Conjugated electrospinning toward a polycaprolactone scaffold simultaneously containing micro-/nano- fibers for potential biomedical application

The use of electrospun nanofibers to create a supportive scaffold for cell growth and tissue development has attracted intensive interest in the field of tissue engineering. In this study, a conjugated electrospinning system was designed and employed to fabricate a series of different polycaprolactone (PCL) scaffolds simultaneously containing both of microfibers and nanofibers. SEM images conformed the successful formation of micro-/nano- fibers in one scaffold by adjusting the polymeric concentrations. The PCL concentration was found to have dramatic effects on the diameter of as-generated fibers, and the mean diameter and crystallinity of electrospun PCL fibers decreased with the decreasing of PCL concentration, resulting in much lower mechanical properties. Compared with the pure PCL microfiber-constructed scaffold, the PCL micro-/nano- fiber scaffolds exhibited obviously decreased mean pore size, increased porosity. Interestingly, the PCL micro-/nano- fiber scaffolds were found to exhibit significantly increased Young’s modulus and ultimate stress than both of PCL nanofiber scaffold and PCL microfiber scaffold. In vitro cell characterization results indicated that the introduction of nanoscale fibers significantly enhanced cell adhesion, and proliferation of PCL micro-/nano- fiber scaffolds. Moreover, this enhancement became more pronounced as the average diameter of the nanoscale fibers decreased. Overall, our present study provides an effective strategy for generating PCL micro-/nano- fiber scaffolds with more appropriate structure and properties, which show great potential for tissue engineering application.