Controlling the Orientation of Electrospun Nanofibers by Conductive-Insulating Hybrid Collectors

Fiber orientation is one of the important morphological characteristics of electrospun mats. Electric field between the nozzle and collector which is extremely influenced by electrical conductivity of the collector can be controlled to tailor the orientation of electrospun fibers. We have presented the conductive-insulating collectors as novel means to localize conductive area on the collector surface and subsequently reorganize the electric field. It is demonstrated that the electrospun nanofibers deposit with specific geometries on the hybrid collectors compared to the conventional conductive collectors. In addition، insulting area with different geometries results in different fiber orientations. The square geometry leads to wavy nanofibers with preferentially unidirectional alignment whereas straight nanofibers with completely random orientation are obtained by a collector of circular geometry. These observed morphological changes may be attributed to probable changes in the electrical field. It is also shown that the gap size between the insulating area and the conducting surface influences the fiber orientation in determining bigger gap، lower fiber density and more aligned orientation. Furthermore، the nanofibers deposited on the non-contacting insulating area show no wavy morphology. Our simple strategy can be used for precise tailoring of fiber orientation of the electrospun scaffolds in a desired tissue.