Blending salmon gelatin with polyvinylidene fluoride using coaxial electrospinning

Electrospinning is a technique that produces large quantities of nanofibers, that can be designed at the molecular level. Electrospun membranes can be designed to biomimic the chemical composition and morphological structure of the extracellular matrix. Here, we blend salmon gelatin with polyvinyl alcohol and chitosan, which are electrospun in a coaxial configuration with polyvinylidene fluoride, a piezoelectric polymer. We obtain membranes with two size distributions, a large nanofiber distribution with a mean diameter of 426 ±142 nm and a small nanofiber distribution with a diameter of 251 ±49 nm. Nanomechanical characterization of the large nanofibers reveals two Young's moduli peaks centered at 1.77 ±0.05 GPa and 209±126 MPa. Small nanofibers also show a two component mechanical moduli distribution centered at 565 ±115 MPa and 1.33±0.31 GPa. This characterization indicates that the larger nanofibers are made mainly of polyvinylidene fluoride, while the smaller distribution consists of polyvinyl alcohol with polyvinylidene fluoride. Raman spectroscopy ensures the presence of all four polymers within the final membrane. This could indicate that polyvinylidene fluoride and the polyvinyl alcohol blend are separating during the coaxial electrospinning process, although we do not rule out the presence of core-shell nanofibers. These membranes have potential applications as scaffold for tissue engineering and regenerative medicine given the biochemical signaling of salmon gelatin and electromechanical properties of polyvinylidene fluoride.