1 Effect of SrO incorporation on the morphology of Sol-Gel derived 58S bioactive glass 1 In the present study, the structural properties of SiO2-CaO-P2O5-SrO bioactive glass (BG) were investigated. Bioactive glass powder was synthesized through the sol-gel method and immersed in simulated body fluid (SBF) for a number of days to discover their structure. Precise analysis of the morphological structure of SiO2-CaO-P2O5-SrO bioactive glass employed scanning electron microscopy (SEM). The results established the formation of hydroxyapatite (HA) on the surface of bioactive glass powder. Additionally, it was found that, in day 14th, the hydroxyapatite surface is entirely covered in BGs and its aggregation is a little greater. It was shown that the apatite on the SiO2-CaO-P2O5-SrO bioactive glass surfaces had a spherical form. As a result, the microstructural analysis verified the bioactive nature of Sr-BG, supporting its use in bone-related biomaterial research. Evaluation techniques using the alkaline phosphatase (ALP) and MTT assays demonstrated that low strontium concentrations (2% and 5% SrO) stimulated the growth and differentiation of G292 osteoblastic cells. Lastly, the results show that BG-5Sr is a good fit for dental and bone tissue applications. 1 5 Firoozeh Niazvand Department of Anatomical Sciences, School of Medicine, Ilam University of Medical Sciences, Ilam Iran niazvandf@gmail.com Jalaladdin Hosseinzadeh Department of Biomedical Engineering, Central Tehran Branch, Islamic Azad University, Tehran Iran jalal.hosseinzadeh@iau.ac.ir Parisa Zahed Iran University of Medical Sciences, Finetech in Medicine Research Center, Iran University of Medical Sciences, Tehran Iran parisazahed1376@gmail.com Negar Azizabadi Department of Chemistry, Science and Research Branch, IAU, Tehran Iran Negarazizabadi@gmail.com Bioactive glass Strontium Microstructure Hydroxyapatite [1] M.S.N. Shahrbabak, F. Sharifianjazi, D. Rahban, A. Salimi, A Comparative Investigation on Bioactivity and Antibacterial Properties of Sol-Gel Derived 58S Bioactive Glass Substituted by Ag and Zn, Silicon 11(6) (2019) 2741-2751.##[2] Z. Ahmadi, F. Moztarzadeh, Synthesizing and Characterizing of Gelatin-Chitosan-Bioactive Glass (58s) Scaffolds for Bone Tissue Engineering, Silicon 10(4) (2018) 1393-1402.##[3] T. Kokubo, Bioactive glass ceramics: properties and applications, Biomaterials 12(2) (1991) 155-163.##[4] T. Ghasabpour, F. Sharifianjazi, L. Bazli, N. Tebidze, M. Sorkhabi, Bioactive glasses, ceramics, glass-ceramics and composites: State-of-the-art review and future challenges, Journal of Composites and Compounds 7(24) (2025).##[5] N. khosravi, A. Moradi, F. Sharifianjazi, K. Tavamaishvili, A. Bakhtiari, A. Mohammadi, A Review of samarium-containing bioactive glasses: biomedical applications, Journal of Composites and Compounds 7(22) (2025).##[6] V. Pal Singh Sidhu, R. Borges, M. Yusuf, S. Mahmoudi, S. Fallah Ghorbani, M. Hosseinikia, P. Salahshour, F. Sadeghi, M. Arefian, A comprehensive review of bioactive glass: synthesis, ion substitution, application, challenges, and future perspectives, Journal of Composites and Compounds 3(9) (2021) 247-261.##[7] A. Bakhtiari, A. Cheshmi, M. Naeimi, S.M. Fathabad, M. Aliasghari, A. Modarresi Chahardehi, S. Hassani, V. Elhami, Synthesis and characterization of the novel 80S bioactive glass: bioactivity, biocompatibility, cytotoxicity, Journal of Composites and Compounds 2(4) (2020) 110-114.##[8] G. Kaur, G. Pickrell, N. Sriranganathan, V. Kumar, D. Homa, Review and the state of the art: Sol–gel and melt quenched bioactive glasses for tissue engineering, Journal of Biomedical Materials Research Part B: Applied Biomaterials 104(6) (2016) 1248-1275.##[9] K. Zheng, A.R. Boccaccini, Sol-gel processing of bioactive glass nanoparticles: A review, Advances in Colloid and Interface Science 249 (2017) 363-373.##[10] M. Tylkowski, D.S. Brauer, Mixed alkali effects in Bioglass® 45S5, Journal of Non-Crystalline Solids 376 (2013) 175-181.##[11] I. Kansal, A. Reddy, F. Muñoz, S.-J. Choi, H.-W. Kim, D.U. Tulyaganov, J.M.F. Ferreira, Structure, biodegradation behavior and cytotoxicity of alkali-containing alkaline-earth phosphosilicate glasses, Materials Science and Engineering: C 44 (2014) 159-165.##[12] U. Pantulap, M. Arango-Ospina, A.R. Boccaccini, Bioactive glasses incorporating less-common ions to improve biological and physical properties, Journal of Materials Science: Materials in Medicine 33(1) (2021) 3.##[13] M. Modrák, M. Trebuňová, A.F. Balogová, R. Hudák, J. Živčák, Biodegradable Materials for Tissue Engineering: Development, Classification and Current Applications, Journal of Functional Biomaterials, 2023.##[14] M. Awais, A. Aizaz, A. Nazneen, Q.U. Bhatti, M. Akhtar, A. Wadood, M. Atiq Ur Rehman, A Review on the Recent Advancements on Therapeutic Effects of Ions in the Physiological Environments, Prosthesis, 2022, pp. 263-316.##[15] M. Khamehchi, A. Chkhenkeli, Influence of Ionic Size on the concentration of Ag+ and Zn2+ in Simulated Body Fluid: Modeling and Monte Carlo Simulation with Dental Applications, Journal of Composites and Compounds 6(21) (2024).##[16] J. Zhang, S. Zhao, Y. Zhu, Y. Huang, M. Zhu, C. Tao, C. Zhang, Three-dimensional printing of strontium-containing mesoporous bioactive glass scaffolds for bone regeneration, Acta Biomaterialia 10(5) (2014) 2269-2281.##[17] Y. Xiang, J. Du, Effect of Strontium Substitution on the Structure of 45S5 Bioglasses, Chemistry of Materials 23(11) (2011) 2703-2717.##[18] F. Khan Ahmadi, K. Mikeladze, Developments in Strontium-Doped Calcium Phosphate Composite Scaffolds for Dental Applications and Bone Tissue Engineering, Journal of Composites and Compounds 7(23) (2025).##[19] E. Bonnelye, A. Chabadel, F. Saltel, P. Jurdic, Dual effect of strontium ranelate: Stimulation of osteoblast differentiation and inhibition of osteoclast formation and resorption in vitro, Bone 42(1) (2008) 129-138.##[20] B. Kołodziejska, N. Stępień, J. Kolmas, The Influence of Strontium on Bone Tissue Metabolism and Its Application in Osteoporosis Treatment, International Journal of Molecular Sciences, 2021.##[21] M.-D. Yan, Y.-J. Ou, Y.-J. Lin, R.-M. Liu, Y. Fang, W.-L. Wu, L. Zhou, X. Yao, J. Chen, Does the incorporation of strontium into calcium phosphate improve bone repair? A meta-analysis, BMC Oral Health 22(1) (2022) 62.##[22] D.M. Black, D.E. Thompson, D.C. Bauer, K. Ensrud, T. Musliner, M.C. Hochberg, M.C. Nevitt, S. Suryawanshi, S.R. Cummings, Fracture Risk Reduction with Alendronate in Women with Osteoporosis: The Fracture Intervention Trial, The Journal of Clinical Endocrinology and Metabolism 85(11) (2000) 4118-4124.##[23] B. Bracci, P. Torricelli, S. Panzavolta, E. Boanini, R. Giardino, A. Bigi, Effect of Mg2+, Sr2+, and Mn2+ on the chemico-physical and in vitro biological properties of calcium phosphate biomimetic coatings, Journal of Inorganic Biochemistry 103(12) (2009) 1666-1674.##[24] Y.W. Gu, K.A. Khor, P. Cheang, In vitro studies of plasma-sprayed hydroxyapatite/Ti-6Al-4V composite coatings in simulated body fluid (SBF), Biomaterials 24(9) (2003) 1603-1611.##[25] R. Dziak, B.M. Yang, B.W. Leung, S. Li, N. Marzec, J. Margarone, L. Bobek, Effects of sphingosine-1-phosphate and lysophosphatidic acid on human osteoblastic cells, Prostaglandins, Leukotrienes and Essential Fatty Acids 68(3) (2003) 239-249.##[26] M. Nishimura, K. Yuasa, K. Mori, N. Miyamoto, M. Ito, M. Tsurudome, M. Nishio, M. Kawano, H. Komada, A. Uchida, Y. Ito, Cytological properties of stromal cells derived from giant cell tumor of bone (GCTSC) which can induce osteoclast formation of human blood monocytes without cell to cell contact, Journal of Orthopaedic Research 23(5) (2005) 979-987.##[27] C. Wu, Y. Zhou, C. Lin, J. Chang, Y. Xiao, Strontium-containing mesoporous bioactive glass scaffolds with improved osteogenic/cementogenic differentiation of periodontal ligament cells for periodontal tissue engineering, Acta Biomater 8(10) (2012) 3805-15.##[28] A.A. Gorustovich, T. Steimetz, R.L. Cabrini, J.M. Porto López, Osteoconductivity of strontium-doped bioactive glass particles: A histomorphometric study in rats, Journal of Biomedical Materials Research Part A 92A(1) (2010) 232-237.##[29] K. Fujikura, N. Karpukhina, T. Kasuga, D.S. Brauer, R.G. Hill, R.V. Law, Influence of strontium substitution on structure and crystallisation of Bioglass® 45S5, Journal of Materials Chemistry 22(15) (2012) 7395-7402.##[30] S. Fiorilli, G. Molino, C. Pontremoli, G. Iviglia, E. Torre, C. Cassinelli, M. Morra, C. Vitale-Brovarone, The incorporation of strontium to improve bone-regeneration ability of mesoporous bioactive glasses, Materials 11(5) (2018) 678.##[31] E. Gentleman, Y.C. Fredholm, G. Jell, N. Lotfibakhshaiesh, M.D. O'Donnell, R.G. Hill, M.M. Stevens, The effects of strontium-substituted bioactive glasses on osteoblasts and osteoclasts in vitro, Biomaterials 31(14) (2010) 3949-3956.##[32] J. Isaac, J. Nohra, J. Lao, E. Jallot, J.-M. Nedelec, A. Berdal, J.-M. Sautier, Effects of strontium-doped bioactive glass on the differentiation of cultured osteogenic cells, Eur Cell Mater 21(130) (2011) e43.##[33] J. Liu, S.C.F. Rawlinson, R.G. Hill, F. Fortune, Strontium-substituted bioactive glasses in vitro osteogenic and antibacterial effects, Dental Materials 32(3) (2016) 412-422.