Improved fiber control through ohmic/convective flow behavior.

Electrospinning is an extracellular matrix production method for tissue engineering and biomaterial applications. However, current electrospinning methods generally produce small pore sizes that are insufficient for cell migration and infiltration. This work presents a new and simple technique which can produce highly aligned and patterned matrices with high porosity and micron-sized fibers. This work first identifies that the polymer solution dielectric constant has a strong impact on the instability criteria. By changing the dielectric constant of the solution through varying the dimethyl sulfoxide (DMSO) to chloroform concentration, we can suppress instability, which leads to ohmic flow electrospinning. When decreasing DMSO concentration from 10 to 1%, a clear transition, from randomly deposited to highly aligned fibers, is observed using a scanning electron microscope. Further experimentation shows that, at DMSO concentrations of 1–3%, increasing the applied voltage beyond 11 kV can lead to convective flow electrospinning. This technique of fiber control allows us to produce patterned and aligned porous matrices. Due to a two-solvent system with highly different vapor pressures, fibers exhibit rough surfaces which are advantageous for cell adhesion and growth. This technique has the potential to produce an alternating fiber matrix structure with both highly aligned and randomly deposited layers to control the matrix porosity. [ABSTRACT FROM AUTHOR]