Unlocking the potential of multicomponent mesoporous bioactive glass nanoparticles: An approach to enhanced ion therapy

This work presents the synthesis and characterization of a multicomponent mesoporous bioactive glass (MMBG) derived from the composition of 58S glass modified with copper, zinc, and boron. Morphological data revealed the presence of spherical particles with an average size of 616 nm and a specific surface area of 295 m2·g−1. X-ray diffractogram analysis confirmed the lack of long-range order in the MMBG, indicating the presence of a disordered vitreous structure characteristic of glass. The structural scenario of the bioactive glass MMBG reveals a characteristic configuration of borosilicate glasses, where the [BO4] polyhedra, along with SiO4 tetrahedra, constitute the backbone of the glassy matrix. Concerning zinc and copper ions, they function similarly to calcium in compensating for the remaining negative charges within the borosilicate network, behaving as typical network-modifying ions. The presence of these heavy ions, coupled with the formation of the borosilicate network in MMBG, led to a 20 % increase in density compared to 58S glass. Additionally, alterations in the chemical composition and structure of MMBG resulted in a reduction in molar volume compared to 58S, indicating a decrease in the volume occupied by one mole of oxygen in the glass matrix, thereby increasing the oxygen packing density. The pH studies reveal that changes in the chemical composition of MMBG did not compromise its chemical reactivity in aqueous environments. The capability of MMBG glass to act as a bioactive agent for ion therapy is evidenced by its ability to deliver Zn and Cu ions, as substantiated by the gradual disappearance of absorption in wavenumber range of 690–470 cm−1, attributed to the vibration of Zn-O and Cu-O bonds. Preliminary in vitro assay for bioactivity in SBF revealed that the formation of apatite layer on the surface of MMBG glass was notably thicker and denser compared to 58S glass. This result highlights the superior bioactive response of the MMBG bioactive glass, indicating its potential as an exceptionally favorable material for various biomedical applications.