Composition and ultrastructure of PDLLA nanofibers with incorporated rhBMP-2 and rhVEGF(165) as scaffolds for tissue engineering

The objective of the present work is to fabricate and develop growth factor-PDLLA nano-composites by electrospinning into 2D fleece or 3D tubular scaffolds that can mimic the nature and function of the native extracellular matrix of bone tissue or artificial blood vessels. The bioactive growth factors I-125-rhVEGF(165), I-125-rhBMP-2 and the fibrous protein collagen were incorporated directly into the nascent PDLLA fiber during the electrospinning process. The morphology and distribution of the bioactive molecules in the electrospun fibers were investigated using TEM. The micro mechanical deformation was studied in tension tests using ESEM. The electrospun PDLLA nanofibers loaded with rhVEGF(165) and collagen showed a ductile behavior with necking and cold drawing deformation on stretching. The incorporation of rhVEGF(165), rhBMP-2 and collagen molecules into the scaffolds of PDLLA nanofibers could enhance cell attachment, reduce the scaffolds lifetime and promote angiogenesis and osteogenesis process, and thereby induce bone formation.