Electrospinning and characteristics of bicomponent bone tissue engineering scaffolds

Abstract

Bone tissue engineering requires 3D scaffolds. Due to their structural similarity to the extracellular matrix of biological tissues and hence their positive effects on cell behaviour and tissue formation, scaffolds electrospun from biodegradable polymers have attracted great attention. Electrospinning is also amenable to the incorporation of biomolecules into fibers. This feature gives electrospun scaffolds a particular advantage as, with the incorporation of biomolecules such as growth factors, their high surface area will enable them to provide local and sustained delivery of biological signals for the seeded cells. Therefore, for bone tissue engineering, osteoinductive growth factors, such as recombinant human bone morphogenetic protein 2 (rhBMP-2), can be incorporated into electrospun scaffolds. On the other hand, osteoconductive fibers containing calcium phosphate (Ca-P) nanoparticles can be formed through electrospinning. In this investigation, to achieve balanced osteoconductivity and osteoinductivity for bone tissue engineering scaffolds, novel bicomponent scaffolds were produced through dual-source dual-power electrospinning. One scaffold component was emulsion electrospun D,L-PLA nanofibers containing rhBMP-2 and the other component was electrospun Ca-P/PLGA nanocomposite fibers. Through process optimization, both types of fibers were evenly distributed in bicomponent scaffolds. The mass ratio between the two fibrous components was 1:1. In the systematic study, when conditions for the nanocomposite component were fixed, different emulsions were used for rhBMP-2/D,L-PLA fibers in order to vary the rhBMP-2 release rate. When the conditions for the emulsion electrospun component were fixed, PLGA with different GA:LA ratios was used for Ca-P/PLGA fibers. Using various techniques, the structure and properties of the two fibrous components and those of the bicomponent scaffolds were studied. The effects of the electrospinning parameters were also assessed.