Ionic Dissolution Products of Lithium-, Strontium-, and Boron-Substituted Silicate Glasses Influence the Viability and Proliferation of Adipose Stromal Cells, Fibroblasts, Urothelial and Endothelial Cells

While bioactive glasses (BaGs) have been studied mainly for bone applications, studies have also shown their potential for soft tissue engineering. Incorporating therapeutic ions, such as lithium (Li⁺), strontium (Sr²⁺), and boron (B³⁺) into the BaGs, has been found to promote angiogenesis and wound healing. However, a systematic study on the impact of Li⁺, Sr²⁺, B³⁺, and the other ions in the BaGs, has not been conducted on a wide range of cells. Although the interactions between the BaGs and cells have been studied, it is difficult to compare the results between studies and conclude the impact of BaGs between cell types due to the variability of culture conditions, cells, and materials. We aim to evaluate the dissolution behavior of Li-, Sr-, and B-substituted BaGs and the effects of their ionic dissolution products on the viability, proliferation, and morphology of multiple cell types: human adipose stromal cells (hASCs), human lung fibroblasts (cell line WI-38), human urothelial cells (hUCs), and human umbilical vein endothelial cells (HUVECs). In the dissolution study, the B-substituted glasses induced a higher increase in pH and released more ions than the silicate glasses. The undiluted BaG extracts supported the viability and proliferation of all the other cell types except the hUCs. Diluting the BaG extracts to 1:10 restored the viability of hUCs but induced distinctive morphological changes. Diluting the extracts more (1:100) almost fully restored the hUC morphology. To conclude, the ionic dissolution products of Li-, Sr-, and B-substituted BaGs seem beneficial for hASCs, WI-38, hUCs, and HUVECs, but attention must be paid to the ion concentrations.