Novel Electrospun Bicomponent Scaffolds for Bone Tissue Engineering: Fabrication, Characterization and Sustained Release of Growth Factor

Abstract

ABSTRACTElectrospinning is a versatile technique for fabricating three-dimensional (3D) nanofibrous scaffolds and the scaffolds have been found to elicit desirable cellular behavior for tissue regeneration because the nanofibrous structures mimic the nanofibrous extracellular matrix (ECM) of biological tissues. From the material point of view, the ECM of bone is a nanofibrous nanocomposite consisting of an organic matrix (mainly collagen) and inorganic bone apatite nanoparticles. Therefore, for bone tissue engineering scaffolds, it is natural to construct nanofibrous nanocomposites having a biodegradable polymer matrix and nanosized bioactive bioceramics. Our previous studies demonstrated: (1) electrospun nanocomposite fiber loaded with calcium phosphate (Ca-P) were osteoconductive and could promote osteoblastic cell proliferation and differentiation better than pure polymer fibers; (2) The controlled release of recombinant human bone morphogenetic protein (rhBMP-2) from scaffolds provided the scaffolds with desired osteoinductivity. In the current investigation, novel bicomponent scaffolds for bone tissue engineering were produced using our established dual-source dual-power electrospinning technique to achieve both osteoconductivity and osteoinductivity. In the bicomponent scaffolds, one fibrous component was electrospun Ca-P/PLGA nanocomposite fibers and the other component was emulsion electrospun PDLLA nanofibers incorporated with rhBMP-2. Through electrospinning optimization, both fibers were evenly distributed in bicomponent scaffolds. The mass ratio of rhBMP-2/PDLLA fibers to Ca-P/PLGA fibers in bicomponent scaffolds could be controlled using multiple syringes. The structure and morphology of mono- and bicomponent scaffolds were examined. The in vitro release of rhBMP-2 from mono- and bicomponent scaffolds showed different release amount but similar release profile, exhibiting an initial burst release. Blending PDLLA with polyethylene glycol (PEG) could reduce the initial burst release of rhBMP-2.