The effects of co-delivery of BMSC-affinity peptide and rhTGF-β1 from coaxial electrospun scaffolds on chondrogenic differentiation

Electrospinning is a promising technology for the fabrication of scaffolds in cartilage tissue engineering. Two other important elements for tissue engineering are seed cells and bioactive factors. Bone marrowderived stem cells (BMSCs) and rhTGF-beta 1 are extensively studied for cartilage regeneration. However, little is known about scaffolds that can both specifically enrich BMSCs and release rhTGF-beta 1 to promote chondrogenic differentiation of the incorporated BMSCs. In this study, we first fabricated coaxial electrospun fibers using a polyvinyl pyrrolidone/bovine serum albumin/rhTGF-beta 1 composite solution as the core fluid and poly(e-caprolactone) solution as the sheath fluid. Structural analysis revealed that scaffold fibers were relatively uniform with a diameter of 674.4 +/- 159.6 nm; the core shell structure of coaxial fibers was homogeneous and proteins were evenly distributed in the core. Subsequently, the BMSCspecific affinity peptide E7 was conjugated to the coaxial electrospun fibers to develop a co-delivery system of rhTGF-beta 1 and E7. The results of H-1 nuclear magnetic resonance indicate that the conjugation between the E7 and scaffolds was covalent. The rhTGF-beta 1 incorporated in E7-modified scaffolds could maintain sustained release and bioactivity. Cell adhesion, spreading, and DNA content analyses indicate that the E7 promoted BMSC initial adhesion, and that the scaffolds containing both E7 and rhTGF-beta 1 (CBrhTE) were the most favorable for BMSC survival. Meanwhile, CBrhTE scaffolds could promote the chondrogenic differentiation ability of BMSCs. Overall, the CBrhTE scaffold could synchronously improve all three of the basic components required for cartilage tissue engineering in vitro, which paves the road for designing and building more efficient tissue scaffolds for cartilage repair. (C) 2014 Elsevier Ltd. All rights reserved.