The Influence of Cu²⁺ and Mn²⁺ Ions on the Structure and Crystallization of Diopside–Calcium Pyrophosphate Bioglasses

Abstract

The influence of two divalent cations, Cu 2+ and Mn 2+ , on the structure, sintering, and crystallization of glasses and glass-ceramics in the diopside-calcium pyrophosphate system (90 wt.% diopside (CaMgSi 2 O 6 ), 10 wt.% calcium pyrophosphate (Ca 2 P 2 O 7 )) was investigated. Glasses with 1, 3, and 5 wt% MnO or CuO additives were prepared by melt-quenching and characterized by XRD, 29 Si and 31 P NMR, DTA, and FTIR This revealed that the silicate network is predominantly coordinated in Q 2 (Si) units for all glasses, while phosphorus tends to inhabit an orthophosphate (Q 0 ) environment. All glasses had a high rate of bioactivity after immersion in simulated body fluid. A slight depolymerization was observed in the doped glasses leading to lower T g values in comparison with the parent glass. All glass-ceramics exhibited the formation of diopside as the primary crystalline phase after sintering at 850°C/1 h. In comparison with the parent glass, the doped glasses featured significantly larger processing windows (ΔT = T c -T g ), ensuring good sinterability. Further, with increasing doping levels, the glasses exhibited a gradual decrease in T p and ΔT, suggesting an increased tendency toward devitrification. All Cu-and Mn-containing glasses exhibited the formation of hydroxyapatite, making them good candidates for biomedical applications and tissue engineering.

Synthesis and bioactivity assessment of high silica content quaternary glasses withCa:Pratios of 1.5 and 1.67, made by a rapid sol‐gel process

“…The appearance of the twin peaks at ∼565 cm −1 and ∼ 601 cm −1 for the two glasses before SBF immersion can be attributed to the phosphate group , as the compositions include 6 mol % P. There is a well‐known intense phosphate band from HAp which also occurs at around 1090 cm −1 , which overlaps with the silicate bands noted above. Previous work by the authors on sol‐gel phosphate‐containing biolgasses also identified a significant shoulder around 1050 cm −1 , attributed to terminal ‐PO 3 end groups, and this may also contribute to the significant broadening of this peak . The small band at ∼870 cm −1 is attributed to a carbonate substitution at a phosphate site .…”

“…Medical, biotechnology, life sciences, and optical technologies are all important applications of glasses, and glasses were introduced as a biomaterial after the discovery of bioactive glass by Hench . Since then, tremendous progress has been made using different compositions, or by using various dopant ions . Different preparation techniques have been used to synthesis glass, but melt quenching and sol‐gel are the most common techniques to synthesize glass for tissue engineering .…”

Synthesis of Cu-containing Diopside through a One-Step Crystallization

“…For the same reason, the inoculation of diopside with monovalent elements [16] was also studied to improve the viability and degradability. Regarding its internal structure, the effect of addition of both manganese and copper on the biological properties of the diopside were also studied [17]. Incorporation of iron and magnesium for switching the magnetism in the structure of the diopside was also reported [18].…”