An injectable glass polyalkenoate cement engineered for fracture fixation and stabilization

Glass polyalkenoate cements (GPCs) have potential as bio-adhesives due to their ease of application, appropriate mechanical properties, radiopacity and chemical adhesion to bone. Aluminium (Al)-free GPCs have been discussed in the literature, but have proven difficult to balance injectability with mechanical integrity. For example, zinc-based, Al-free GPCs reported compressive strengths of 63 MPa, but set in under 2 min. Here, the authors design injectable GPCs (IGPCs) based on zinc-containing, Al-free silicate compositions containing GeO2, substituted for ZnO at 3% increments through the series. The setting reactions, injectability and mechanical properties of these GPCs were evaluated using both a hand-mix (h) technique, using a spatula for sample preparation and application and an injection (i) technique, using a 16-gauge needle, post mixing, for application. GPCs ability to act as a carrier for bovine serum albumin (BSA) was also evaluated. Germanium (Ge) and BSA containing IGPCs were produced and reported to have working times between 26 and 44 min and setting times between 37 and 55 min; the extended handling properties being as a result of less Ge. The incorporation of BSA into the cement had no effect on the handling and mechanical properties, but the latter were found to have increased compression strength with the addition of Ge from between 27 and 37 MPa after 30 days maturation. Keywords: fracture fixation; distal radius fracture; germanium oxide; polyacrylic acid; injectable glass polyalkenoate cements; bovine serum albumin

An injectable glass polyalkenoate cement engineered for fracture fixation and stabilization

Glass polyalkenoate cements (GPCs) have potential as bio-adhesives due to their ease of application, appropriate mechanical properties, radiopacity and chemical adhesion to bone. Aluminium (Al)-free GPCs have been discussed in the literature, but have proven difficult to balance injectability with mechanical integrity. For example, zinc-based, Al-free GPCs reported compressive strengths of 63 MPa, but set in under 2 min. Here, the authors design injectable GPCs (IGPCs) based on zinc-containing, Al-free silicate compositions containing GeO2, substituted for ZnO at 3% increments through the series. The setting reactions, injectability and mechanical properties of these GPCs were evaluated using both a hand-mix (h) technique, using a spatula for sample preparation and application and an injection (i) technique, using a 16-gauge needle, post mixing, for application. GPCs ability to act as a carrier for bovine serum albumin (BSA) was also evaluated. Germanium (Ge) and BSA containing IGPCs were produced and reported to have working times between 26 and 44 min and setting times between 37 and 55 min; the extended handling properties being as a result of less Ge. The incorporation of BSA into the cement had no effect on the handling and mechanical properties, but the latter were found to have increased compression strength with the addition of Ge from between 27 and 37 MPa after 30 days maturation. Keywords: fracture fixation; distal radius fracture; germanium oxide; polyacrylic acid; injectable glass polyalkenoate cements; bovine serum albumin

A Novel Glass Polyalkenoate Cement for Fixation and Stabilisation of the Ribcage, Post Sternotomy Surgery: An ex-Vivo Study

This study investigates the use of gallium (Ga) based glass polyalkenoate cements (GPCs) as a possible alternative adhesive in sternal fixation, post sternotomy surgery. The glass series consists of a Control (CaO–ZnO–SiO2), and LGa-1 and LGa-2 which contain Ga at the expense of zinc (Zn) in 0.08 mol% increments. The additions of Ga resulted in increased working time (75 s to 137 s) and setting time (113 to 254 s). Fourier Transform Infrared (FTIR) analysis indicated that this was a direct result of increased unreacted poly(acrylic acid) (PAA) and the reduction of crosslink formation during cement maturation. LGa samples (0.16 wt % Ga) resulted in an altered ion release profile, particularly for 30 days analysis, with maximum Ca2+, Zn2+, Si4+ and Ga3+ ions released into the distilled water. The additions of Ga resulted in increased roughness and decreased contact angles during cement maturation. The presence of Ga has a positive effect on the compressive strength of the samples with strengths increasing over 10 MPa at 7 days analysis compared to the 1 day results. The additions of Ga had relatively no effect on the flexural strength. Tensile testing of bovine sterna proved that the LGa samples (0.16 wt % Ga) are comparable to the Control samples.

A Novel Glass Polyalkenoate Cement for Fixation and Stabilisation of the Ribcage, Post Sternotomy Surgery: An ex-Vivo Study

This study investigates the use of gallium (Ga) based glass polyalkenoate cements (GPCs) as a possible alternative adhesive in sternal fixation, post sternotomy surgery. The glass series consists of a Control (CaO–ZnO–SiO2), and LGa-1 and LGa-2 which contain Ga at the expense of zinc (Zn) in 0.08 mol% increments. The additions of Ga resulted in increased working time (75 s to 137 s) and setting time (113 to 254 s). Fourier Transform Infrared (FTIR) analysis indicated that this was a direct result of increased unreacted poly(acrylic acid) (PAA) and the reduction of crosslink formation during cement maturation. LGa samples (0.16 wt % Ga) resulted in an altered ion release profile, particularly for 30 days analysis, with maximum Ca2+, Zn2+, Si4+ and Ga3+ ions released into the distilled water. The additions of Ga resulted in increased roughness and decreased contact angles during cement maturation. The presence of Ga has a positive effect on the compressive strength of the samples with strengths increasing over 10 MPa at 7 days analysis compared to the 1 day results. The additions of Ga had relatively no effect on the flexural strength. Tensile testing of bovine sterna proved that the LGa samples (0.16 wt % Ga) are comparable to the Control samples.