Fabrication of Bovine Serum Albumin-Loaded Coaxial Electrospun Thread with an Aligned Core-Shell Fibrous Structure

Threads or yarns are key building blocks in constructing complicated fibrous structures for many biomedical applications such as scaffolds to direct cells in tissue engineering applications. In this study, protein-loaded aligned fibers with core-shell structures were successfully fabricated by combining coaxial electrospinning with a rotating disk collector. A model protein, bovine serum albumin (BSA) as a core was incorporated into shell material, including PCL/gelatin (50:50) hybrid and then electrospun aligned core-shell fibers on the rotating disk. After manually twisting the aligned fiber bundle, the prepared threads were crosslinked with genipin. The fibers and thread morphologies were characterized by scanning electron microscopy (SEM), fluorescent microscopy (FM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR), and the threads tensile properties were then evaluated. The well-aligned fibers (with a mean diameter of 1.472±0.444 μm) with uniform core-shell structures without any bead formation and homogeneous protein incorporation into them were obtained using a rotating wheel at 1300 rpm. BSA-loaded threads with a diameter of 150-250 μm were finally prepared from aligned fiber bundle by keeping their well-aligned structure. The tensile tests revealed that fibrous thread with the modulus of 34.2 cN/tex had proper tensile properties for tissue engineering approaches. FTIR thus proved that the crosslinking was successful between thread and genipin. After crosslinking, threads retained their fibrous structure and demonstrated the improvement in the tensile properties (modulus increased to 40.64 cN/tex). These findings are promising to promote biomedical agents-loaded fibrous threads for tissue suturing and tissue regeneration applications.