Electrospun biodegradable nanofiber nonwovens for controlled release of proteins

Electrospinning of emulsions composed of an organic poly(l-lactide) solution and an aqueous protein solution yielded protein containing nanofiber nonwovens (NNs) having a mean fiber diameter of approximately 350 nm. Cytochrome C was chosen as a hydrophilic model protein for encapsulation. SEM imaging and gas adsorption measurements were carried out to determine morphology and surface characteristics of the different nanofiber nonwovens. Transmission electron microscopy was used to clarify the localization of the protein within the NN. PLLA NNs exhibited a highly hydrophobic surface which led to a slow wetting. It was shown that the protein release was dependent on the surface tension of the release medium. Electrospinning of emulsions consisting of an organic solution of PLLA and an aqueous solution of hydrophilic polymers yielded fibers composed of a polymer blend. The resulting NNs exhibited a less hydrophobic surface, which gave us the opportunity to tailor the release profile via this technology. Furthermore it was investigated how the addition of different amounts of hydrophilic polymer to the aqueous phase influenced the morphology of the resulting NNs.