Solubility Control of αTCP-HAp Functionally Graded Porous Beads in SBF for Biomaterial Use

2010 ◽  
Vol 638-642 ◽  
pp. 2021-2027
Author(s):  
Teruo Asaoka ◽  
Yuji Kajihata ◽  
Katsuko Furukawa ◽  
Takashi Ushida ◽  
Tetsuya Tateishi
Keyword(s):  
Body Fluid ◽  
Absorption Rate ◽  
Bone Cells ◽  
High Strength ◽  
Functionally Graded ◽  
The Body ◽  
Tissue Adhesive ◽  
Adhesive Properties ◽  
Living Body ◽  
Porous Beads

As excellent scaffolds for cultivating bone cells, porous beads of bioactive ceramics such as HAp, TCP are considered to be promising. HAp and α-TCP are well known as non-toxic bioceramics to human cells, but their behavior in living body fluid are different. HAp is bioactive material which has both high strength and better tissue-adhesive properties, but that is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable; it is quickly absorbed by the body, and, therefore, disappears before bone is completely replaced. To realize a composite which has suitable solubility in living body fluid, α-TCP/ HAp functionally graded porous beads were fabricated by the method of spheroidization in liquid nitrogen. This type of composite maintains the function of scaffold with sufficient strength up to growth of new bone, and after the growth, it is expected to absorbed completely in the body. In the present study, ceramic beads with α-TCP at the center were fabricated and coated with a functionally graded layer of HAp. By controlling the thickness of HAp layer, which could be realized by changing time of hydrolytic reaction, the absorption rate into the body would be easily controlled. In addition, to accelerate the formation of porous structure, some acid solutions were used to dissolve the beads surface and to penetrate pores toward inside of the beads. Observed surface and inner structure by SEM, also the measured change in absorption rate will be presented.

Study on Bone Cell Adaptability of α-TCP/HAp Functionally Graded Porous Beads for Biomaterials Application

2010 ◽  
Vol 76 ◽  
pp. 143-146
Author(s):  
S. Ohtake ◽  
T. Asaoka ◽  
K. Furukawa ◽  
T. Ushida ◽  
T. Tateishi
Keyword(s):  
Bone Cells ◽  
High Strength ◽  
Bone Cell ◽  
Functionally Graded ◽  
The Body ◽  
Tissue Adhesive ◽  
Adhesive Properties ◽  
Living Body ◽  
Porous Beads

Porous beads of bioactive ceramics such as HAp, TCP are considered to be promising as excellent scaffolds for cultivating bone cells. To realize this type of beads which maintains the function of scaffold with sufficient strength up to growth of new bone, and is expected to absorbed completely after the growth, a-TCP/ HAp functionally graded porous beads were fabricated. HAp is bioactive material which has both high strength and better tissue-adhesive properties, but that is not readily absorbed by the human body. On the contrary, a-TCP is highly bioabsorbable; it is quickly absorbed by the body, and, therefore, disappears before bone is completely replaced. Fabricated new beads are composed of a-TCP at the center and HAp at the surface, to control the solubility in living body. Bone cell adaptability of these beads were confirmed in vitro.

Fabrication of α-TCP, HAp Functionally Graded Porous Beads

2008 ◽  
Vol 57 ◽  
pp. 135-138
Author(s):  
Yuji Kajihata ◽  
Teruo Asaoka ◽  
Katsuko S. Furukawa ◽  
Takashi Ushida ◽  
T. Tateishi
Keyword(s):  
Surface Layer ◽  
High Strength ◽  
Functionally Graded ◽  
The Body ◽  
Acid Solutions ◽  
Bioactive Material ◽  
Hydrolytic Reaction ◽  
Rate Of Absorption ◽  
Porous Beads ◽  
Good Cell

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.

Application of α-TCP/HAp Functionally Graded Porous Beads for Bone Regenerative Scaffold

2012 ◽  
Vol 86 ◽  
pp. 63-69 ◽  
Author(s):  
A. Tamura ◽  
Teruo Asaoka ◽  
K. Furukawa ◽  
T. Ushida ◽  
T. Tateishi
Keyword(s):  
Blood Vessel ◽  
Bone Regeneration ◽  
Dissolution Rate ◽  
Surface Area ◽  
Functionally Graded ◽  
Living Body ◽  
Porous Beads

α-TCP/HAp functionally graded porous beads were prepared for use as a scaffold for bone regeneration. In this research, porous beads which have compositionally graded layer, from TCP of inner area to HAp of surface area, were fabricated. It is known that the dissolution rate of TCP is fast in compare with that of HAp in living body, thus the inner area would dissolve prior to the surface area. These beads to allow the penetration of cells and blood vessel into the inner area of beads following new bone regeneration. At present, conditions to fabricate the functionally graded porous beads have been established already, and experiments using cells [MC3T3-E1] are in progress.

Numerical modelling of functionally graded adherends

2020 ◽  
pp. 095440622096769
Author(s):  
MQ dos Reis ◽  
RJC Carbas ◽  
EAS Marques ◽  
LFM da Silva
Keyword(s):  
Joint Strength ◽  
Adhesive Bonding ◽  
Adhesive Layer ◽  
High Strength ◽  
Lap Joints ◽  
Bond Line ◽  
Functionally Graded ◽  
Metal Alloys ◽  
Adhesive Properties ◽  
Main Research

The development of lighter structures and materials has been one of the main research concerns of the transportation industry during the last decade, driven by the necessity to decrease fuel consumption and emissions. Therefore, the use of several different new lightweight materials, such as special metal alloys, reinforced polymers and new advanced composite materials has been explored, leading to optimized structures which combine these novel materials. To manufacture these multi-material structures, adhesive bonding is one of best joining techniques available, as fasteners add weight to the structure and require holes to be drilled and welding is not easily applicable to reinforced plastics, composites and some high strength metal alloys. However, adhesive bonding also presents some limitations that need to be considered, such as the appearance of singularities and the resultant stress concentration at the edges of the bond line, which result in a reduction of the joint strength. In order to mitigate this effect, several techniques have been proposed, being the use of functionally graded adherends one of them. Functionally graded adherends consist in an adherend where the mechanical properties gradually change throughout the material, usually in the thickness or length direction. The present work introduces the concept of a layered functionally graded adherend, varying the flexibility of each layer through the thickness direction. Different ratios of stiffness variation, combined with different adhesive properties, were numerically evaluated for single lap joints, comparing the stress distribution of the adhesive layer and the resultant joint strength, using cohesive zone modelling. Moreover, an optimization process of typical graded material properties, where different distribution laws that consider material weight and strength are considered, is presented.

Computational prediction of small molecules with predicted binding to FGFR3 and testing biological effects in bone cells

2021 ◽  
pp. 153537022110021
Author(s):  
Subburaman Mohan ◽  
Karthikeyan Muthusamy ◽  
Selvaraman Nagamani ◽  
Chandrasekhar Kesavan
Keyword(s):  
Bone Formation ◽  
Small Molecules ◽  
Density Functional ◽  
Absorption Rate ◽  
Oral Absorption ◽  
Bone Cells ◽  
Biological Effects ◽  
Dynamics Simulation ◽  
Molecular Stability

Activating anabolic receptor-mediated signaling is essential for stimulating new bone formation and for promoting bone healing in humans. Fibroblast growth factor receptor (FGFR) 3 is reported to be an important positive regulator of osteogenesis. Presently, recombinant proteins are used to stimulate FGFR3 function but have limitations for therapy due to expense and stability. Therefore, there is a need for identification of novel small molecules binding to FGFR3 that promote biological function. In silico molecular docking and high-throughput virtual screening on zinc database identified seven compounds predicted to bind to an active site within the βCʹ-βE loop, specific to FGFR3. All seven compounds fall within an acceptable range of ADME/T properties. Four compounds showed a 30–65% oral absorption rate. Density functional theory analysis revealed a high HOMO-LUMO gap, reflecting high molecular stability for compounds 14977614 and 13509082. Five compounds exhibited mutagenicity, while the other three compounds presented irritability. Computational mutagenesis predicted that mutating G322 affected compound binding to FGFR3. Molecular dynamics simulation revealed compound 14977614 is stable in binding to FGFR3. Furthermore, compound 14977614, with an oral absorption rate of 60% and high molecular stability, produced significant increases in both proliferation and differentiation of bone marrow stromal cells in vitro. Anti-FGFR3 treatment completely blocked the stimulatory effect of 14977614 on BMSC proliferation. Ex vivo treatment of mouse calvaria in organ culture for seven days with 14977614 increased mineralization and expression levels of bone formation markers. In conclusion, computational analyses identified seven compounds that bind to the FGFR3, and in vitro studies showed that compound 14977614 exerts significant biological effects on osteogenic cells.

Of the Movement of Worms

1950 ◽  
Vol 27 (1) ◽  
pp. 29-39 ◽  
Author(s):  
GARTH CHAPMAN
Keyword(s):  
Hydrostatic Pressure ◽  
Closed System ◽  
Body Fluid ◽  
The Body ◽  
Cross Sectional ◽  
Working Length ◽  
Cylindrical Form ◽  
Maximum Thrust

Four aspects of the functioning of a fluid-filled cylindrical animal have been examined, viz.: (I) the role of the body fluid as a skeleton for the interaction of the longitudinal and circular muscles of which the animal must be composed; (2) the measurement of the maximum thrust which the animal can exert by measurement of its internal hydrostatic pressure; (3) the application of the force to the substratum and the part played by friction; (4) the relation between the changes in dimensions of the animal and the working length of the muscles. Under (1) the necessity for a longitudinal and circular construction has been shown and the necessity for a closed system emphasized. Under (2) the pressure exerted on the body fluid by the contraction of the longitudinal and circular muscles is discussed, and from their cross-sectional areas it is shown to be probable that when contracting maximally in Lumbricus they are not balanced, but that the longitudinals are about ten times as strong as the circulars. Under (3) it is shown that the strength of an animal as measured by its internal hydrostatic pressure is sufficient to account for its customary activities. Use which may be made of the longitudinals during burrowing is pointed out. Under (4) it is shown to be mechanically sound for burrowing animals of cylindrical form to be ‘fat’, but that a ‘thin’ animal is more efficient at progression.

Studies on the Physiology of Ascaris Lumbricoides

1952 ◽  
Vol 29 (1) ◽  
pp. 22-29
Author(s):  
A. D. HOBSON ◽  
W. STEPHENSON ◽  
A. EDEN
Keyword(s):  
Ascaris Lumbricoides ◽  
Body Fluid ◽  
External Medium ◽  
Chloride Concentration ◽  
The Body ◽  
Considerable Proportion ◽  
Limiting Factor ◽  
Inorganic Cations ◽  
Sodium And Potassium ◽  
Total Concentrations

The results obtained in this investigation are admittedly not as extensive as is desirable but they allow certain conclusions to be drawn. 1. The sodium and potassium contents of the body fluid of Ascaris lumbricoides are somewhat variable, but these variations do not seem to be dependent upon those of the external medium. 2. The calcium and magnesium contents of the body fluid are relatively constant and are not affected by those of the external medium. 3. The chloride concentration of the body fluid is closely related to and always remains lower than that of the external medium. 4. As shown in Table 2, there is a large gap between the total concentrations of inorganic cations and anions in the intestinal fluid of the pig. Presumably a considerable proportion of the inorganic cations are combined with organic anions, at present undetermined. Exposing the worms to saline media composed of chloride caused a large rise in the internal chloride concentration. This may well be a limiting factor in the life of the animals in such media, and the next step forward would seem to be the fuller analysis of the environment to which they are normally exposed.

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