An Injectable Glass Polyalkenoate Cement Engineered for Fracture Fixation and Stabilization

Abstract

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.

Incorporating Germanium Oxide into the Glass Phase of Novel Zinc/Magnesium-Based GPCs Designed for Bone Void Filling: Evaluating Their Physical and Mechanical Properties

“…Germanium (Ge) Oxide is an inorganic compound [ 25 ] which takes the role of a network former when incorporated into an ionomer glass and is theoretically capable of isomorphically replacing Si in the network [ 26 ]. Ge had been previously incorporated into borate-based ionomer glasses (BGG) by Zhang et al [ 27 , 28 ].…”

“…There was an increase in the setting and working time (handling properties) of the GPCs formulated from these glasses as a result of Ge incorporation, as this decreases the number of non-bridging oxygens (NBOs) in the glass network decreasing the working and setting times of the GPCs [ 29 ]. Dickey et al [ 27 , 30 , 31 ] reported on Ge-based ionomeric glasses and reported that glass reactivity decreased with Ge, ZrO 2 and Na 2 O incorporation, resulting in GPCs with extended working time (T w ) of up to 10 min, long setting time (T s ) up to 36 min, and compression strengths over 30 MPa after 30 days maturation [ 25 ]. Dickey et al [ 27 , 30 , 31 ] failed to evaluate whether these cements were injectable or not for use in vertebroplasty fixation.…”

“…Dickey et al [ 27 , 30 , 31 ] failed to evaluate whether these cements were injectable or not for use in vertebroplasty fixation. The work herein expands partly on the current authors’ previous work on zinc (Zn) silicate-based GPCs by evaluating the effect of incrementally replacing the Zn in the glass component with Ge [ 25 ]. In the authors’ previous study, Zn-GPCs containing up to 6 mol % Ge with incorporated bovine serum albumin (BSA) exhibited decreased working times (T w ) and setting times (T s ), with increased compressive strengths after 30 days maturation [ 25 ].…”

“…The work herein expands partly on the current authors’ previous work on zinc (Zn) silicate-based GPCs by evaluating the effect of incrementally replacing the Zn in the glass component with Ge [ 25 ]. In the authors’ previous study, Zn-GPCs containing up to 6 mol % Ge with incorporated bovine serum albumin (BSA) exhibited decreased working times (T w ) and setting times (T s ), with increased compressive strengths after 30 days maturation [ 25 ]. The resultant Ge-containing Zn-GPCs, then, were injectable, but set too slowly for purpose [ 25 ].…”

“…In the authors’ previous study, Zn-GPCs containing up to 6 mol % Ge with incorporated bovine serum albumin (BSA) exhibited decreased working times (T w ) and setting times (T s ), with increased compressive strengths after 30 days maturation [ 25 ]. The resultant Ge-containing Zn-GPCs, then, were injectable, but set too slowly for purpose [ 25 ].…”