Controlled release of bone morphogenetic protein 2 and dexamethasone loaded in core–shell PLLACL–collagen fibers for use in bone tissue engineering

Electrospun nanofibers mimic the native extracellular matrix of bone and have generated considerable interest in bone tissue regeneration. The aim of this study was to fabricate novel poly(l-lactide-co-caprolactone) (PLLACL), PLLACL/collagen nanofibers blended with bone morphogenetic protein 2 (BMP2) and dexamethasone (DEX) for controlled release during bone tissue engineering (BTE). The morphology, surface hydrophilicity, and mechanical properties of the PLLACL/collagen nanofibrous mats were analyzed by scanning electron microscopy and water contact angle and mechanical stability determination. The performance of the scaffolds was investigated in terms of the viability and morphology of human mesenchymal stromal cells (hMSC) on the nanofibrous mats. BMP2 and DEX were successfully incorporated into PLLACL/collagen nanofibers by means of blending or coaxial electrospinning and the PLLACL/collagen blended fibers proved useful for hMSC culture. Release of the two growth factors from PLLACL/collagen nanofibrous mats in vitro was investigated by UV spectrophotometry. The release profiles for core–shell nanofibers showed more controlled release of the growth factors compared with the blended electrospun fibers. The experimental results show that controlled release of BMP2 and DEX can induce hMSC to differentiate into osteogenic cells for bone tissue engineering. The results imply that PLLACL/collagen nanofibers encapsulating two drugs and/or proteins have great potential in bone tissue engineering.