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

•PCL was superficially modified with oxygen plasma and antibacterial active structures.•Surface changes were followed by chemiluminescence, contact angle, ATR-FTIR, SEM, AFM.•Modified PCL showed excellent antibacterial activity against B. cereus and P. aeruginosa.•In vitro studies using L929 cells demonstrated good biocompatibility of the materials.•Monitoring of live cells provides a preliminary view before performing in vivo studies.