Fibrous delivery vehicles formed by dual-source dual-power electrospinning for the dual release of growth factors

Abstract

In bone tissue engineering, localized and controlled delivery of growth factors (GFs) can significantly enhance bone tissue regeneration. Electrospun fibers, which bear a structural resemblance to the extracellular matrix of biological tissues, have attracted great attention not only for their ability to elicit desirable cell behaviour but also for their capability of encapsulating GFs and releasing them in a controlled manner. In this investigation, bicomponent fibrous scaffolds for the dual delivery of GFs were formed through dual-source dual-power electrospinning. One scaffold component was emulsion electrospun polymer nanofibers containing recombinant human bone morphogenetic protein 2 (rhBMP-2) and the other component was emulsion electrospun polymer nanofibers containing basic fibroblast growth factor (bFGF). rhBMP-2 and b-FGF were labeled with rhodamine B and fluorescence isothiocyanate (FITC) fluorescent dyes, respectively. For obtaining controlled GF release rates, polymers for the fibrous components in scaffolds were carefully selected according to their degradation rates. When simultaneous dual release was investigated, PLGA (50/50) was used for both fibrous components. D,L-PLA or PLGA (75/25), which has a lower degradation rate, was used for fibers containing rhBMP-2 when a sequential release of GFs was investigated. Through electrospinning optimization, both fibers were evenly distributed in bicomponent scaffolds. Using various techniques, the structure and properties of each type of fibers in the scaffolds such as fiber diameter, core-shell structure and growth factor distribution were evaluated. The in vitro release behaviours of GFs from fibrous scaffolds were studied.