Tailoring the viscoelastic properties of injectable biocomposites: A spectroscopic assessment of the interactions between organic carriers and bioactive glass particles

Abstract

Injectable bioglass (BG) pastes were produced using a melt-quenched glass based on CaO-MgO-SiO 2 -Na 2 O-P 2 O 5 -CaF 2 and two organic carriers, namely polyethylene glycol (PEG) and glycerol (Gly). The interactions between the organic carriers and the surface of the BG particles were assessed by spectroscopic methods (Fourier Transform Infrared, Raman, as well as 29Si and 13C solid-state NMR spectroscopy) in order to understand their effects on the viscoelastic properties of the biocomposites. While pure physical interactions were detected between PEG and the surface of the BG particles, chemical bonding was observed between glycerol and BG, enhancing the network cross-linking degree. Accordingly, the BG network of Gly-BG pastes was more condensed (higher fraction of Q [3] units detected by Raman spectroscopy) in comparison to that of PEG-BG and bare BG. Such chemical interactions between the organic carrier and BG were shown to negatively affect the viscoelastic behaviour of the resulting pastes. Thus, the PEG-based biocomposite exhibited improved flowability in comparison to its analogous Gly-BG biocomposite.

Effect of Alumina Incorporation on the Surface Mineralization and Degradation of a Bioactive Glass (CaO-MgO-SiO2-Na2O-P2O5-CaF2)-Glycerol Paste

“…1.46 wt %. This can be explained by the fact that upon immersion of BG-gly into SBF, first glycerol should get dissolved; as some glycerol is chemically bonded to the surface of BG [ 10 ], one may speculate that the chemically bonded BG might be responsible for the lower mass loss observed for the BG-gly samples. In the case that the chemically bonded glycerol also gets leached into SBF (in time), the lower mass loss of BG-gly as compared to that of BG may be considered as a consequence of the lower dissolution rate of BG in BG-gly due to the presence of the surface-bonded glycerol.…”

“…The difference in the in vitro behavior between BG and BG-gly can be explained by structural features of the BG-gly paste. The results of our previous spectroscopic study on BG-gly [ 10 ] clearly indicate that glycerol chemically interacts with the surface of the BG particles. Typically, the reaction between gly and the BG surface can be described in a similar way as the reaction between siloxane bonds and alcohols, which was studied in the past by various researchers [ 25 , 26 ].…”

“…More recent experimental data clearly indicated the fact that the processability and bioactivity of the pastes can be adjusted by the organic carrier. In a recent case study, it was shown the occurrence of chemical bonding between the surface of bioactive glass particulates and glycerol (gly), whereas only physical interactions were detected in the case of organic carrier based on PEG [ 10 ].…”

“…The aim of present study was to elucidate the effect of alumina incorporation on the surface mineralization and degradation of bioglass (BG) and a bioglass-glycerol (BG-gly) paste. Within this context, the effect of the synthesis of BG in an alumina crucible (unlike in other reported studies, which used a Pt crucible [ 5 , 6 , 7 , 9 , 10 ]), as well as the effect of glycerol interaction with the BG surface on the bioactivity was carefully assessed via SBF tests and extensive structural analysis of the studied materials. It is shown that the synthesis condition of BG affects its network connectivity and consequently alters its bioactivity; moreover, the BG-gly sample exhibits strong chemical interactions between gly and the BG surface, which boost the bioactivity of the paste in comparison to that of the neat BG.…”

Organic-Silica Interactions in Saline: Elucidating the Structural Influence of Calcium in Low-Salinity Enhanced Oil Recovery

“…The influence of ionic strength and electrolyte composition on non-covalent adsorption of polar compounds at the aqueous electrolyte/silica interface is important in a wide range of commercial applications 1 , including drug delivery systems 2 , artificial bioglass bone implants 3 and low-salinity enhanced oil recovery (EOR) from sandstone reservoirs 4 , 5 . In low-salinity EOR, there is clear evidence that production from sandstone reservoirs is higher when the water used to sweep the reservoir and maintain pressure has salinity below ~5,000 ppm than when seawater (salinity ~36,500 ppm) is used 6 ; this phenomenon is termed the “low-salinity effect” (LSE).…”