Fabrication and morphology control of electrospun poly(γ-glutamic acid) nanofibers for biomedical applications

Poly(γ-glutamic acid) (γ-PGA) is a promising natural occurring polymer with excellent biocompatibility and biodegradability. In this study, we attempted to fabricate uniform electrospun γ-PGA nanofibers with morphology control for biomedical applications. By electrospinning γ-PGA solutions with a concentration of 16% containing trifluoroacetic acid (TFA) with different concentrations, we were able to fabricate smooth and uniform γ-PGA nanofibers with a diameter ranging from 255-603 nm. The influence of TFA concentration on the γ-PGA solution properties including viscosity, surface tension, and conductivity was systematically investigated in order to find the factors affecting the morphology of γ-PGA nanofibers. We show that with the increase of TFA concentration, the fiber diameter increases first and then decreases when the TFA concentration is increased to 12.5%. The fabricated smooth and uniform γ-PGA nanofibers were rendered with good water stability by a cystamine crosslinking reaction. Furthermore, the biocompatibility of the crosslinked PGA nanofibers was assessed by MTT assay of mouse fibroblasts cultured onto the fibrous mat. The fabricated smooth and uniform water-stable electrospun γ-PGA nanofibers with good biocompatibility may find many applications in tissue engineering and drug delivery.