A new nanofiber fabrication technique based on coaxial electrospinning

In tissue engineering, nanofibrous scaffolds can achieve better biological responses than microfibrous scaffolds and electrospinning is a common method for producing fibrous scaffolds. However, not all biopolymers can be made into nanofibers through conventional electrospinning. The current investigation developed an innovative nanofiber fabrication technique based on coaxial electrospinning and used poly(hydroxybutyrate -co-hydroxyvalerate) (PHBV) as an example for achieving nanofibers. For obtaining PHBV nanofibers, core–shell structured fibers were fabricated first via coaxial electrospinning, with PHBV being the core and chitosan being the shell. The chitosan shell was then removed by washing electrospun scaffolds with water, leading to the formation of nanofibrous PHBV scaffolds. The PHBV nanofiber diameter was affected by the inner polymer (i.e., PHBV) solution concentration during coaxial electrospinning, which can be explained in terms of the coaxial electrospinning process and polymer solution viscosity. Compared to the approach of using a conductivity-enhancing salt in polymer solution to produce polymer nanofibers, the new technique not only eliminates the biocompatibility concerns but also provides a more effective way of reducing fiber diameters to the nano-size range. ► We develop a new nanofiber fabrication technique based on coaxial electrospinning. ► Removal of chitosan from PHBV-core/chitosan-shell fibers renders PHBV nanofibers. ► The diameter of the resultant PHBV nanofibers can be controlled. ► The new technique can be applied to other polymers.