Effect of crosslinking, hydroxyapatite addition, and fiber alignment to stimulate human mesenchymal stem cells osteoinduction in polycaprolactone-based electrospun scaffolds

Electrospinning is a versatile technique for producing composite scaffolds with nanostructure properties similar to the natural extracellular matrix. Biomaterials possessing mechanical, structural, and biological properties required for bone tissue engineering are a big challenge. However, the effect of fiber alignment, their mechanical properties, and chemical modifications on fibers are usually investigated individually. In this study, PCL/GE/HA scaffolds were electrospun in a static and drum rotatory collector to investigate the effects of alignment on the physicochemical properties of composite scaffolds. Furthermore, to achieve a stable composite with natural polymer gelatin (GE), a water-soluble, zero-length crosslinker (N-[3-dimethylaminopropyl]-N′-ethylcarbodiimide hydrochloride, EDC) was used to crosslink GE. Our results have outlined that the incorporation of GE, as well as crosslinking process, produced a hydrophilic biomaterial, improving wettability compared to pure polycaprolactone (PCL). In addition, the alignment reinforced the material, increasing mechanical strength. Biological tests showed that GE addition and the alignment allowed a better osteoinduction than pure random PCL.