Improvement of biological response of YAG laser irradiated polyethylene

Abstract

PE was manufactured by thermocompression of PE micro beads. This end product was then irradiated by a 1064 nm YAG laser. In the first part the physical characteristics of untreated and laser irradiated samples are compared. DSC revealed a maximum of crystallinity of PE, and YAG laser treatment did not influence the crystallinity. Weattability between PE and the laser irradiated PE (Li-PE) was similar with about 37 mJ cm⁻². Differences appeared, however, as to the surface profile and the surface composition: increase of the roughness of 0.20 µm for PE vs. 0.29 µm for Li-PE; XPS reveals that traces of stripping agents on PE mostly disappeared after surface cleaning by YAG laser treatment. Biological tests confirmed the non-toxicity of polyethylene powder and revealed a 4-fold proliferation increase and a 2-fold vitality stimulation of L132 cells cultured on Li-PE with respect to those grown on untreated PE. No differences were observed as to the morphology and cell adhesion between the two samples. The modified surface morphology and surface composition may explain the improved biological reactions.