Multifunctional zinc ion doped sol – gel derived mesoporous bioactive glass nanoparticles for biomedical applications

Abstract

Mesoporous bioactive glasses have been widely investigated for applications in bone tissue regeneration and, more recently, in soft tissue repair and wound healing. In this study we produced mesoporous bioactive glass nanoparticles (MBGNs) based on the SiO2–CaO system. With the intention of adding subsidiary biological function, MBGNs were doped with Zn2+ ions. Zn-MBGNs with 8 mol% ZnO content were synthesized via microemulsion assisted sol-gel method. The synthesized particles were homogeneous in shape and size. They exhibited spherical shape, good dispersity, and a size of 130 ± 10 nm. The addition of zinc precursors did not affect the morphology of particles, while their specific surface area increased in comparison to MBGNs. The presence of Zn2+ ions inhibited the formation of hydroxycarbonate apatite (HCAp) on the particles after immersion in simulated body fluid (SBF). No formation of HCAp crystals on the surface of Zn-MBGNs could be observed after 14 days of immersion. Interestingly, powders containing relatively high amount of zinc released Zn2+ ions in low concentration (0.6–1.2 mg L−1) but in a sustained manner. This releasing feature enables Zn-MBGNs to avoid potentially toxic levels of Zn2+ ions, indeed Zn-MBGNs were seen to improve the differentiation of osteoblast-like cells (MG-63). Additionally, Zn-MBGNs showed higher ability to adsorb proteins in comparison to MBGNs, which could indicate a favourable later attachment of cells. Due to their advantageous morphological and physiochemical properties, Zn-MBGNs show great potential as bioactive fillers or drug delivery systems in a variety of applications including bone regeneration and wound healing.

Effect of Cu- and Zn-Doped Bioactive Glasses on the In Vitro Bioactivity, Mechanical and Degradation Behavior of Biodegradable PDLLA Scaffolds

“…As described above, the stronger apatite inhibition in Zn-doped glasses compared to Cu-doped glasses is originated by the difference of intermolecular forces and bond geometries of Cu and Zn in the glass network, which generates more stable glass structures with lesser dissolution and leaching activity for Zn-doped glasses [22]. Other studies have discussed that the strong inhibition of the apatite formation caused by Zn doping is due to the presence of Zn 2+ ions in the active growth site of apatite which decelerate its crystallization [63,64]. The effect of both the incorporation of bioactive glass particles into PDLLA scaffolds and the type of metal-doped glass on apatite formation upon immersion in SBF was evaluated using SEM.…”

Strontium- and Cobalt-Doped Multicomponent Mesoporous Bioactive Glasses (MBGs) for Potential Use in Bone Tissue Engineering Applications

“…The initial types of BGs were synthesized by using a simple melt-quenching method; however, the high temperatures applied to prepare such glasses (typically around 1500 • C) are considered a critical limitation when incorporation of biomolecules into BGs is a goal to achieve an improvement in biological outcomes [5,6]. On the contrary, sol-gel glasses could be synthesized at lower temperatures and provide better opportunities for drug delivery strategies [7][8][9]. Glasses obtained by conventional sol-gel processes typically exhibit an inherent nanoporosity with quite a broad size distribution, which is not very suitable for drug delivery purposes.…”

Effects of Zn-Doped Mesoporous Bioactive Glass Nanoparticles in Etch-and-Rinse Adhesive on the Microtensile Bond Strength

“…As shown in Figure 3 , the concentrations of the released Si 4+ , PO 4 3− , Ca 2+ , and Zn 2+ increased over time in almost all the groups. In the DA-1.0% MBN-Zn group, the concentration of the released Ca 2+ increased until 7 days and subsequently decreased as Zn 2+ binds with PO 4 3− and Ca 2+ to form calcium Zn phosphate in an aqueous solution [ 45 ].…”

“…An apatite peak (JCPDS #9-0432) was only observed on DA-1.0% MBN-Zn as Zn 2+ binds with PO 4 3− and Ca 2+ to form calcium Zn phosphate in an aqueous solution. It could be assumed that Zn 2+ facilitates the formation of a ZnO rich layer that will permit Ca and P deposits and further remineralization [ 45 ].…”