Preparation of Adenosine-Loaded Electrospun Nanofibers and Their Application in Bone Regeneration

The possibility of composite nanofibers being able to regenerate bone is an attractive proposition. Adenosine, which occurs naturally in humans, has been shown to promote the osteogenic differentiation of mesenchymal stem cells (MSCs) and osteoprogenitor cells. In this study, electrospun nanofibers of poly(3-hydroxybutyrate-co-3-hydroxybutyrate) (PHBV) doped with adenosine were demonstrated to exhibit excellent capacity for bone regeneration, after optimization of the electrospinning process. The biomechanical properties, hydrophilicity, biocompatibility, cellular performance of the nanofibers and adenosine release profile from the composite nanofibers were evaluated. The osteogenic capacity of the composite nanofibers in vitro and in vivo was systematically studied. Electrospun adenosine/PHBV nanofibers demonstrated excellent tissue biocompatibility. In addition, adenosine-loaded/PHBV electrospun nanofibers exhibited substantial bone regeneration capacity in vitro and in critical-sized rabbit cranial defects in vivo, which was greater than that of bone marrow MSC (BMSC)-loaded/PHBV electrospun nanofibers. Additionally, BMSCs/PHBV electrospun nanofibers required culture with BMSCs for a period of time prior to surgery, whereas the adenosine/PHBV electrospun nanofibers could be implanted directly. To date, there is seldom no studies have evaluated the capability of bone regeneration of electrospun nanofibers doped with adenosine. Using a simple fabrication process and with a structure similar to that of natural extracellular matrix (ECM), electrospun adenosine/PHBV nanofibers exhibited excellent biocompatibility and osteogenic capacity. In addition, adenosine is inexpensive, straightforward to obtain and store and so holds huge practical potential in bone tissue engineering applications.