Figure 1.

(a) Co-axial electrospinning set up with the core and the shell polymer solutions generating a spinning jet under a high voltage, from which the solvent is evaporated and dry fibers are collected on the oppositely charged plate. (b) Schematic representation of the developed fiber types, where the polyethylene oxide (PEO) shell is shown in light grey and the composition of the core is differentiated by the following colors: orange for zein (Z) only, green for zein with PEO, and violet for zein with stearic acid (SA). The drug tetracycline hydrochloride (T) is highlighted by yellow spheres. (c) Proposed drug release processes from T-loaded fibers. The process involves dissolution of the PEO shell in all fiber types and the burst release of dissolved T. Formation of pores during drug release was mostly observed in plasticizers-containing fibers. Larger pores were formed in (Z+SA+T)PEO. Nomenclature of the samples: composition of the core is shown in brackets, while the shell polymer is specified outside of the brackets.