Surface modification of poly(epsilon-caprolactone) by oxygen plasma for antibacterial applications. Biocompatibility and monitoring of live cells

Abstract

Modifying biomedical implants by using materials with antibacterial properties would be advantageous when tackling bacterial colonization. However many of these modifications can lead to a rejection of the materials when implanted on patients. Poly(ε-caprolactone) (PCL) was superficially modified with antibacterial active structures (tetrabutylammonium, ampicillin, silver cations and cetylpyridinium) via a two-step process. Firstly, PCL was exposed to oxygen plasma for surface activation, and then immersed into aqueous solutions of biocides for their adsorption. The modified PCL materials were characterized by different techniques (ATR-FTIR, Chemiluminescence, contact angle, SEM, AFM) and their antibacterial properties were evaluated against the isolated bacteria that were found adhered to the PCL surface. The biocompatibility was studied by performing in vitro assays and live cell monitoring using murine L929 fibroblasts. The treatment modified the original PCL by giving it antibacterial properties. These new materials showed good biocompatibility except for the materials loaded with silver cations and cetylpyridinium. Also, live cell monitoring allowed visualizing cell-cell and cell-surface interactions in order to assess future tissue development before performing in vivo studies.