The effect of tantalum incorporation on the physical and chemical properties of ternary silicon–calcium–phosphorous mesoporous bioactive glasses

Abstract

Synthesis and characterization of the first mesoporous bioactive glasses (MBGs) containing tantalum are reported here, along with their potential application as hemostats. Silica MBGs were synthesized using with the molar composition of (80‐x)% Si, 15% Ca, 5% P, and x% Ta. It was found that incorporation of >1 mol % Ta into the MBGs changes their physical and chemical properties. Increasing Ta content from 0 to 10 mol % causes a decrease in the surface area and pore volume of ~20 and ~35%, respectively. This is due to the increase in nonbridging oxygens and mismatch of thermal expansion coefficient which created discontinuities in the ordered channel structure. However, the effect is not significant on the amount of ions (Si, Ca, P, and Ta) released, from the sample into deionized water, for short durations (<60 min). In a mouse tail‐cut model, a significant decrease in bleeding time (≥50% of average bleeding time) was found for Ta‐MBGs compared to having no treatment, Arista, and MBG without Ta. Further studies are proposed to determine the mechanism of Ta involvement with the hemostatic process. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2229–2237, 2019.

Tantalum-containing mesoporous bioactive glass powder for hemostasis

“…BGs can be doped with ions such as strontium (Sr, to enhance in vivo bone formation), 22 magnesium (Mg, for stimulating bone formation), 22 zinc (Zn, for anti-inflammatory and antibacterial effects, and stimulating osteogenesis), 22 calcium (Ca, for enhancing hemostasis), 20 , 23 silver (Ag, for its antibacterial effect), 23 gallium (Ga, for hemostasis and antibacterial effect), 20 , 23 and tantalum (Ta, for its hemostatic potential). 23 , 24 Alongside the effect on the BGs properties, doping also alters the physical structures of these products. 25…”

“…In our previous study, 23 Ta was incorporated incrementally (0 to 10 mol%) into a Si-Ca-P MBG to produce a series of tantalum-containing MBGs (Ta-MBGs) and the effect of this on physical, chemical and hemostatic properties was determined. 23 Ta was chosen as a dopant to enhance the inherent hemostatic properties of Si-Ca-P MBG because tantalum oxide exhibits antibacterial and anti-inflammatory properties. 26–28 Tantalum oxide powder has been proposed for hemostasis, 26 but its use as a dopant in a Si-Ca-P MBG to enhance hemostasis of the silicate MBG was first proposed by the authors.…”

“…26–28 Tantalum oxide powder has been proposed for hemostasis, 26 but its use as a dopant in a Si-Ca-P MBG to enhance hemostasis of the silicate MBG was first proposed by the authors. 23 At low Ta contents, these Ta-MBGs displayed hexagonal mesoporous nanostructures, but as Ta increased above 1 mol%, the ordered hexagonal channels started showing discontinuities; 23 thought to be the result of an increase in the non-bridging oxygens (with increasing Ta mol% in the glass series) and mismatched coefficient of thermal expansion of Ta with other MBG components. 23 Ta-MBGs containing 10mol% Ta showed maximum disruption of the mesoporous ordered channels resulting in reduced surface area and pore volumes.…”

“…23 At low Ta contents, these Ta-MBGs displayed hexagonal mesoporous nanostructures, but as Ta increased above 1 mol%, the ordered hexagonal channels started showing discontinuities; 23 thought to be the result of an increase in the non-bridging oxygens (with increasing Ta mol% in the glass series) and mismatched coefficient of thermal expansion of Ta with other MBG components. 23 Ta-MBGs containing 10mol% Ta showed maximum disruption of the mesoporous ordered channels resulting in reduced surface area and pore volumes. 23 A preliminary small animal model included in this previous study using a mouse tail-bleed model confirmed the hemostatic potential of Ta-MBGs; the measured bleeding time reduced significantly (≥50% of average bleeding time) by the use of the Ta-MBGs compared to ‘no treatment’, an MBG of the same formula with no Ta doping, and also against a commercial hemostat, Arista™ (Bard Davol Inc., Rhode Island, USA), a starch-based hemostat.…”

“…23 Ta-MBGs containing 10mol% Ta showed maximum disruption of the mesoporous ordered channels resulting in reduced surface area and pore volumes. 23 A preliminary small animal model included in this previous study using a mouse tail-bleed model confirmed the hemostatic potential of Ta-MBGs; the measured bleeding time reduced significantly (≥50% of average bleeding time) by the use of the Ta-MBGs compared to ‘no treatment’, an MBG of the same formula with no Ta doping, and also against a commercial hemostat, Arista™ (Bard Davol Inc., Rhode Island, USA), a starch-based hemostat. 23 However, the amount of Ta incorporation (0.5-10 mol%) into the MBGs did not, in itself affect bleeding time indicating that the presence of small amounts of Ta was required to reduce bleeding time but increasing Ta doping did not reduce bleeding time further.…”