Electrospinning cellulosic nanofibers for biomedical applications: structure and in vitro biocompatibility

Electrospinning of cellulose acetate (CA) was studied in relation to factors of solvent composition, polymer concentration, and flow rate to elucidate how the processing parameters impact electrospun CA structure. Fibrous cellulose-based mats were produced from electrospinning cellulose acetate (CA, Mn = 30,000, DS = 2.45) in acetone, acetone/isopropanol (2:1), and acetone/dimethylacetamide (DMAc) (2:1) solutions. The effect of CA concentration and flow rate was evaluated in acetone/DMAc (2:1) solution. The morphology of electrospun CA mats was impacted by solvent system, polymer concentration, and solution flow rate. Fibers produced from acetone and the mixture of acetone/isopropanol (2:1) exhibited a ribbon structure, while acetone/DMAc (2:1) system produced the common cylindrical fiber shape. It was determined that the electrospinning of 17 % CA solution in acetone/DMAc (2:1, w/w) produced fibers with an average fiber diameter in the submicron range and the lowest size distribution among the solvents tested. The solution flow rate had a power law relationship of 0.26 with the CA fiber size for 17 % CA in acetone/DMAc (2:1). Solvent composition and flow rate also impacted the stability of the network structure of the electrospun fibers. Only samples from acetone/DMAc (2:1) at solution flow rates equal or higher than 1 mL/h produced fibrous meshes that were able to preserve their original network structure after deacetylation. These samples after regeneration showed no residual DMAc and exhibited no cytotoxic effects on mammalian cells.