Tailored nanofiber morphologies using modulated electrospinning for biomedical applications

The process of electrostatic fiber formation, or electrospinning, was used to generate polymer filaments with diameters in the 50-200 nm range. We have shown that in addition to process parameters such as solution concentration, spinning voltage, and deposition distance, an oscillating electric field can also influence the morphology of the electrospun nanofibers. Specifically, effects of the oscillating field strength and frequency, spinning voltage, and deposition distance on fiber diameter as well as size and number density of the beaded structures in the fibrous thin films are examined. The results of our study demonstrate that modulated field potential produces more uniform fibers. Increasing either the oscillating field strength or frequency yields more uniform average fiber diameter. Also, for systems with the "beads on a string" fiber morphology, increasing the oscillating field strength produces more uniform bead sizes. The ability to tailor fiber morphology using an oscillating electric field has promising implications in a wide range of applications including controlled-release drug delivery systems and biocompatible implants. We show here the potential of using electrospun nanofibers as a porous template for growing fuzzy conductive polymers to modify the surface of a neural recording microelectrode device. These hairy nanostructures can increase signal transport and mediate the mechanical property differences between the device and the soft brain tissues.