The research project envisages an experimental study that sheds light on the plasma properties of a cold plasma jet and the interactions of the plasma jet afterglow with the surface of a porous, biodegradable polyester matrix. OH radical concentrations in the plasma are measured with Laser Induced Fluorescence (LIF). Optical emission spectroscopy (OES) is applied to determine electron temperature and density. The penetration of the plasma effect in the polymer matrix is determined as a function of gas pressure and geometry of the sample.