Herein we describe a method to fabricate submicron bioactive glass tubes using of sol-gel and co-axial electrospinning techniques for applications in bone tissue engineering. Heavy mineral oil and gel solution were delivered by two independent syringe pumps during the co-axial electrospinning process. Subsequently, submicron bioactive glass tubes were obtained by removal of poly(vinyl pyrrolidone) (PVP) and heavy mineral oil via calcination at 600 °C for 5 h. Tubular structure was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging. We examined the bioactivity of submicron bioactive glass tubes and fibers and evaluated their biocompatibility taking electrospun poly(ε-caprolactone) fibers – a bio-inactive material for comparison. The bioactivity of glass tubes was examined in a simulated body fluid (SBF) and these structures demonstrated the formation of hydroxyapatitelike minerals on both the outer and inner surfaces. In contrast, mineralization only occurred on their surface for bioactive glass solid fibers. Energy dispersive x-ray (EDX) data suggested that bioactive glass tubes had a faster induction of mineral formation compared that observed for the solid fibers. We demonstrate that the proliferation rate of mouse pre-osteoblastic MC3T3-E1 cells on bioactive glass tubes was comparable to that on solid fibers. We also show that bioactive glass tubes can be loaded with a model protein drug - bovine serum albumin (BSA) and that these structures, exhibit delayed release properties. The bioactivity of released lysozyme can be as high as 90.9%. Taken together, these data suggest that submicron bioactive glass tubes could hold great potential for use in bone tissue engineering as well as topical drug or gene delivery.
Xie J, Blough ER, Wang CH. Submicron bioactive glass tubes for bone tissue engineering. Acta Biomater. 2012;8:811-819. (doi: 10.1016/j.actbio.2011.09.009)