Dual gradients of bioactive components on electrospun fibers for cell migration and controlled stem cell differentiation

The construction of gradient scaffolds to mimic the in vivo microenvironment for promoting tissue regeneration is attractive, especially by incorporating biochemical cues with physical guidance to manipulate cell behavior. Here, we report a general method to generate dual concentration-gradient of two types of bioactive components on scaffolds composed of uniaxially aligned electrospun nanofibers through layer-by-layer self-assembly. Different layers of collagen (COL) and chondroitin sulfate (CS) are sequentially coated onto the specific positions of uniaxially aligned electrospun polycaprolactone (PCL) nanofibers upon electrostatic attraction. In this case, dual stepwise gradients of COL and CS are generated along the fiber alignment. In demonstrating the potential application, the dual gradients can effectively promote the migration and proliferation of bone marrow stem cells (BMSCs) and spatially control their osteogenic differentiation. This simple strategy for generating dual gradients can be easily extended to different types of gradient scaffolds for bone regeneration and related applications involving cell migration, stem cell differentiation, and tissue interface.