) analysis shows that there was no shifting in peak positions in the transmittance spectrum of AMs. This study suggested that the formation of AMs can be synthesis via emulsification/gelation method and the size of the AMs can be tailor by varying the stirring speed.

Abstract: This research study focused on the fabrication and characterization of sodium alginate incorporated with iron (III) oxide in the form of beads and biofilm for biomedical application. The fabrication of the samples was carried out by using solution casting method and syringe pump extrusion technique. Beads and biofilm of sodium alginate incorporated with iron oxide were characterized by several characterization testing such as XRD, FTIR and contact angle measurement. From the XRD testing shows the diffraction peak that confirmed the cubic structure of Maghemite. Then, FTIR analysis shows the presence of several intermolecular and intramolecular bond stretching of sodium alginate. Lastly, contact angle measurement exhibits that alginate incorporated with iron oxide has hydrophilic behavior due to the contact angle less than 90Also, it was found that as the contact angle reduced as the weight of iron oxide increased.

Abstract: The colossal dielectric permittivity of calcium copper titanate (CaCu₃Ti₄O₁₂, CCTO) provides a vast potential in miniaturizing electronic devices but become limited due to high dielectric loss. Hence, feldspar was introduced to reduce the dielectric loss and fill in the air gap of CCTO during the sintering process. The CCTO powder was prepared by the solid-state reaction method. The study focused on characterizing pure and feldspar added CCTO properties on phase formation and dielectric properties. The raw materials were weighed, followed by stoichiometric ratios for pure CCTO. While the addition of feldspar was added using a weight percentage ratio of 1%, 3%, 5%, 7% and 10%. The mixed powders were ball mixed for 24 hours using dry mixing. The mixed powder was calcined at 900°C for 12 hours and then pressed into a pellet with 6 mm diameter, then sintered at 1040°C for 10 hours. The X-ray Diffraction (XRD) machine and impedance analyzer were utilized to observe the phase formation and dielectric properties of the samples prepared. A single phase of CCTO was obtained after the sintering process except for pure CCTO and 1wt% of feldspar addition, and it still has remaining CuO in the ceramic. Even though feldspar can reduce the dielectric loss of the CCTO from 0.6 (pure CCTO) to 0.4 (10 wt%) at 1 MHz, it also hard to maintain the high dielectric constant. The dielectric constant of 1wt% of feldspar addition was recorded the highest value, up to 4000 at 1 MHz, while the lowest dielectric constant owned by 10wt% of feldspar addition, ~700 at 1 MHz.