Dissolution behavior and bioactivity of lithium-doped 45S5 bioglass: An experimental and molecular dynamics simulation study

This study used molecular dynamics (MD) simulations and experimental analyses to evaluate lithium (Li)-doped 45S5 bioglass (45-L) for tissue engineering (TE) applications. Li2O was substituted for Na2O in the 45S5 bioglass composition with 0–20 mol%, then resulting in new materials labeled as 45-L0 to 45-L20. Atomic-scale characteristics were evaluated in terms of short- and medium-range structure. Short-range structure presented pair distribution function (PDF) and coordination number (CN) of the samples showing that the Li–O bonds were shorter in the structure due to the smaller ionic radius, and the CN was calculated to be 4.03. Additionally, the medium-range structure of the Li-doped BGs showed dominant non-bridging oxygens (NBOs) with negligible P–O–P bonds, while Li2O did not change the bond types significantly. Additionally, Qn analysis showed that the Li incorporation promoted the formation of Q3 species and increased network connectivity (NC) from 1.92 for 45-L0 to 1.96 for 45-L20. Moreover, Li2O enhanced structural density but was expected to reduce the dissolution of BGs. ICP-AES analysis showed that the release of Si4+ ions decreased with higher Li2O content. Meanwhile, SEM images showed a bioactive behavior of the 45-L5 sample while immersed in SBF solution for 14 days. Taken together, the integration of MD simulations, ICP-AES data and SEM showed an interesting balance of properties for moderate Li2O content, and especially the 45-L5 composition can be considered as a promising candidate for bone tissue regeneration applications.