Atmospheric pressure plasma jet: A facile method to modify the intimal surface of polymeric tubular conduits

Abstract

Atmospheric pressure plasma jet (APPJ) based modification as a facile method to modify the intimal surface of small caliber nanofibrous tubular tissue scaffolds for potential use as vascular-graft or spinal-cord conduit is reported here. Polycaprolactone, a biomaterial used in the US Food and Drug Administration approved scaffolds for various tissue regeneration and bioabsorbable suture applications, was electrospun into thin nano/microfibers to form seamless three-dimensional (3D) conduits of 4 mm intimal diameter. The 3D conduits were subjected to treatment with an APPJ produced by dielectric barrier discharge using controlled gas flow into ambient atmosphere. He/air or He/air/NH3 gas mixtures combined with 8.5 kV pulsed direct current signal proved effective in creating a sustained and reactive cold plasma jet to modify the intimal surface of tubular scaffolds without affecting its biomechanical properties. The treatment resulted in surface chemistry modification as indicated by enrichment of oxygenated functional groups. Surface chemistry was determined via x-ray photoelectron spectroscopy. Scanning electron microscopy and glycerol contact angle measurements were used to determine the surface morphology and surface wettability. The data support the conclusion that APPJ is as an effective, facile, and robust approach to modify the intimal surface of small-caliber (<4 mm) tubular conduits (successfully accomplished and initially reported here) for potential applications in vascular and neural tissue engineering.

Effect of Cold Plasma Treatment on Electrospun Nanofibers Properties: A Review

“…In another study, Tucker et al observed the aging impact for APPJ treated PCL nanofibers. 112 After plasma treatment, the amounts of N, C, and O onto the nanofibers surface were increased, confirmed by XPS analysis. However, after one storage week, the nitrogen corresponding peak disappeared due to the recombination of the functions created by plasma onto the surface (recombination of radicals and peroxides, reorientation of functional species, etc.).…”

“…Some studies demonstrated that atmospheric plasma treatment does not significantly affect this parameter, particularly in the case of He, Ar, or O 2 plasma treatments of PCL or gelatin nanofibers. 87,112,142 However, the study of Das et al, dealing with Ar and O 2 atmospheric plasma treatment of PVA/CS nanofibrous mats, revealed a significant increase in Young's modulus. 124 This phenomenon was explained in the literature by the formation of a highly cross-linked matrix thanks to the enhancement of hydrogen bonds formation, between active plasma species and the molecules, after the plasma treatment.…”

“…However, only one study demonstrated a nonsignificant increase of this mechanical parameter for an He atmospheric plasma treatment of PCL nanofibers, in opposition with the literature dealing with other polymers. 112 Both tensile properties (strength and stress) of nanofibers seem to be similarly affected after plasma etching. Indeed, in each case, plasma etching leads to a decrease of tensile stress 87,100,118,171 and strength.…”

“…Plasma treatment provides numerous interesting properties to the nanofibrous mats; however, it is also reported that the plasma treated materials suffer from a lack of stability after a certain time: indeed, aging effects were observed, as described previously. 99,112,142 It was described by Liguori et al with their study about the outcome of CAP treated gelatin nanofibers after 15 conservation days followed by immersion in phosphate buffer (pH 7.4) solution. 142 For untreated samples, the nanofibrous structure was kept after immersion.…”

“…In other studies, plasma treated nanofibers were also used, to a lesser extent, in nerve regeneration, − corneal, skin, , and vascular applications. In the case of nerve regeneration, Techaikool et al studied the effects of some plasma parameters on the biocompatibility of PLCL and poly­[( l -lactic acid)- co -glycolide] (PLGA) electrospun nanofibers for olfactory reconstruction application. , Their results showed a higher proportion of cultured olfactory ensheathing cells (OECs) on plasma treated PLCL and PLGA nanofibers of 26 and 32%, respectively, compared to untreated ones.…”