scholarly journals Engineering of Chitosan-Hydroxyapatite-Magnetite Hierarchical Scaffolds for Guided Bone Growth

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2321 ◽  
Author(s):  
Pistone ◽  
Celesti ◽  
Piperopoulos ◽  
Ashok ◽  
Cembran ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bone Growth ◽  
Cell Attachment ◽  
X Ray Diffraction ◽  
Culture Studies ◽  
X Ray ◽  
Support Cell ◽  
Chitosan Matrix

Bioabsorbable materials have received increasing attention as innovative systems for the development of osteoconductive biomaterials for bone tissue engineering. In this paper, chitosan-based composites were synthesized adding hydroxyapatite and/or magnetite in a chitosan matrix by in situ precipitation technique. Composites were characterized by optical and electron microscopy, thermogravimetric analyses (TGA), x-ray diffraction (XRD), and in vitro cell culture studies. Hydroxyapatite and magnetite were found to be homogeneously dispersed in the chitosan matrix and the composites showed superior biocompatibility and the ability to support cell attachment and proliferation; in particular, the chitosan/hydroxyapatite/magnetite composite (CS/HA/MGN) demonstrated superior bioactivity with respect to pure chitosan (CS) and to the chitosan/hydroxyapatite (CS/HA) scaffolds

Mechanical, microstructural properties and cell adhesion of Sr/Se-hydroxyapatite/graphene/polycaprolactone nanofibers

2020 ◽  
pp. 089270572091278 ◽  
Author(s):  
Reem Al-Wafi ◽  
SF Mansour ◽  
MK Ahmed
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Microstructural Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanofibrous Scaffolds ◽  
Transmission Electron ◽  
Fesem Micrographs

Electrospun nanofibrous scaffolds containing co-dopant of Sr/Se into carbonated hydroxyapatite has been synthesized in situ with graphene (G) nanosheets and carried on polycaprolactone at different contributions of G. The powder and the nanofibrous samples were investigated using X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy (FESEM). The FESEM micrographs show that the highest content of G (0.2 G) was formed in non-oriented/rough/cracked fibers with diameters around 0.3–0.4 µm at the maximum. The tensile strength of nanofibrous scaffolds was improved with the addition of G nanosheets and the maximum tensile strength of 0.2 G was around 6.39 ± 0.24 MPa, while the minimum cell viability ratio was about 94.4 ± 3.2% for the free G nanofibers. The in vitro attachment of HFB4 cell lines was investigated and it showed that nanofibrous scaffolds have induced cells to be proliferated and spread on the nanofibrous scaffolds’ surface. This behavior of cells growth encourages more investigations for these nanofibrous scaffolds to be promoted for clinical applications.

Preparation and Characterization of Fibrous Hydroxyapatite/Chitosan Nanocomposites with High Hydroxyapatite Dosage

2012 ◽  
Vol 457-458 ◽  
pp. 365-371 ◽  
Author(s):  
Cai Yun Zhang ◽  
Dai Yin Peng ◽  
Chuan Hua Lu ◽  
Xian Ping Wang ◽  
Qian Feng Fang
Keyword(s):  
Morphological Properties ◽  
In Vitro Tests ◽  
X Ray Diffraction ◽  
Permeable Membrane ◽  
X Ray ◽  
Chitosan Matrix ◽  
Transmission Electron

In this paper the hydroxyapatite fibers reinforced chitosan nanocomposites with high hydroxyapatite dosage (70~90 wt%) were synthesized by in-situ hybridization. The semi-permeable membrane was used to control the process of hybridization and morphology of hydroxyapatite. The compositional and morphological properties of nanocomposites were investigated by FTIR spectroscopy, X-ray diffraction, and transmission electron microscopy. The results showed that the hydroxyapatite were carbonated nanometer crystalline fibers with high aspect ratio (about 25) and dispersed uniformly in the nanocomposites. The high-resolution image indicated that the growth of nano-hydroxyapatite crystallites in the chitosan matrix preferred in the c-axis. The mechanical properties of these nanocomposites were enhanced dramatically and the compressive strength increases almost to 170MPa when the hydroxyapatite content is 70 wt%. The in vitro tests indicated that the composites have high bioactivity and degradation. These properties illustrated the potential application of this kind of nanocomposites for bone tissue engineering.

Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 191-203 ◽  
Author(s):  
F. Khormali ◽  
A. Abtahi ◽  
H. R. Owliaie
Keyword(s):  
Electron Microscopy ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
X Ray ◽  
Late Mesozoic ◽  
Southern Iran ◽  
Transmission Electron

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.

Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

scholarly journals Development of an Oxcarbazepine Solid Dispersion Using Skimmed Milk to Improve the Solubility and Dissolution Profile

2019 ◽  
Vol 11 (05) ◽  
Author(s):  
M. Shah ◽  
D. Patel
Keyword(s):  
Electron Microscopy ◽  
Solid Dispersion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Infra Red ◽  
Crystalline Nature ◽  
Skimmed Milk ◽  
Scanning Electron

Oxcarbazepine has low solubility and low oral bioavailability, so it’s a challenge to formulate suitable dosage form. In this present investigation, to improve the dissolution rate and solubility, skimmed milk is used as a carrier. Physical mixers were prepared using various drugs to carrier ratio and spray drying technology was used to develop solid dispersion with the carrier. Various techniques were used to characterize the solid dispersion immediately after they were made which includes differential scanning calorimetry, scanning electron microscopy, fourier transform infra- red spectroscopy, X-ray diffraction and in-vitro dissolution profiles. The differential scanning calorimetry thermograms of raw drug indicated of its anhydrous crystalline nature. In thermograms of solid dispersion, the characteristic peak was absent suggesting the change from crystalline nature to amorphous form. X-ray diffraction confirmed those results. X-ray diffraction results of raw drug showed highly intense peak characteristic of its crystalline nature where solid dispersion showed less intense, more diffused peak indicating the change in crystalline form. Fourier transforms infra-red spectroscopy studies showed there was no interaction between drug and carrier. Scanning electron microscopy support the amorphous nature of mixer. The whole formulation showed distinct enhancement in the drug release behavior and solubility. The optimum oxcarbazepine to skimmed milk ratio 1:3 enhances the in-vitro drug release by 3.5 fold and also show distinct increase in solubility. It was concluded that for improvement of solubility of poorly water soluble oxcarbazepine, skimmed milk powder as a carrier can be utilize very well.

Magnetic Pd/Fe3O4 Composite: Synthesis, Structure, and Catalytic Activity

2014 ◽  
Vol 67 (10) ◽  
pp. 1387 ◽  
Author(s):  
Shi-Qiang Bai ◽  
Lu Jiang ◽  
Sheng-Li Huang ◽  
Ming Lin ◽  
Shuang-Yuan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Reduction Process ◽  
Pd Nanoparticles ◽  
Pincer Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Transmission Electron

Composite Pd/Fe3O4 (1) was designed and synthesised by immobilization of tridentate pincer ligands with triethoxysilane groups on Fe3O4 nanoparticles, PdII complexation, and in-situ reduction process. The composite was characterised by transmission electron microscopy, scanning electron microscopy energy-dispersive X-ray spectroscopy, powder X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analysis. The composite featured Pd nanoparticles of ~2–4 nm, exhibited good thermal stability and hydrophilic property as well as excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in water.

Morphology of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2013 ◽  
Vol 457-458 ◽  
pp. 244-247
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflection Peak ◽  
Basal Reflection ◽  
Scanning Electron

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The morphology of MMT/MgCl2/TiCl4 catalyst and PE/MMT nanocomposites was investigated by scanning electron microscopy (SEM). It can be seen that MMT/MgCl2/TiCl4 catalyst remained the original MMT sheet structures and many holes were found in MMT and the morphology of PE/MMT nanocomposites is part of the sheet in the form of existence, as most of the petal structure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out to characterize all the samples. XRD results reveal that the original basal reflection peak of PEI1 and PEI2 disappears completely and that of PEI3 become very weak. MMT/MgCl2/TiCl4 catalyst was finely dispersed in the PE matrix. Instead of being individually dispersed, most layers were found in thin stacks comprising several swollen layers.

Bioactive Composite Materials for Bone Tissue Applications

2006 ◽  
Vol 514-516 ◽  
pp. 985-989
Author(s):  
B.J.M. Leite Ferreira ◽  
M.G.G.M. Duarte ◽  
M. Helena Gil ◽  
Rui N. Correia ◽  
J. Román ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bone Tissue ◽  
Tissue Repair ◽  
Body Fluid ◽  
In Vitro Bioactivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biodegradable Composite ◽  
Scanning Electron

Two materials with potential application in bone tissue repair have been developed: 1) a non-biodegradable composite based in a new methacrylic-co-acrylic matrix; and 2) a biodegradable composite based in a chitosan (Ch) matrix. Both matrices were reinforced with glass-ceramic particles of composition (mol%) 70 SiO2 – 30 CaO. The in vitro bioactivity of composites was assessed by soaking in simulated body fluid (SBF) for periods of up to 7 days at 37º C. X-ray diffraction (XRD) and scanning electron microscopy coupled with X-ray energy dispersive spectroscopy (SEM-EDS) were used for deposit identification after different soaking periods. Calcium phosphate particulate deposits were detected after 3 days of immersion, followed by growth and maturation towards apatite.

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