title: Effects of different sterilization methods on the physico-chemical and bioresponsive properties of plasma-treated polycaprolactone films.
abstract: For most tissue engineering applications, surface modification and sterilization of polymers are critical aspects determining the implant success. The first part of this study is thus dedicated to modifying polycaprolactone (PCL) surfaces via plasma treatment using a medium pressure dielectric barrier discharge, while the second part focuses on the sterilization of plasma-modified PCL. Chemical and physical surface changes are examined making use of water contact angle goniometry (WCA), x-ray photoelectron spectroscopy and atomic force microscopy. Bioresponsive properties are evaluated by performing cell culture tests. The results show that air and argon plasmas decrease the WCA significantly due to the incorporation of oxygen-containing functionalities onto the PCL surface, without modifying its morphology. Extended treatment times lead to PCL degradation, especially in the case of air plasma. In addition to surface modification, the plasma potential to sterilize PCL is studied with appropriate treatment times, but sterility has not been achieved so far. Therefore, plasma-modified films are subjected to UV, H2O2plasma (HP) and ethylene oxide (EtO) sterilizations. UV exposure of 3 h does not alter the PCL physico-chemical properties. A decreased wettability is observed after EtO sterilization, attributable to the modification of PCL chain ends reacting with EtO molecules. HP sterilization increases the WCA of the plasma-treated samples, presumably due to the scission of the hydrophilic bonds generated during the prior plasma treatments. Moreover, HP modifies the PCL surface morphology. For all the sterilizations, an improved cell adhesion and proliferation is observed on plasma-treated films compared to untreated ones. EtO shows the lowest proliferation rate compared to HP and UV. Overall, of the three sterilizations, UV is the most effective, since the physical alterations provoked by HP might interfere with the structural integrity when it comes to 3D scaffolds, and the chemical modifications caused by EtO, in addition to its toxicity, interfere with PCL bioactivity.
authors.affiliation: Faculty of Architecture and Engineering, Department of Applied Physics, Research Unit Plasma Technology (RUPT), Ghent University, Ghent, Belgium. Rouba Ghobeira and Charlot Philips are first authors; Ria Cornelissen and Rino Morent are last authors.
authors.forename: Rouba
authors.initials: R
authors.lastname: Ghobeira
authors.forename: Charlot
authors.initials: C
authors.lastname: Philips
authors.forename: Heidi
authors.initials: H
authors.lastname: Declercq
authors.forename: Pieter
authors.initials: P
authors.lastname: Cools
authors.forename: Nathalie
authors.initials: N
authors.lastname: De Geyter
authors.forename: Ria
authors.initials: R
authors.lastname: Cornelissen
authors.forename: Rino
authors.initials: R
authors.lastname: Morent
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D053687:Adult Stem Cells / Q000166:cytology; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002448:Cell Adhesion; D049109:Cell Proliferation; D002478:Cells, Cultured; D005027:Ethylene Oxide; D006861:Hydrogen Peroxide; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D058626:Plasma Gases; D011091:Polyesters / Q000737:chemistry*; D051381:Rats; D013242:Sterilization / Q000379:methods*; D013499:Surface Properties; D023822:Tissue Engineering; D014466:Ultraviolet Rays; D017155:Wettability
chemical_list: D001672:Biocompatible Materials; D058626:Plasma Gases; D011091:Polyesters; C016240:polycaprolactone; D006861:Hydrogen Peroxide; D005027:Ethylene Oxide