Figure 3.

SEM images of zein fibers after 48 h of incubation in PBS, magnification of ×2000. Composition of the core and the shell solutions are indicated on the vertical and horizontal panes, respectively. (a,c) (Z)E and (Z+SA)E are excluded due to poor electrospinnability and formation of beads. (b) (Z+PEO)E has completely lost its fibrous structure and turned into a film. (d–i) All fibers coated with PEO demonstrate enhanced water stability. (g–i) Formation of differently sized pores was observed in the drug-loaded fibers. Key: E, absolute ethanol; PEO, polyethylene oxide; SA, stearic acid; T, tetracycline hydrochloride; Z, zein; N/A, not available. Nomenclature of the samples: composition of the core is shown in brackets, while the shell polymer or solvent is specified outside of the brackets.