A comparative study on pre- and post-production plasma treatments of PCL films and nanofibers for improved cell-material interactions

摘要

In this work, an atmospheric pressure plasma jet (APPJ) has been used to modify a 5% polycaprolactone (PCL) solution, after which the PCL solution was spin coated or electrospun to generate PCL films and nanofibers respectively. The APPJ treatment was found to have no effects on the chemical and physical properties of the PCL films, however, a strong influence on the morphology of electrospun PCL nanofibers could be observed. PCL nanofibers generated from the pristine PCL solutions contained multiple beads, while the PCL nanofibrous material generated from the APPJ-treated solutions consisted of nicely elongated, beadless PCL nanofibers. This enhanced electrospinnability was attributed to the strongly increased solution conductivity induced by the APPJ exposure. The APPJ treatment was also found to have minor effects on the chemical composition and the wettability of the nanofibers, which could be linked to the different surface morphology. All investigated pristine and APPJ-treated films and nanofibers unfortunately possessed poor cell-material interactions as a result of their high hydrophobicity. To cope with this issue, after spin coating and electrospinning, a second surface modification treatment making use of a dielectric barrier discharge (DBD) sustained in argon was also conducted. These treatments were found to considerably increase the wettability of PCL films and nanofibers without affecting their surface morphology. The enhanced wettability was caused by the incorporation of C=O functional surface groups by the performed DBD treatments. The treatments were also found to positively affect cell growth on PCL films and nanofibers, with the best cellular performance obtained for the APPJ/DBD-treated PCL nanofibers. A combination of plasma treatments can thus play a significant role in the preparation of ideal electrospun PCL scaffolds for tissue engineering applications.