Triaxial Electrospun Nanofiber Membranes for Controlled Dual Release of Functional Molecules

Abstract

A novel dual drug delivery system is presented using triaxial structured nanofibers, which provides different release profiles for model drugs separately loaded in either the sheath or the core of the fiber. Homogenous, coaxial and triaxial fibers containing a combination of materials (PCL, polycaprolactone; PVP, polyvinylpyrrolidone) were fabricated. The drug release profiles were simulated using two color dyes (KAB, keyacid blue; KAU, keyacid uranine), whose release in physiological solution was measured using optical absorption as a function of time. To reach the level of 80% release of encapsulated dye from core, triaxial fibers with a PCL intermediate layer exhibited a ~24× slower release than that from coaxial fibers. At the same time, the hygroscopic sheath layer of the triaxial fibers provided an initial burst release (~ 80% within an hour) of a second dye as high as that from conventional single and coaxial fibers. The triaxial fiber membrane provides both a quick release from the outer sheath layer for short-term treatment and a sustained release from the fiber core for long-term treatment. The intermediate layer between inner core and outer sheath acts as a barrier to prevent leaching from the core, which can be especially important when the membranes are used in wet application. The formation of tri/multiaxially electrospun nanofibrous membranes will be greatly beneficial for biomedical applications by enabling different release profiles of two different drugs from a membrane.

Nanofibers Fabricated Using Triaxial Electrospinning as Zero Order Drug Delivery Systems

“…[20][21][22][23] There are very few investigations into side-by-side electrospinning to generate Janus nanofibers, [24][25][26][27][28][29] and even fewer reports on multiple-layer nanofibers. [30][31][32][33][34][35] The slow development of multiple-fluid electrospinning processes is related to their difficulty of implementation. The successful preparation of multi-component fibers requires the spinning fluids to have good compatibility, so that they can be drawn together by electrical forces without any coagulation.…”

Dynamic and Responsive Growth Factor Delivery from Electrospun and Hydrogel Tissue Engineering Materials

“…[39a] The coaxial method can also be used to layer different drugs to provide successive release of multiple agents. [40] Han and Steckl developed a model electrospun material with three distinct radial layers to deliver multiple drugs with distinct release profiles (Figure 4). [40] Using color dyes as model drugs, the dye in the hygroscopic outer sheath layer displayed a burst release, while the dye in the core showed sustained release for 50 h as it was slowed by an intermediate hydrophobic layer and the other sheath.…”

“…[40] Han and Steckl developed a model electrospun material with three distinct radial layers to deliver multiple drugs with distinct release profiles (Figure 4). [40] Using color dyes as model drugs, the dye in the hygroscopic outer sheath layer displayed a burst release, while the dye in the core showed sustained release for 50 h as it was slowed by an intermediate hydrophobic layer and the other sheath. [40] This method could be employed for any active agent stable in the electrospinning solution and can also provide a nonsolvent layer for active agents unstable in the volatile electrospinning solution.…”

“…[40] Three concentric needles are used to dispense separate spinning solutions to create fibers with three distinct radial layers. Dye added to the other layer displayed a burst release while the dye in the core displayed a sustained release after traveling through the intermediate sheath layer.…”

Nanosized sustained-release drug depots fabricated using modified tri-axial electrospinning

“…Similarly, traditional tri-axial electrospinning always uses an electrospinnable outer fluid [32][33][34][35][36][37][38][39][40]. A modified tri-axial process focused on the exploitation of un-spinnable liquids has also been reported [28].…”