Abstract
Currently, electroactive biomaterials have often been fabricated as tissue engineering scaffolds to provide electrical stimulation for neural tissue engineering. The goal of this work was to study the synergistic effect of electrical stimulation and nerve growth factor (NGF) on neuron growth. The composite meshes of polyaniline (PANi) and well-blended poly(L-lactic acid-co-epsilon-caprolactone)/silk fibroin (PS) incorporated with nerve growth factor (NGF) were prepared by coaxial electrospinning. The results showed that the increased concentration of PANi had a large effect on the fiber diameter, which was significantly reduced from 683 +/- 138 nm to 411 +/- 98 nm and then increased to 498 +/- 100 nm. The contact angles and Young's modulus decreased to 28.3 degrees +/- 5.4 degrees and 7.2 +/- 1.2 MPa, respectively, and the conductance increased to 30.5 +/- 3.1 mS cm(-1). The results of the viability and morphology of mouse Schwann cells on the nanofibrous meshes showed that PS-PANi-1 loaded with NGF exhibited the highest cell number after 5 days culture and the aligned nanofibers could guide cell orientation. The synergistic effects of electrical stimulation and NGF were also investigated via the growth and differentiation of rat pheochromocytoma 12 (PC12) cells. The scaffolds loaded with NGF under electrical stimulation could effectively support PC12 neurite outgrowth and increase the percentage of neurite-bearing cells as well as the median neurite length. More importantly, the NGF release from the conductive core-shell structure nanofiber could be increased by electrical stimulation. These promising results demonstrated that there was a potential use of this functional scaffold for nerve tissue regeneration.