BMP-2-loaded silica nanotube fibrous meshes for bone generation

Abstract

Silica nanotube fibrous meshes were fabricated as multiple functional matrices for both delivering bone morphological protein-2 (BMP-2) and supporting osteoblast attachment and proliferation. The meshes were fabricated via a collagen-templated sol-gel route and consisted of tubular silica with open ends. BMP-2 was loaded to the meshes by soaking in BMP-2 solution. The meshes effectively enabled the attachment and proliferation of osteoblast MC3T3-E1 cells and delivered bioactive BMP-2 to stimulate cell differentiation. These results demonstrate the potential use of the meshes in bone generation applications.

Generation of microgrooved silica nanotube membranes with sustained drug delivery and cell contact guidance ability by using a Teflon microfluidic chip

“…It was found that the surface morphology of the samples depended on the type of microfluidic chips. In the case of a flat Teflon chip, the silica nanotube membranes exhibited a similar flat and smooth surface (figure 2(a)) with a porous and fibrous structure (inset) owing to the template role of the collagen fibrils, as was found in the previous studies [11, 14]. In the case of a microgrooved PDMS chip, no clear microgroove structure was found in figure 2(b).…”

“…Silica-coated collagen hybrid fibril hydrogels were fabricated by the method described previously [11, 14], by coating collagen fibrils with silica in a Stöber-type sol–gel system consisting of tetraethylorthosilicate (TEOS; 1 ml), ethanol (9 ml), water (9 ml) and ammonia (28%, 0.5 ml) at room temperature for 24 h. Subsequently, they were placed on either a microgrooved PDMS microfluidic chip or a microgrooved Teflon microfluidic chip (1 cm × 1 cm) and subjected to a loading force of 5 N at 50 °C for 2 h to produce the microgrooved silica-coated collagen hybrid fibril membranes. After calcination at 600 °C for 2 h, the collagen fibrils were completely removed from the silica-coated collagen hybrid fibril membranes and the microgrooved silica nanotube membranes were obtained in situ .…”

“…To evaluate the capability of microgrooved silica nanotube membranes for drug delivery, BMP-2 was selected as the model drug since it is a biological growth factor widely used for stimulating osteoblast differentiation [6, 14]. First, 100 μ l of 0.5 μ g ml −1 BMP-2 (Peprotech, Rocky Hill, NJ, USA) solution was added to the microgrooved silica nanotube membranes and then freeze-drying was performed to produce the corresponding BMP-2-loaded membranes containing 50 ng of BMP-2.…”

“…To date, many kinds of silica-derived forms that include spheres [8], membranes [6], xerogels [9], scaffolds [10] and nanotubes [11] have been synthesized and applied to stimulate bone regeneration. Among them, silica nanotubes have attracted special interest since they not only present hollow structural features for delivering various anti-cancer drugs [12], DNA [13] and biological growth factors [14], but also display a typical one-dimensional ECM-like fibrous structural feature to support cell attachment and proliferation [11, 14]. However, despite the prominence of silica nanotubes in biomedical applications, very little attention has been paid to the fabrication and applications of silica nanotubes with highly organized structure.…”

“…Microgrooved patterns are one of the most popular micropatterned surface topographies because of their well-defined and organized structure; they are easily directed by soft-/photo-lithographic techniques and strong cell contact guidance ability [7]. Collagen fibrils are one of the organic structural components of extracellular matrices in living tissue and exhibit a strong affinity for silica species via hydrogen bonding and electrical interactions for fabricating silica nanotubes [11, 14]. Therefore, when the collagen-based hydrogels are microgrooved, it is expected that the microgrooved collagen-based hydrogels could serve as an efficient template for in situ fabrication of free-standing and microgrooved silica nanotubes.…”