Amine-Functionalized Electrically Conductive Core–Sheath MEH-PPV:PCL Electrospun Nanofibers for Enhanced Cell–Biomaterial Interactions

In the present study, a conducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) along with a biodegradable polymer poly(ε-caprolactone) (PCL) was used to prepare an electrically conductive, biocompatible, bioactive, and biodegradable nanofibrous scaffold for possible use in neural tissue engineering applications. Core-sheath electrospun nanofibers of PCL as the core and MEH-PPV as the sheath, were surface-functionalized with (3-aminopropyl) triethoxysilane (APTES) and 1,6-hexanediamine to obtain amine-functionalized surface to facilitate cell-biomaterial interactions with the aim of replacing the costly biomolecules such as collagen, fibronectin, laminin, and arginyl-glycyl-aspartic acid (RGD) peptide for surface modification. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the formation of core-sheath morphology of the electrospun nanofibers, whereas Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed successful incorporation of amine functionality after surface functionalization. Adhesion, spreading, and proliferation of 3T3 fibroblasts were enhanced on the surface-functionalized electrospun meshes, whereas the neuronal model rat pheochromocytoma 12 (PC12) cells also adhered and differentiated into sympathetic neurons on these meshes. Under a constant electric field of 500 mV for 2 h/day for 3 consecutive days, the PC12 cells displayed remarkable improvement in the neurite formation and outgrowth on the surface-functionalized meshes that was comparable to those on the collagen-coated meshes under no electrical signal. Electrical stimulation studies further demonstrated that electrically stimulated PC12 cells cultured on collagen I coated meshes yielded more and longer neurites than those of the unstimulated cells on the same scaffolds. The enhanced neurite growth and differentiation suggest the potential use of these scaffolds for neural tissue engineering applications.