Enhanced Control of Porosity in Electrospun Nanofiber Meshes

Electrospinning has gained popularity as a simple and versatile technique to produce synthetic polymeric ultrafine fibers. This technique allows the production of non-woven meshes with fiber diameters in the nanometer range, which results in a high surface area-to-volume ratio and high porosity. Additionaly, these nanofiber meshes can mimic the extracellular matrix of human tissues and, therefore, can be used as scaffolds for Tissue Engineering (TE) applications. However, electrospun nanofibers meshes have an important drawback to this type of application. The obtained pore size is tipically too small to allow cell penetration into the inner regions of the nanofibrous scaffold. To overcome this problem, PCL and PEO solutions were electrospun simultaneously to obtain a dual composition nanofiber mesh. Then,a selective dissolution of PEO nanofibers was performed.
These structures were characterized in terms of morphology, mechanical properties and cellular response. PCL nanofiber meshes with comparable volume of material were used as control. The dual composition electrospun nanofiber meshes showed an increased porosity when compared with PCL meshes. The biologic assays were conducted with human osteoblast-like cells (Saos-2 cell line). By SEM and confocal microscopy, it was shown that the cells can penetrate into the nanofibrous structure, forming a fully cellularized construct appropriated for TE applications.