Characterization of an air-spun poly(L-lactic acid) nanofiber mesh

It was previously showed that PLLA nanofiber mesh promoted good endothelial cell proliferation. A new technique was developed to produce nanofibers by air jet spinning inside the tubular shape of vascular prostheses and to characterize this nanofiber mesh. Polymer macromolecule stability was assessed by gel permeation chromatography. Thermal analyses were conducted with differential scanning calorimetry and dynamic mechanical analysis on PLLA nanofibers obtained with 4% and 7% solutions (w/v) in chloroform. Polyethylene terephthalate (PET) was also treated with atmospheric pressure dielectric barrier discharge under air or nitrogen atmosphere to optimize PLLA nanofiber adherence, assessed by peel tests. Air spinning induced a reduction of number-average molecular weight (M_n) for the 7% PLLA solution but not for the 4% solution. The nanofibers were more crystalline and less sensible to viscoelastic relaxation as a function of aging in the 4% solution than in the 7% solution. Discharge treatment of the PET promoted identical surface modification on PET film and PET textile surfaces. Moreover, the best PLLA nanofibers adhesion results were obtained under nitrogen atmosphere. This study demonstrates that it is possible to coat the internal side of tubular vascular prostheses with PLLA nanofibers, and provides a better understanding of the air spinning process as well as optimizing nanofibers adhesion.