Lithium-silicate sol–gel bioactive glass and the effect of lithium precursor on structure–property relationships

Abstract

This work reports the synthesis of lithium-silicate glass, containing 10 mol% of Li 2 O by the sol-gel process, intended for the regeneration of cartilage. Lithium citrate and lithium nitrate were selected as lithium precursors. The effects of the lithium precursor on the sol-gel process, and the resulting glass structure, morphology, dissolution behaviour, chondrocyte viability and proliferation, were investigated. When lithium citrate was used, mesoporous glass containing lithium as a network modifier was obtained, whereas the use of lithium nitrate produced relatively dense glass-ceramic with the presence of lithium metasilicate, as shown by X-ray diffraction, 29 Si and 7 Li MAS NMR and nitrogen sorption data. Nitrate has a better affinity for lithium than citrate, leading to heterogeneous crystallisation from the mesopores, where lithium salts precipitated during drying. Citrate decomposed at a lower temperature, where the crystallisation of lithium-silicate crystal is not thermodynamically favourable. Upon decomposition of the citrate, a solid-state salt metathesis reaction between citrate and silanol occurred, followed by the diffusion of lithium within the structure of the glass. Both glass and glass-ceramic released silica and lithium ions in culture media, but release rate was lower for the glass-ceramic. Both samples did not affect chondrocyte viability and proliferation.Graphical Abstract

Lithium‐Doped Silica‐Rich MIL‐101(Cr) for Enhanced Hydrogen Uptake

“…On the other hand, x Li‐RHA‐MIL‐101 displayed distinct behavior, where surface area and pore volume are significantly dependent on the content of Li + ion doping in RHA‐MIL‐101. It is evident that silanol bonds may show enhanced interactions with Li + ions, which may further facilitate efficient loading of Li + ion in RHA‐MIL‐101 . Moreover, the Li + ion may also occupy the available pores in the framework structure .…”

Sol–gel derived lithium-releasing glass for cartilage regeneration

“…Controlled delivery of therapeutic ions therefore represents an exciting prospect for "in situ" articular cartilage repair strategies and sol-gel glasses could be used as a delivery vehicle as their dissolution can be tailored as a function of their composition 15 . SiO2 -Li2O glass used in the present study was designed to deliver 5 mM of Li.…”

“…One of the benefits of using bioactive glass is that lithium can be delivered effectively in its active ionic form in lieu of conventional chemicals such as lithium chloride, and the delivery can be sustained as the glass dissolves [15]. In other studies, the stimulatory effects of GSK-3 antagonist on chondrogenic differntiation of human bone marrow derived stromal cells in 3-D micromass/pellet culture have been reported 9,10 .…”

“…The glasses were then dried (unsealed) at 130 • C using a 3-stage programme (60 • C for 20 h, 90 • C for 24 h and 130 • C for 40 h, ramp = 1 • C/min) and stabilised at 500 • C using a 2 stage programme (300 • C for 2 hours, 500 • C for 5 h, ramp = 1 • C/min). The stabilised glasses, which were amorphous 15 , were then ground and sieved (average diameter = 54.5 ± 20.1 μm).…”

Sol–gel bioglasses in dental and periodontal regeneration: A systematic review

“…Moreover, the porosity may work as a guide for blood vessels invasion and nutrient diffusion to the target . The sol–gel technique allows the incorporation of important therapeutic ions as Sr, Mg, or Li; moreover, these sol–gel derived BGs have been shown to regulate gene expression, protein synthesis, and cell‐mediated mineralization. It also offers the possibility to mix the glassy amorphous phase with some crystals to obtain combined materials with improved and joint mechanical properties.…”