Potential of electrospun chitosan fibers as a surface layer in functionally graded GTR membrane for periodontal regeneration

HAp (Hydroxyapatite) and α-TCP (alpha tribasic calcium phosphate) are non-toxic to human cells and, thus, have been studied for applications as biomaterials. HAp is a bioactive material that is not readily absorbed by the body; it offers both high strength and better tissueadhesive properties than α-TCP. In contrast, α-TCP is highly bioabsorbable; it is quickly absorbed by the body, and, therefore, for example, disappears before bone is completely replaced. If porous beads could be fabricated that would take advantage of the useful properties of α-TCP and HAp, they could be used as excellent scaffolds for cultivating cells. In the present study, ceramic beads with α-TCP at the center were fabricated and coated with a functionally graded film of HAp. A scaffold based on this configuration would be expected to have the following characteristics: good cell adhesion; strong beads; and a rate of absorption into the body that would be easy to control. In addition, to accelerate the formation of porous structure, some acid solutions were used to dissolve the beads surface layer and to penetrate pores toward inside of the bead. HAp formation through hydrolytic reaction seemed to be promoted by these acid solutions.

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3 D nano bilayered spatially and functionally graded scaffold impregnated bromelain conjugated magnesium doped hydroxyapatite nanoparticle for periodontal regeneration

Journal of the Mechanical Behavior of Biomedical Materials ◽

10.1016/j.jmbbm.2020.103822 ◽

2020 ◽

Vol 109 ◽

pp. 103822

Author(s):

Ekambaram Shoba ◽

Rachita Lakra ◽

Manikantan Syamala Kiran ◽

Purna Sai Korrapati

Keyword(s):

Periodontal Regeneration ◽

Functionally Graded

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Toughness Enhancement of Al2O3/Ce-TZP Functionally Graded Materials by Annealing in Inert Atmosphere

Materials Science Forum ◽

10.4028/www.scientific.net/msf.492-493.699 ◽

2005 ◽

Vol 492-493 ◽

pp. 699-704 ◽

Cited By ~ 1

Author(s):

Jef Vleugels ◽

Chao Zhao ◽

Omer Van der Biest

Keyword(s):

Surface Layer ◽

Functionally Graded Materials ◽

Inert Atmosphere ◽

Functionally Graded ◽

Pressureless Sintering ◽

Graded Materials ◽

Gradient Layer ◽

Annealing Cycle ◽

Toughness Enhancement ◽

Annealing Experiments

CeO2-stabilised ZrO2-based functionally graded materials (FGMs) can be successfully produced using electrophoretic deposition and pressureless sintering in air. A cylindrical Al2O3/ZrO2 FGM, for instance, shows an ideal structure for applications such as drill blanks. It has a central hole with a diameter less than 0.5 mm, a tough Ce-ZrO2 core with a diameter of about 3 mm, a gradient layer of about 1 mm, and a hard Al2O3-rich surface layer. The Ce-ZrO2 core shows a Vickers hardness between 10 and 11 GPa and an excellent toughness (>10 MPa m1/2). In the gradient layer, hardness and toughness vary continuously along the radius. The Al2O3-rich surface layer has a hardness of 15.2 GPa but a modest toughness of 2 MPa m1/2. Annealing experiments of the air-sintered FGM in inert atmosphere (Ar + 5 vol % N2) allows a significant toughness enhancement, especially in the surface layer (up to 8 MPa m1/2). The experimental results indicate that a proper controlled reduction of the Ce-TZP phase allows a modification of the toughness of the Ce-TZP phase. The influence of the annealing cycle on the properties of the FGM are reported and elucidated.

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Functionally graded porous ceramics with dense surface layer produced by freeze-casting

Ceramics International ◽

10.1016/j.ceramint.2011.04.119 ◽

2011 ◽

Vol 37 (8) ◽

pp. 3717-3722 ◽

Cited By ~ 22

Author(s):

Changqing Hong ◽

Jiancong Du ◽

Jun Liang ◽

Xinghong Zhang ◽

Jiecai Han

Keyword(s):

Surface Layer ◽

Porous Ceramics ◽

Functionally Graded ◽

Freeze Casting

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Microstructural Analysis of Sintered Gradient Materials Based on Distaloy SE Powder

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0104 ◽

2016 ◽

Vol 61 (2) ◽

pp. 613-620

Author(s):

K. Zarębski ◽

M. Nykiel

Keyword(s):

Surface Layer ◽

Cross Section ◽

Microstructural Analysis ◽

Functionally Graded ◽

Gradient Materials ◽

The Core ◽

Graded Structure ◽

Die Filling ◽

Manufactured Products ◽

Different Types

Abstract The study describes the microstructural analysis of cylindrically-shaped functionally graded products sintered from iron powder with scheduled graded structure on the cross-section running from the core to the surface layer of the sinter. Different types of structure were produced using Distaloy SE powder in two compositions - one without the addition of carbon, and another with 0.6wt% C. Two methods were used to fill the die cavity and shape the products. The first method involving a two-step compaction of individual layers. The second method using an original technique of die filling enabled the formation of transition zone between the outer layer and the core still at the stage of product shaping. As part of microstructural analysis, structural constituents were identified and voids morphology was examined. Studies covered the effect of the type of the applied method on properties of the graded zone obtained in the manufactured products

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Formation of a Ti-Al2O3 functionally graded surface layer on a Ti substrate with the use of ultrafine particles

Functionally Graded Materials 1996 ◽

10.1016/b978-044482548-3/50042-1 ◽

1997 ◽

pp. 251-256

Author(s):

A. Otsuka ◽

H. Tanizaki ◽

M. Niiyama ◽

K. Iwasaki

Keyword(s):

Surface Layer ◽

Ultrafine Particles ◽

Functionally Graded

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Fabrication of Nanostructured Gradient Tungsten-Cobalt Alloy Using Carbon Deficiency Powder

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.386.370 ◽

2018 ◽

Vol 386 ◽

pp. 370-376

Author(s):

Maksim Dvornik ◽

Elena Mikhailenko

Keyword(s):

Surface Layer ◽

Hard Alloy ◽

Wide Temperature Range ◽

Cobalt Content ◽

Functionally Graded ◽

Powder Layer ◽

Maximum Hardness ◽

Cobalt Alloy ◽

Cobalt Deficiency ◽

Normal Carbon

A nanostructured functionally graded hard alloy was obtained by sintering at temperatures from 1350 to 1410 ° C of two-layer "green bodies", each consisting of layer of powder with normal carbon content (WC-15Co-0.4VC-0.4Cr2C3) and powder layer with deficit of carbon (WC-8Co-0.4VC-0.4Cr2C3). The formation of the η phase (Co3W3C) in the layer with cobalt deficiency causes the migration of cobalt to it and prevents the return of cobalt back in a wide temperature range of temperatures (1350-1410). The porosity of the resulting nanocrystalline hard alloy at 1410 ° C is reduced to 2%, and the maximum hardness of the surface layer with a low cobalt content (10%) reaches 1945HV.

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The Effect of Cross-linking Efficiency of Drug-Loaded Novel Freeze Gelated Chitosan Templates for Periodontal Tissue Regeneration

AAPS PharmSciTech ◽

10.1208/s12249-020-01708-x ◽

2020 ◽

Vol 21 (5) ◽

Author(s):

Syed Saad B. Qasim ◽

Liebert Parreiras Nogueria ◽

Amr S. Fawzy ◽

Umer Daood

Keyword(s):

Drug Loading ◽

Periodontal Regeneration ◽

Functionally Graded ◽

Cross Linking ◽

Doxycycline Hyclate ◽

Average Pore ◽

Innovative Strategies ◽

Defect Site ◽

Fingerprint Region ◽

Novel Concept

Abstract Innovative strategies for periodontal regeneration have been the focus of research clusters across the globe for decades. In order to overcome the drawbacks of currently available options, investigators have suggested a novel concept of functionally graded membrane (FGM) templates with different structural and morphological gradients. Chitosan (CH) has been used in the past for similar purpose. However, the composite formulation of composite and tetracycline when cross-linked with glutaraldehyde have received little attention. Therefore, the purpose of the study was to investigate the drug loading and release characteristics of novel freeze gelated chitosan templates at different percentages of glutaraldehyde. These were cross-linked with 0.1 and 1% glutaraldehyde and loaded with doxycycline hyclate. The electron micrographs depicted porous morphology of neat templates. After cross-linking, these templates showed compressed ultrastructures. Computerized tomography analysis showed that the templates had 88 to 92% porosity with average pore diameter decreased from 78 to 44.9 μm with increasing concentration. Fourier transform infrared spectroscopy showed alterations in the glycosidic segment of chitosan fingerprint region which after drug loading showed a dominant doxycycline spectral composite profile. Interestingly, swelling profile was not affected by cross-linking either at 0.1 and 1% glutaraldehyde and template showed a swelling ratio of 80%, which gained equilibrium after 15 min. The drug release pattern also showed a 40 μg/mL of release after 24 h. These doxycycline-loaded templates show their tendency to be used in a functionally graded membrane facing the defect site.

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A New Silver-Based Graded Composite as Electrical Contact Material

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.2616 ◽

2007 ◽

Vol 336-338 ◽

pp. 2616-2618 ◽

Cited By ~ 2

Author(s):

Lu Wang ◽

Yong Zhao ◽

X.T. Zhu ◽

Y. Wang

Keyword(s):

Surface Layer ◽

Metal Oxides ◽

Contact Surface ◽

Electrical Contact ◽

Functionally Graded ◽

Operating Parameters ◽

Contact Material ◽

Contact Materials ◽

Electrical Contact Material ◽

Graded Material

Silver metal oxides (Ag/MeO) are extensively used as electrical contact materials in switching systems. A contact material with ideal operating parameters is very difficultly fabricated by conventional manufacturing techniques. In this paper, a new electrical contact material characterized by graded distributions of different oxides in Ag matrix was fabricated in order to optimize the distributions of operating parameters in material bulk instead of to enhance synchronously properties of that on contact surface. Two selected metal oxides, NiO and SnO2, were doped into Ag matrices, of which one surface layer NiO 12wt% was doped and another SnO2 12wt%, and the concentrations of NiO and SnO2 were varied gradually in bulk. The electrical contact test results show that the average operating number of NiO doped surface layer of graded Ag composite as contact surface is 4600 under 20A current and 220V AC voltage without melted welding while that of samples doped uniformly with NiO is 2200 under the same testing conditions. However, the average loss of mass due to arc erosion of graded samples is higher than that of uniform samples. We conclude that the functionally graded material (FGM) concept has potential application for electric contact materials.

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