Mesoporous bioactive glasses: structure characteristics, drug/growth factor delivery and bone regeneration application

Abstract

The impact of bone diseases and trauma in the whole world has increased significantly in the past decades. Bioactive glasses are regarded as an important bone regeneration material owing to their generally excellent osteoconductivity and osteostimulativity. A new class of bioactive glass, referred to as mesoporous bioglass (MBG), was developed 7 years ago, which possess a highly ordered mesoporous channel structure and a highly specific surface area. The study of MBG for drug/growth factor delivery and bone tissue engineering has grown significantly in the past several years. In this article, we review the recent advances of MBG materials, including the preparation of different forms of MBG, composition-structure relationship, efficient drug/growth factor delivery and bone tissue engineering application. By summarizing our recent research, the interaction of MBG scaffolds with bone-forming cells, the effect of drug/growth factor delivery on proliferation and differentiation of tissue cells and the in vivo osteogenesis of MBG scaffolds are highlighted. The advantages and limitations of MBG for drug delivery and bone tissue engineering have been compared with microsize bioactive glasses and nanosize bioactive glasses. The future perspective of MBG is discussed for bone regeneration application by combining drug delivery with bone tissue engineering and investigating the in vivo osteogenesis mechanism in large animal models.

Keywords: bioactivity; bone tissue engineering; drug/growth factor delivery; mesoporous bioglass scaffolds; osteogenesis.

Figure 1.

The concept of MBG for drug delivery and bone regeneration [40].

Figure 2.

Transmission electron microscopy images of (a) P123-induced MBG and (b) CTAB-induced MBG. P123 induced a more ordered mesopore structure than CTAB.

Figure 3.

Bioactive MBG nanospheres prepared by hydrothermal method.

Figure 4.

Porous MBG scaffolds with large pore size of around 300–500 µm prepared by the polyurethane sponge template method.

Figure 5.

Three-dimensional printing MBG scaffolds with ordered large pores (several hundred micrometres) and mesopores (5 nm).

Figure 6.

SEM image for MBG/alginate composite spheres for drug delivery and bone filler materials.

Figure 7.

Dexamethasone delivery in MBG scaffolds significantly enhanced bone-relative gene expression (ALP, BSP and Col I) of human osteoblasts. Red colour bars denote MBG and green colour bars denote DEX-MBG.

Figure 8.

Nanoapatite mineralization on the surface of three-dimensional MBG scaffold: (a) low magnification image; (b) high magnification image.

Figure 9.

BMSC attachment on silk-modified MBG scaffolds.

Figure 10.

The in vivo bone formation was evaluated by haematoxylin and eosin staining of MBG scaffolds in the femur defects of rats.