Nanofibrous bicomponent scaffolds for the dual delivery of NGF and GDNF: controlled release of growth factors and their biological effects.

Electrospun fibrous scaffolds capable of providing dual growth factor delivery in a controlled manner have distinctive advantages for tissue engineering. In this study, we have investigated the formation, structure, and characteristics/properties of fibrous bicomponent scaffolds for the dual delivery of glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) for peripheral nerve tissue regeneration. GDNF and NGF were incorporated into core-shell structured poly(lactic-co-glycolic acid) (PLGA) and poly (D,L-lactic acid) (PDLLA) nanofibers, respectively, through emulsion electrospinning. Using dual-source dual-power electrospinning, bicomponent scaffolds composed of GDNF/PLGA fibers and NGF/PDLLA fibers with different fiber component ratios were produced. The structure, properties, and in vitro release behavior of mono- and bicomponent scaffolds were systematically investigated. Concurrent and sustained release of GDNF and NGF from bicomponent scaffolds was achieved and their release profiles could be tuned. In vitro biological investigations were conducted. Rat pheochromocytoma cells were found to attach, spread, and proliferate on all scaffolds. The release of growth factors from scaffolds could induce much improved neurite outgrowth and neural differentiation. GDNF and NGF released from GDNF/PLGA scaffolds and NGF/PDLLA scaffolds, respectively, could induce dose-dependent neural differentiation separately. GDNF and NGF released from bicomponent scaffolds exerted a synergistic effect on promoting neural differentiation.