scholarly journals The Potential of Tantalum-Doped Mesoporous Bioactive Glasses for Hemostasis

Author(s):  
Andrew Mendonca

Synthesis and characterization of the first mesoporous bioactive glasses (MBGs) containing tantalum (Ta) are reported, alongside their potential as hemostats. A series of silica MBGs with the molar composition of (80-x)% Si, 15% Ca, 5% P and x% Ta, with x = 0 to 10, were synthesized by the sol-gel method. Increasing Ta content from 1 to 10 mol% caused a decrease in the surface area and pore volume of ~20% and ~35%, respectively, due to the increase in non-bridging oxygens and mismatch of thermal expansion coefficient which creates discontinuities in the ordered channel structure. However, the effect is not significant on the amount of ions released from the samples into deionized water, for short durations (<60 min). In a mouse tail cut model, a significant decrease (≥ 50%) in average bleeding time was found for Ta-MBGs compared to controls (commercial hemostat Arista® and a Ta-free MBG). There was no significance in hemolytic activity between plain blood and when MBG is present and cytotoxicity results show that increasing Ta content from 0 to 10% reduced MBG toxicity by more than 15%; this effect was visually confirmed by live/dead cell assays. Further studies are proposed to determine the mechanism of Ta involvement with the hemostatic process.

2021 ◽  
Author(s):  
Andrew Mendonca

Synthesis and characterization of the first mesoporous bioactive glasses (MBGs) containing tantalum (Ta) are reported, alongside their potential as hemostats. A series of silica MBGs with the molar composition of (80-x)% Si, 15% Ca, 5% P and x% Ta, with x = 0 to 10, were synthesized by the sol-gel method. Increasing Ta content from 1 to 10 mol% caused a decrease in the surface area and pore volume of ~20% and ~35%, respectively, due to the increase in non-bridging oxygens and mismatch of thermal expansion coefficient which creates discontinuities in the ordered channel structure. However, the effect is not significant on the amount of ions released from the samples into deionized water, for short durations (<60 min). In a mouse tail cut model, a significant decrease (≥ 50%) in average bleeding time was found for Ta-MBGs compared to controls (commercial hemostat Arista® and a Ta-free MBG). There was no significance in hemolytic activity between plain blood and when MBG is present and cytotoxicity results show that increasing Ta content from 0 to 10% reduced MBG toxicity by more than 15%; this effect was visually confirmed by live/dead cell assays. Further studies are proposed to determine the mechanism of Ta involvement with the hemostatic process.


2015 ◽  
Vol 789-790 ◽  
pp. 43-47
Author(s):  
Daniel Setsoafia ◽  
Peter Hing ◽  
Andrew Jung ◽  
Aminul Islam ◽  
Abul K. Azad ◽  
...  

A Composite oxide ionic conductor consisting of La10Si6O27(LASIO) and Ce0.9Gd0.1O1.95(GDC) was synthesized by a modified sol-gel method. The La10Si6O27powders prepared by modified sol-gel synthesis were coated with GDC gel and latter calcined to form a La10Si6O27- Ce0.9Gd0.1O1.95composite material. The structural and microstructural properties of the composite were investigated using powder XRD, SEM and TMA. EIS was conducted in air on the sintered pellets to evaluate the electrochemical performance of the pellets. The conductivity of the composite electrolyte at 973 K was 26 mS /cm which is two orders of magnitudes higher than that for the pure LASIO but lower than that of the GDC (30 mS/cm). The thermal expansion of the composite electrolyte is similar to that obtained for the LASIO.


2002 ◽  
Vol 126 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Junying Zhang ◽  
Zhongtai Zhang ◽  
Zilong Tang ◽  
Zishan Zheng ◽  
Yuanhua Lin

2014 ◽  
Vol 121 ◽  
pp. 20-29 ◽  
Author(s):  
Tim Van Gestel ◽  
Felix Hauler ◽  
Martin Bram ◽  
Wilhelm A. Meulenberg ◽  
Hans Peter Buchkremer

2003 ◽  
Vol 800 ◽  
Author(s):  
Brady J. Clapsaddle ◽  
Lihua Zhao ◽  
Alex E. Gash ◽  
Joe H. Satcher ◽  
Kenneth J. Shea ◽  
...  

ABSTRACTIn the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.


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