Electrospun tri-layered zein/PVP-GO/zein nanofiber mats for providing biphasic drug release profiles.

Simple sequential electrospinning was utilized to create a functional tri-layered nanofiber mesh that achieves time-regulated biphasic drug release behavior. A tri-layered nanofiber mesh -composed of zein and poly(vinylpyrrolidone) (PVP) as the top/bottom and middle layers, respectively - was constructed through sequential electrospinning with ketoprofen (KET) as the model drug. PVP was blended with graphene oxide (GO) to improve the drug release functionality of PVP nanofiber as well as its mechanical properties. Scanning electron microscopy confirmed that the resultant nanofibers had a linear morphology, smooth surface, and tri-layered structure. In addition, X-ray diffraction patterns, differential scanning calorimetric analyses, and Fourier transform infrared spectra verified that the drugs were uniformly dispersed throughout the nanofiber due to good compatibility between the polymer and KET induced by hydrogen interaction. In vitro release test of the tri-layered structure, each component of which had distinct release features, successfully demonstrated time-regulated biphasic drug release. Also, it was confirmed that the drug release rate and duration can be controlled by designing a morphological feature - namely, mesh thickness - which was achieved by simply regulating the spinning time of the first and third layer. This multilayered electrospun nanofiber mesh fabricated by sequential electrospinning could provide a useful method of controlling drug release behavior over time, which will open new routes for practical applications and stimulate further research in the development of effective drug release carriers.