Engineering Commons^™

When 1 + 1 > 2: Nanostructured Composites For Hard Tissue Engineering Applications, Vuk Uskoković

Pharmacy Faculty Articles and Research

Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. …

Effect Of Ion Concentration On Mechanosynthesis Of Carbonated Chlorapatite Nanopowders

Faculty of Engineering University of Malaya

Carbonated chlorapatite nanopowders (n-CCAp) with different degrees of substitution were successfully synthesized by the one-step mechanochemical process. Results demonstrated that the formation of n-CCAp was influenced strongly by the carbonate content (x). From X-ray analysis, crystallite size, crystallinity degree, and unit cell volume of n-CCAp decreased significantly as carbonate content (x) increased from 0 to 2. Conversely, the lattice strain and the volume fraction of grain boundaries grew considerably. Microscopic analysis showed the average particle size of the synthesized powders was 15 +/- 10 nm. The influence of carbonate concentration on mechanosynthesis of pure n-CCAp utilizing a facile solid-state process …

Effect Of High-Energy Ball Milling On The Formation And Micro Structural Features Of Carbonated Chlorapatite Nanopowders

Faculty of Engineering University of Malaya

Carbonated chlorapatite nanopowders (n-CCAp) were synthesized by mechanochemical process from calcite (CaCO3), phosphorus pentoxide (P2O5), and calcium chloride (CaCl2) as raw materials. Results demonstrated that the formation of n-CCAp was influenced strongly by the milling time. At the beginning of milling (up to 15 min), CaCO3 and CaCl2 were the dominant phases, while P2O5 disappeared entirely due to its very high deliquescent nature. With increasing the milling time to 600 min, the progressive mechanochemical reaction was completed which resulted in the formation of nanostructured carbonated chlorapatite. According to the X-ray diffraction data, crystallite size of the product decreased from 24 …

Microstructure Of Mica Glass-Ceramics And Interface Reactions Between Mica Glass-Ceramics And Bone, W. Holand, W. Gotz, G. Carl, W. Vogel

Cells and Materials

This review paper characterizes glass-ceramics containing mica as main crystal phase. The phase formation reactions in dependence of the chemical composition and the microstructure are shown. Microstructure of mica glass-ceramics has been studied by electron replica and scanning electron microscopic (SEM) techniques.

Mica glass-ceramics have previously been developed in Si02-B20rA120rMgO-F--base glasses. The material is machinable because of the precipitation of micas of fluorophlogopite-type. Also, a machinable glass-ceramic for dental applications was developed based on KMg2_5(Si40 10)F2-micas. We developed mica glass-ceramics in the Si02-Al20rMgO-NaiO-K20-F glass system. Phase formation within these glasses was observed by SEM. A double controlled nucleation and crystallization …

Apatite - Cholesterol Agglomerates In Human Atherosclerotic Lesions, Sara Sarig, Danielle Hirsch, Reuven Azoury, Teddy A. Weiss, Iony Katz, Howard S. Kruth

Cells and Materials

The purpose of this study was to examine the ultrastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in glutaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scanning electron microscope analyses. These included secondary electron imaging, back scattering of primary electrons, energy dispersive X-ray analysis of selected spots followed by area mapping of calcium and phosphorus , and cathodoluminescence.

The information gathered from scanning of selected areas in the lesions by all the techniques …