Bacteria-responsive core-shell nanofibers and a process for the preparation thereof are described. The nanofibers release of an antibacterial agent in response to the presence of bacteria. The core of the nanofiber comprises a biocompatible polymer together with an antibacterial agent such as a quaternary ammonium compound, for example benzyl dimethyl tetradecyl ammonium chloride (BTAC). Surrounding the core is shell comprised of a bacterially degradable polymer, which is susceptible to break-down by bacterial enzymes such as lipase, or to acidic pH conditions. The shell may comprise, for example, polycaprolactone (PCL) and poly(ethylene succinate) (PES). The nanofibers may be incorporated into wound dressings.