Electrospun Core-Sheath Nanofibers with Variable Shell Thickness for Modifying Curcumin Release to Achieve a Better Antibacterial Performance

The inefficient use of water-insoluble drugs is a major challenge in drug delivery systems. Core-sheath fibers with various shell thicknesses based on cellulose acetate (CA) were prepared by the modified triaxial electrospinning for the controlled and sustained release of the water-insoluble Chinese herbal active ingredient curcumin. The superficial morphology and internal structure of core-sheath fibers were optimized by increasing the flow rate of the middle working fluid. Although the prepared fibers were hydrophobic initially, the core-sheath structure endowed fibers with better water retention property than monolithic fibers. Core-sheath fibers had flatter sustained-release profiles than monolithic fibers, especially for thick shell layers, which had almost zero-order release for almost 60 h. The shell thickness and sustained release of drugs brought about a good antibacterial effect to materials. The control of flow rate during fiber preparation is directly related to the shell thickness of core-sheath fibers, and the shell thickness directly affects the controlled release of drugs. The fiber preparation strategy for the precise control of core-sheath structure in this work has remarkable potential for modifying water-insoluble drug release and improving its antibacterial performance.