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, HO plasma (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.

The effect of electrospun polycaprolactone scaffold morphology on human kidney epithelial cells

“…Our results regarding the use of plasma treatment to increase the hydrophilicity of polymer scaffolds largely correlates with previous studies (Martins et al 2009;Yan et al 2013;Suntornnond et al 2016;Ghobeira et al 2017), showing an altered surface chemistry whilst retaining the same mechanical properties. This results in a dramatic increase in the hydrophilicity, as demonstrated through water contact angle tests.…”

Probing polydopamine adhesion to protein and polymer films: microscopic and spectroscopic evaluation

“…The PD layer could be expected to be approximately 50 nm thick which is the approximate thickness attained after immersion for 18 h seemingly regardless of substrate according to Liu et al [12] and Lynge et al [56]. The water contact angle (Table 1) for PD-coated SW was low (16.8 ± 4.0°), indicating high hydrophilicity and showed good similarity with Perikamana et al's [21] values for PD-coated PLLA-hemp composites (16.9 ± 1.6°).…”

Plasma Functionalization of Polycaprolactone Nanofibers Changes Protein Interactions with Cells, Resulting in Increased Cell Viability

“…To examine the plasma treatment effect on the interactions between PCL NFs and cells, cell adhesion and proliferation studies were conducted. Prior to cell seeding, untreated and plasmamodified PCL NFs were sterilized by exposure to UV light for 30 min[55][56] . Afterwards, human foreskin fibroblast (HFF) cells were seeded onto different PCL samples in a 24-well plate at a density of 40,000 cells/100 µl of medium per sample.…”