On the combination of techniques to improving the nanofiber electrospun mats properties for cell infiltration

S. BONGIOVANNI ABEL; G. A. ABRAHAM

Conferencia; 3rd Spanish Conference on Biomedical Applications of Nanomaterials (SBAN); 2020

In the last decades, electrospinning technology has been explored in the field of materials science with a special focus on biomedical applications such as tissue engineering and regenerative medicine. Despite the advantages of the electrospinning for the obtention of the mats, there are some drawbacks that seriously limit their performance in the regeneration of certain thick tissues: planar (2D) structure of densely and tightly compacted fibers, limited thickness, small pore size, and poor mechanical properties. However, by integrating electrospinning with other fabrication technologies (e.g. salt leaching, gas foaming, electrospraying, etc.) multifunctional 3D fibrous assemblies with micro/nanotopographical features can be created. Herein, we propose the use of the gas foaming technique after the electrospinning procedure to obtain 3D electrospun mats with useful properties for the cell infiltration applications. The versatility of the methodology allows its use for hydrophobic -PCL-, hydrophilic PVA-, and nanocomposites -PCL-nanoHAp- electrospun mats. In all the cases, the fiber diameters were lower than 2 µm, presenting the hydrophilic mats the lower diameters. Fibers have shown homogeneity, monodispersity, and defect-free. We emphasize in the use of benign solvents (acetic acid, water, and formic acid) in order to avoid the negative effects of toxic organic solvents during polymer processing and in the final material. The expansion of the matrices to achieve a 3D architecture was carried out using chemical agents for in situ gas generation (e.g. NaBH4), evaluating different immersion times and salt concentrations. The results confirm that the diameter of the fibers changes and also variations in the thickness of the membranes were achieved (> 1500% with respect to the initial one in the best of the cases for hydrophobic mats). Measurements of liquid extrusion porosimetry reveal the change in the average pore size after the gas foaming procedure on the electrospun mats. The study is currently in the phase of in vitro fibroblast growth evaluation in order to corroborate the improvement in cellular infiltration within the pores after the expansion procedures.