Electrospinning of Polymer-free Nanofibers from Cyclodextrin Inclusion Complexes

The electrospinning of polymer-free nanofibers from highly concentrated (160%, w/v) aqueous solutions of hydroxypropyl-beta-cyclodextrin (HP beta CD) and its inclusion complexes with triclosan (HP beta CD/triclosan-IC) was achieved successfully. The dynamic light scattering (DLS) and rheology measurements indicated that the presence of considerable HP beta CD aggregates and the high solution viscosity were the key factors in obtaining electrospun HP beta CD and HP beta CD/triclosan-IC nanofibers without the use of any polymeric carrier. The HP beta CD and HP beta CD/triclosan-IC solutions containing 20% (w/w) urea yielded no fibers but only beads and splashes because of the depression of the self-aggregation of the HP beta CD. The inclusion complexation of triclosan with HP beta CD was studied by isothermal titration calorimetry (ITC) and turbidity measurements. The characteristics of the HP beta CD and HP beta CD/triclosan-IC nanofibers were investigated by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). It was found that the electrospinning of HP beta CD/triclosan-IC solution having a 1:1 molar ratio was optimal for obtaining nanofibers without any uncomplexed guest molecules.