The electrospun scaffolds have two types of porosity including the porosity along the axis of fibers and the porosity between fibers.Īccordingly, the porosity between fibers plays a crucial role in the infiltration and the attachment of cells into a scaffold. However, they have been faced with some challenges leading to reduction of the versatility of electrospinning ( 1, 7). Beside coaxial electrospinning, various techniques such as immersion coating ( 3, 4), chemical conjugation ( 5, 6) have been used to embed the bioactive molecules in nanofibers structure. In core-shell electrospun scaffold, the shell provides the bioactivity originated from biopolymer containing macromolecules while, a synthetic polymer as the core induces the mechanical and the structural integrity ( 1, 2). It is classified as a modified electrospinning, in way that a single capillary replaces with an inner capillary surrounded by outer tube. Coaxial electrospinning is a versatile method for the fabrication of two or more polymers in a form of a core-shell scaffold with three dimensional (3D) architecture. These properties are consisted of high mechanical behaviors, surface functionality and the controlled release of bioactive macromolecules in an engineered scaffold ( 1). The induction superior properties into a scaffold are effective strategy to tackle many challenges in tissue regenerations. Further biological tests should be conducted to evaluate this platform as a three dimensional scaffold with the capabilities of releasing the bioactive molecules in a sustained manner. It was hypothesized that the core-shell PU/Cs nanofibers can be used as a potential platform for the bioactive scaffolds in tissue engineering. The thermal degradation of core-shell PU/Cs was similar to PU nanofibers degradation due to the higher PU concentration compared to other components. DSC analysis showed that the inclusion of Cs/PEO led to the glass temperature of the composition increased significantly compared to those of neat PU nanofibers. It that seems the inclusion of Cs/PEO to the shell, did not induce the significant variations in the crystallinity in the core-shell nanofibers. TEM image confirmed the PU/Cs core-shell nanofibers were formed apparently.

SEM images exhibited that the core-shell PU/Cs nanofibers were spun without any structural imperfections at the optimized processing conditions. Several methods including SEM, TEM, FTIR, XRD, DSC, TGA and image analysis were utilized to characterize these nanofibrous structures. In addition, the synergistic effect of ZnO and Co 3O 4 also plays an important role in improving the electrochemical performance.In this paper, polyurethane (PU), chitosan (Cs)/polyethylene oxide (PEO), and core-shell PU/Cs nanofibers were produced at the optimal processing conditions using electrospinning technique. This excellent electrochemical performance is attributed to its unique porous hollow structure and unique heterojunction electrode interface, which improves the Li + storage capacity, increases the contact area between the electrode and the electrolyte, and improves the overall electrochemical activity. When the current density is 0.6 A/g, the discharge capacity is 420 mAh g −1. As anode of lithium-ion batteries (LIBs), ZnO/Co 3O 4 has good cycling stability, the specific discharge capacity of ZnO/Co 3O 4 is stable at about 640 mAh g −1 after 200 cycles, and its coulombic efficiency (CE) is stable above 95% after the first 20 cycles. Herein, a low-temperature self-assembly calcination and hydrothermal strategy of imidazole-based Zn-Co-MOF was used. In this work, metal–organic frameworks (MOFs) were used as precursors to prepare Zn/Co oxide with a porous dodecahedral core-shell structure.

Core shell at