Dissolution, bioactivity behavior, and cytotoxicity of rare earth‐containing bioactive glasses (RE = Gd, Yb)

Abstract

Rare earth‐containing bioactive glasses (RE‐BGs) have been poorly explored in the biomaterials field, although RE has optical, nuclear, and magnetic properties that could be used in different biomedical applications. In order to verify whether these glasses can be promising as biomaterials, we studied the dissolution, bioactivity, and cytotoxicity of RE‐BGs based on the SiO2–Na2O–CaO–P2O5–RE2O3 (RE = Gd, Yb) system. The glasses were obtained by melting‐quenching and their particle size was determined by laser diffraction. Their dissolution behavior was studied in Tris‐HCl, while bioactivity was performed in simulated body fluid solution under physiological conditions during several periods. The cytotoxicity test was performed using glass‐derived conditioned medium and mesenchymal stem cell derived from deciduous teeth. The dissolution results showed that the glasses dissolved under two different kinetics, which are lower for rare earth‐containing glasses, due to the more covalent character of Si–O–RE bonds. The bioactivity results evidenced that all glasses showed bioactivity after 24 hours. However, gadolinium and ytterbium promoted a more calcium phosphate deposition, which contrasts with the slower dissolution kinetics of rare earth‐containing glasses. All the glasses were considered biocompatible, showing cell viability higher than 80%. The overall results showed that RE‐BGs are promising materials for applications that require bioactivity and/or biocompatibility.

Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

“…The systems were tested to estimate their biological properties and applications for regenerative medicine. In addition to conducting a bioactivity test of Gd 3+ /Yb 3+ -co-doped SiO 2 –Na 2 O–CaO–P 2 O 5 glass [ 27 ], the group of Borges had also a second goal to study the role of rare earth ions in the modification of glass structure [ 28 ].…”

Holmium-Containing Bioactive Glasses Dispersed in Poloxamer 407 Hydrogel as a Theragenerative Composite for Bone Cancer Treatment

“…Moreover, the glasses incorporation decreased the G′/G″ ratio compared to PL formulation, even though the viscoelastic behavior of all formulations are maintained ( Figure 4 B). Viscoelastic behavior is usually associated with G′ values 15 or 20-fold higher than G″, as Oshiro et al [ 30 ] discussed.…”

“…Besides, above the sol-gel transition, 37 °C, those formulations containing glasses displayed lower viscosity than the PL one. For PL-based formulations, viscoelastic behavior is usually associated with G′ values 15 or 20-fold higher than G″, as Oshiro et al [30] discussed. When the formulation is in In relation to the influence of temperature on viscosity profiles ( Figure 3B), all formulations showed similar behavior of G' modulus, that is, values in a 10 −1 mPa•s of magnitude before the sol-gel transition, followed by a sharp increase during the sol-gel transition (around 20 • C), reaching viscosity values in the magnitude of 10 6 mPa•s.…”

“…Besides, above the sol-gel transition, 37 • C, those formulations containing glasses displayed lower viscosity than the PL one. For PL-based formulations, viscoelastic behavior is usually associated with G values 15 or 20-fold higher than G , as Oshiro et al [30] discussed. When the formulation is in the hard-gel state, above 37 • C, a rheological characterization about gel stability is desired, which is performed through the analysis of G and G values at 37 • C as a function of the frequency, as shown in Figure 4A.…”

“…Glasses lack long-range periodic ordering, which is a consequence of their amorphous nature, enabling almost all the elements from the periodic table can be incorporated in the glass structure, including rare-earth [ 23 ]. The incorporation of rare-earth ions in bioactive glasses confers them new properties like optical, nuclear, and magnetic, enabling their applications in contrast agents in magnetic resonance [ 24 , 25 ], imaging diagnostics [ 26 , 27 ], brachytherapy (internal radiotherapy) seeds [ 28 , 29 ], among others [ 30 ]. Particular attention should be given to brachytherapy applications of bioactive glasses.…”